DT-5A theodolite Repair manual.pdf

Preface

This series of electronic theodolite can realize automatic

measurement calculation, storage, display and other functions by applying the microcomputer technology. It can display the measured values of horizontal angle and vertical angle simultaneously. By combining with range finder and data recorder, it can also constitute combined electronic tacheometer which can display and record angle and distance value, and it can automatically correct the instrument error and complete multiple-model measurement such as angle and distance.

This series of electronic theodolite can be used for control measurement, and also for engineering measurement for mine, railways, water conservancy, topographic survey, and many other engineering measurements. When maintaining the electronic theodolite, it is necessary to know the working principle, performance, basic structure, maintenance of the product first. At the same time, it is required to have certain experience in measurement instrument maintenance, basic knowledge of circuit, and experience in using the common electronic test equipment (e.g. oscilloscope, voltmeter, regulated voltage supply, etc.), and learn to examine, regulate, maintain the instrument. Generally, the following three aspects shall be known:

1. Carefully read the Instructions for product, and preliminarily examine the instrument. Learn about the performance, basic structure and routine correction method of the instrument and

some problems can be solved in case of no instrument removal. 2. Carefully examine the instrument, including complete

instrument examination and electric signal examination after removal, to confirm the fault reason.

3.Adjust and repair the instrument according to the examination results. Various indexes and functions shall be checked normal or not after adjusting and repairing.

Contents 1.1 Operation principle........................错误！未定义书签。

I. Angle measurement part ..........错误！未定义书签。 II. Functional software ................错误！未定义书签。

1.2 About instrument performance ....错误！未定义书签。 I. Basic function introduction .....错误！未定义书签。 II. Name of instrument components (see Figure 1-1 and 1-2) ........................................................................... 1 III. Introduction about electrical circuit signal of angle measurement ........................................................ 3 IV. Inspection of complete equipment ........................ 11

1.3 Basic operation ................................................................. 3 I. Operation panel and operation keys (see Figure 1-3)......................................................................................... 3 II. Display and display label.......................................... 5

SDHDVD................................................................................. 5 III. Function setup ......................................................... 6 Ⅳ. Charging and Storage of Rechargeable Batteries . 9

2.1 Over-tightness of the vertical axis during rotation ..... 14 I. Shedding of horizontal grating circle...................... 14 II. Blocking of the vertical axis ................................... 14

2.2 Over-tightness of the horizontal axis during rotation. 15 2.3 Maintenance of horizontal tangent screw ................. 15 2.4 Maintenance of vertical tangent screw......................... 19 2.5 Common faults of WILD tribrach............................. 22

I. Sliding of the level press board................................ 22 II. Shaking of the foot screw ............................................... 23

III. Tightness of the foot screw ....................................25 2.6 Common faults of the slide pedestal ..........................27

I. Malfunction of the locking mechanism of the pedestal..........................................................................27 II. Sliding of the level press board ..............................28 III. Tightness of the foot screw ....................................30

3.1 Cause and maintenance of fault of not being able to start-up ..................................................................................32

I. Insufficient battery power........................................32 II. Loose connection of power wire .............................33 III. Fault of electronic compensator ...........................36 IV. Fault of LCD ...........................................................37 V. Fault of the Mainboard.........................................38

3.2 Non Display of the Zero Position of the Vertical Angular..................................................................................40

I. The method of using adjustable electric resistance to adjust the zero-crossing voltage: .................................41 II. Method to adjust the zero-crossing voltage with software .........................................................................43 III. Method to adjust the zero-crossing voltage with software without any oscillograph ..............................47

3.3 Fault Maintenance of the Angle Measurement ............51 I. Fault of Horizontal Angle Measurement ................51 Ⅱ. Fault of vertical angle measurement.....................58

3.4 Fault maintenance of electronic compensator .............66 Ⅰ. Change of electronic compensator ........................66 Ⅱ. Zero correction of electronic compensator...........67

III. Precision Calibration for Electronic Compensator....................................................................................... 73 IV. Test on the Compensation Precision of Compensator ................................................................ 76

3.5 Setting of Index Error, Collimation Error, and Zero Error for Compensator........................................................ 76

SET F1 .................................................................... 78 SET F2 .................................................................... 78 SET ............................................................................... 78

4.1 Check whether the plate level axis is perpendicular to vertical axis as well as make correction ............................. 80

I. Examination .............................................................. 80 II 、Correction............................................................ 81

4.2 check whether the circular level axis is parallel to vertical axis as well as make correction ............................. 82

I、 Examination .......................................................... 82 II、 Correction............................................................ 82

4.3 Inspection and Correction for Whether Horizontal Wire of Cross Wire is Perpendicular to Vertical Axis....... 84

I. Examination .............................................................. 84 II. Correction................................................................ 85 III. Cautions ................................................................. 85

4.4 Examination and Correction for Whether Collimation Axis is Perpendicular to Horizontal Axis of Telescope...... 86

I. Examination .............................................................. 86 II. Correction................................................................ 87

4.5 Examination and Correction for Coincide Between

Collimation Axis of Optical Plummet and Central Line of Vertical Axis ..........................................................................88

I. Examination ..............................................................88 II. Correction ................................................................89

Appendix I: Error Information...................................................91

Chapter I About this instrument 1.1. Name of instrument components (see Figure 1-1 and 1-2)

(1)

(10)

(13)

(8)

(11)

(14)

(2)

(5)

(7)

(4)

(15)

(12)

(16)

(3)

(6)

(9)

(Figure 1-1)

1

1. carrying handle 2. handle screw 3. sighting collimator 4. vertical tangent screw and motion clamp 5. operating key 6. RS-232C communication interface 7. objective lens 8. plate level 9. display window 10. eyepiece 11. base plate 12. foot screw 13. focusing knob 14. battery 15. horizontal tangent screw and motion clamp 16. base locking lever

2

1.2 Basic operation I. Operation panel and operation keys (see Figure 1-3)

(Figure 1-2)

The functions of each key on the panel (Figure 1-2) are as follows:

Key Function 1 Function 2

OSET Zero setting for horizontal angle

Distance measurement

HOLD Lockup of horizontal angle Re-measurement of horizontal angle

Illumination of the display The second function selection

3

R / L Levo-incremental reading /dextro-incremental reading of horizontal angle

Setting mode

V / % Vertical angle/percent slope Output of measurement data

Power

4

II. Display and display label Start, then the display will display all the symbols firstly (see

Figure 1-3) and then display the symbol which requires the vertical angle to be set to zero.

SDHDVD 06–03–20 14：38%

VA 9 0 ° 0 0 ′0 0 ″m

HA L

R 0 ° 0 0 ′0 0 ″gon

CRN REP HOLD SFT

(Figure 1-3)

The meanings of the display symbols are as follows:

Display Meaning Display Meaning

SD Measurement of slope distance

HOLD Lockup of horizontal angle

HD Measurement of horizontal distance

TILT Oversize inclination compensation t

VD Measurement of height difference

Battery electric power display

VA Vertical angle % Percent vertical slope

5

HALLevo-incremental reading of horizontal angle

m Unit for distance measurement：m

HAR

Dextro-incremental reading of horizontal angle

gon Angle unit

SFT The second function selection

06-03-20 Date

REP Repetition of measurements for horizontal angle

14：38 Time

CRN Function of inclination compensation

Auto off function

III. Function setup

(I) Functions This series of instrument provides many optional functions and

its options are as follows: 1. Inclination compensator of vertical angle: ON, OFF 2. Option for vertical, horizontal and 0 angle: 90º (ON), 0º(OFF). 3. Auto power off: Option of auto power off after the instrument

has been operated for 20min (ON). No auto power off option(OFF). 4. The minimum angle display: 1″, 5″, 10″. 5. Baud rate setup: 1200, 2400, 4800, 9600. 6. Record media option: Serial Port (OFF), Instrument memory

6

(ON). 7. Option for collimation error correction: ON, OFF 8. Option for “Angle” and “Gon”: Angle< OFF>, Gon< ON>. (II) Functional allocation of the keys under the setup modes are

as follows: [OSET]：Circularly select the setup item [HOLD]：Circularly select Clock setup item (M/D/Y, H/M/S).

[L / R ]： Switch option value of setup item by circulating upward or plus 1 to the option of clock setup item. [V / % ]：Switch option value of setup item by circulating upward or minus 1 from the option value of clock setup item. [SFT]：Confirm the setup, exit setup mode and return to angle measurement mode.

(III) Operation method for function setup 1. Press [SFT] key first and then press [L / R ] key, the

instrument will enter into setup mode (see Figure 1-4). 2. Press [0SET] key to select the setup options 1-7. If you want

to select the minimum angle reading of the forth option, press [0SET] key for three times, shown as Figure 1-5.

07–06–07 9:16

1. OFF

07–06–07 9:16

4. 1″

(Figure 1-4) (Figure 1-5)

7

3. Press [L/R] key or [V / % ] key to change the setup of selected option. If you want to select 5″as the minimum angle reading, press [L/R] key once, shown as Figure 1-6.

07–06–07 9:16

4. 5″

07–06–07 9:16

VA 90°14′32″

HAR 168°25′01″


4. Press [SFT] key to save the setting and return to the angle measurement mode (see Figure 1-7).

(Ⅳ) Clock setting 1. Press [SFT] key, and press [L/R] key again, the instrument

will turn into set mode (see Figure 1-8). 2. Press [HOLD] key to select the option for clock setting (year,

month and day, hour, minute and second), and the selected clock option will blink (see Figure 1-9).

07–06–07 9:16

1. OFF

07–06–07 9:16

. . . . . .


3. Press [L/R] key or [V/%] key to increase or reduce clock

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option. If you want to change the 07–06–07 in the Figure into 07–08–07, press [HOLD] key for once to change option into the “Month” from “Year”, and the “Month” (06) will blink. Press [L/R] key for twice to change “06”into “08”, shown as Figure 1-10.

07–08–07 9:16

. . . . . .

07–08–07 9:16

VA 90°14′32″

HAR 168°25′01″


4. Press [SFT] key to save all time settings and return to the angle measurement mode (see Figure 1-11).

Ⅳ. Charging and Storage of Rechargeable Batteries

Note: make sure to switch off the power of the instrument before taking down the battery.

This instrument utilizes an exclusive charger and battery pack with a voltage of 7.2V. The battery case shall be connected with the exclusive charger before the charger is connected with power. The batteries begin to be charged when the charge lamp is red and the charging is completed when the indicating lamp is green. The battery case shall be taken off after the power is cut off.

This is a quick charger that can complete charging 80% of the 9

batteries’ capacity with only 4 hours. If it is needed to be fully charged, another 2 to 4 hours’ trickle charging is required. Should be noticed that the complete charging time take no more than 24 hours.

The batteries shall be fully charged before being stored and be charged again every other three months. If the batteries are discharged before storage or not charged in excess of the allotted time limit of three months, the battery capacity may decline when it is charged again. The Display Label shows the status of battery pack power.

： Battery with sufficient power

： Battery with limited power, which may be measured

： Battery with limited power, which may be measured

： battery insufficient power, which is needed to be

replaced

10

1.3 Inspection of complete equipment 1. To check the functions of the functional keys are normal or

not. 2. To check the measured angle is hopped

(1) Level the instrument and start it to carry out zero crossing, and observe one far point A, and then record the vertical and horizontal angle values. Rotate the vertical axis and horizontal axis several times and observe point A repeatedly and also read the vertical and horizontal angle values, and the variation shall not exceed 5″.

(2) Carry out fine adjustment for the vertical and horizontal handwheels， and observe whether the horizontal and vertical indicated angle values are in ordered change. In case of abnormal condition, it shows that the horizontal or vertical angle has hop problem.

3. To check whether the left and right rotation increments are correct

4. To check the zero crossing conditions in different directions Level the instrument and start it, and rotate the telescope at a place near to 90° of the direct position of telescope (left of plate), and angle value shall be displayed vertically. (In case that “SET 0” is always displayed, it shows that the problem of no zero crossing exists for this instrument.) (1) Stop the instrument and the telescope heads downwards, and start the instrument and carry out zero crossing upwards, and the vertical angle value shall be recorded by aiming at one target. (2) Stop the equipment and the telescope heads upwards, and

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start the equipment and carry out zero crossing downwards, and the vertical angle value shall be recorded by aiming at the same target as above. (3) The difference between two values shall be less than 10″. If the difference is excessively big, it shows that the problem of excessively high zero-passage level exists.

5. To check the index error: (1) Exactly level the instrument and start it to carry out zero crossing. (2) Rotate the telescope to make it in the level position of direct position of telescope. Aim at target A and record the reading value A1 of vertical angle.

(3) Rotate the alidade at 180º to make the telescope (reversed telescope) aim at target A again, and then record the reading value A2 of vertical angle. Half of │A1+A2–360│ will be the index error and this value shall not exceed 10″. If it exceeds 10″, it shows that the instrument has the problem of oversize index error.

6. To check the compensation precision of vertical angle (1) The instrument is arranged on the calibration stand (Wherein, one foot screw shall be aligned to the collimator), and then exactly level the instrument and start it to carry out zero crossing, and guarantee that the compensator is in the state of “on”. If the vertical angle value in the vertical angle value column of the second line is not displayed, but “TILT” is shown, it shows that the zero position of electronic compensator is oversize, and repair is needed for it firstly.

(2) The telescope aims at the origin 0 of reticule of collimator

12

(Some collimators are provided with near point reticules used to inspect the minimum distance of visibility and optical axis of the telescope. The origin 0 here refers to the origin 0 on the reticule at the objective lens focus of the collimator equal to the target in infinitive distance, similarly herein after), and record the vertical angle value A. (3) Rotate the foot screw to make the instrument be inclined by 3′ backwards. (If the reticule scale unit of the collimator is 18″, it is necessary to make the telescope aim at the vertical thread +10 of reticule of collimator namely, moving by 10 lattices.) Rotate the focusing sleeve to make the telescope aim at the origin 0 of reticule of collimator, and then record the vertical angle value A1. (4) Rotate the foot screw to make the telescope aim at the vertical thread -20 of reticule of the collimator (namely, the instrument is inclined by 3′ forwards), and rotate the focusing sleeve to make the telescope aim at the origin 0 of reticule of collimator , and then record the vertical angle value A2.

(5) The absolute values of A1–A and A2–A shall be less than 6″ respectively, if it is oversize, it means that the compensation precision is oversize.

13

Chapter II Maintenance of Common Mechanical Faults

2.1 Over-tightness of the vertical axis during rotationI. Shedding of horizontal grating circle

Strong vibration of the instrument may cause the horizontal grating circle to shed with glue failure; in this case, the rotation of the vertical axis may become over-tight. By dismantling the display on one side of the telescope, you can find that the horizontal grating circle (the grating circle on the top) will not follow the rotation of the alidade when the alidade is rotating. Check four directions of the whole circumference, at an interval of 90° with a 0.02mm feeler gauge. The feeler gauge shall be able to insert between any two grating circle . In case the feeler gauge can not be inserted between a specified pair of grating circles, we can determine that the horizontal grating circle has fallen off due to glue failure. When maintaining such kind of failure, it is necessary to calibrate the circle or return the grid circle to the factory for reparation.

II. Blocking of the vertical axis

If the alidade can not rotate or is hard to rotate, it is mainly because that the vertical axis is blocked. At this time, the alidade shall not be rotated forceably; otherwise, the vertical axis will be scrapped due to the seizure of it. As the vertical axis requires very high fitting accuracy, it is necessary to return it to the factory for maintenance, because that repairing it with non-professional tools can hardly ensure the fitting accuracy.

14

2.2 Over-tightness of the horizontal axis during rotation For this kind of horizontal axis structure, no over-tightness

during rotation will occur under normal operation. Over-tightness of this kind of horizontal axis is generally caused by long term usage, strong vibration, collision, or scraping between the two vertical grating disks. Check four directions of the whole circumference, at an interval of 90° with a 0.02mm feeler gauge. The feeler gauge shall be able to be inserted between any two grating circles; if the feeler gauge can not be inserted between a specified pair of grating circles, it can be determined that scrapping has occurred. For the maintenance methods, refer to section II—failures in vertical angle measurement in 3.3—Maintenance of the failures in vertical angle measurement.

2.3 Maintenance of horizontal tangent screw Figure 2-1 shows the assembly and disassembly of the tangent screw.

1. Screw out the four set screws 2 of the fixed display 1. 2. Take down the display 1 and pay attention to the

connections of the circuit. 3. Screw out the base of the terminal spring 5 and make sure

that the spring and the base of the terminal spring will not spring out.

4. Screw out two set screws 4 with an inner hexagon spanner. 5. Take down the horizontal brake and micro handwheel unit

3. 6. Screw out two hexagon socket set screws 7 and take down

15

the micro handwheel 6. 7. Screw out the set screw 8 and screw out the brake

handwheel 9 counterclockwise. 8. Screw out two countersunk set screws 10 and one adjusting

screw 11 and then take down the spacing ring 12. 9. Take down the horizontal stationary bushing 13 from the

horizontal locking lever 14. 10. Screw out two set screws 15 and take down the brake shift

fork 16. 11. Screw out the micro screw rod 17. 12. Brush all the parts carefully with gasoline. Make sure that

the adjustable pad of white nylon on the horizontal locking lever does not get lost during the brushing.

13. Refer to Figure 2-1 and assemble the horizontal brake and micro handwheel unit in a sequence that is reverse to dismantling sequence in 6-11. Apply a proper amount of handwheel oil at the positions between the micro screw rod 17 and the horizontal locking lever 14 and between the horizontal locking lever 14 and the horizontal stationary bushing 13. The screws are required to be tight and the rotation of the handwheels shall be smooth. No over-tightness and lost motion is allowed at any position. If over-tightness or lost motion occurs, it is necessary to eliminate it by adjusting the adjusting screw 11. After the above said adjustment, the adjusted position shall be applied with varnish for sealing.

16

3

1

2

7 8 4 1012

1314

1516

17

5

69

11

(Figure 2-1)

17

1. Display 2. Set screw 3. Brake and

micro hanwheel unit

4. Holding screw

5. Base of the terminal spring

6. Micro handwheel

7. Allen screw 8. Set screw

9. Brake handwheel

10. Countersunk set screw

11. Adjusting screw

12. Spacing ring

13. Horizontal stationary bushing

14. Horizontal locking lever

15. Set screw 16. Brake shift fork

17. Micro screw rod

14. Refer to Figure 2-1 and arrange the horizontal tangent screw on the support in the sequence reverse to the disassembling sequence specified in 1-5. During the assembling process, the holding screw 4 shown in Figure 2-1 shall be inserted into the V-shape slot of the horizontal stationary bushing with moderate pushing force. The assembly shall meet the standard that the horizontal brake and micro system can rotate freely without the risk of being pulled out. 15. Rotate the handwheel 9 shown in Figure 2-1 to make the brake handwheel operate reliably with a braking region of 45°–90°; then tight the holding screw 4.

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2.4 Maintenance of vertical tangent screw Figure 2-2 shows the disassembly and assembly of the vertical

giggle system of this series of electronic theodolite. 1. Take down the battery case 1 from the right baffle plate 2. 2. Back out the six set screws 3 of the fixed right baffle plate 2. 3. Take down the right baffle plate 2 and pay attention to the

positions of the inner connections. 4. Back out the base of the terminal spring 4 and make sure that

the spring and relevant accessories do not spring out. 5. Back out a holding screw 5 and take out the vertical micro

handwheel 6 with an inner hexagon spanner. 6. Back out two Allen screws 7 and take down the micro

handwheel 8. 7. Back out the set screw 9 and back out in an anti-clockwise

direction the brake handwheel 10. 8. Back out 2 sunk screws 11 and one adjusting screw 12 and

then take down the spacing ring 13. 9. Take down the stationary bushing 14 from the vertical brake

rod 15.

19

1

2

3

4

56910

1112

14

1615

1718

8 7 13

(Figure 2-2)

20

1. Battery case

2. Right baffle plate

3. Set screw 4. Base of he terminal spring

5. Holding screw

6. Vertical micro handwheel

7. Set screw 8. micro handwheel

9. Set screw 10. Brake handwheel

11. Sunk screw

12. Adjusting screw

13. Spacing ring

14. Stationary bushing

15. Vertical brake rod

16. Set screw

17. Shift fork 18. Micro screw rod

10. Screw out two set screws 16 and take down the shift fork 17. 11. Screw out the micro screw rod 18. 12. Brush carefully all the parts and elements and make sure that

the adjusting pad of white nylon on the vertical brake rod 15 does not get lost during the brushing.

13. Refer to Figure 2-2 and assemble the vertical brake and micro handwheel in the sequence reverse to the disassembling sequence specified in 6-11. Apply a proper amount of handwheel oil between the micro screw rod 18 and the vertical brake rod 15 and between the stationary bushing 14 and the vertical brake rod 15. After the assembling process, check whether the screws are tight and the rotation is smooth. No over-tightness or lost motion is allowed at any position. If the over-tightness or lost motion does occur, it is necessary to eliminate it through adjusting the adjusting screw 12. After the above adjustment, it is required to apply some varnish to

21

the adjusting screw for sealing. 14. Refer to Figure 2-2 and arrange the vertical tangent screw on

the support in the sequence reverse to that specified in 1-5. 15. During the assembling process, the holding screw 5 shown in

Figure 2-2 shall be inserted into the V-shape slot of the horizontal stationary bushing with moderate pushing force. The assembly shall meet the standard that the horizontal brake and micro system can rotate freely without the risk of being pulled out.

16. Rotate the handwheel 10 shown in Figure 2-2 to make the brake system operate reliably with a braking region of 45°–90°; then tight the holding screw 5.

2.5 Common faults of WILD tribrach I. Sliding of the level press board

1

2

3

4

5

6

7 8

(Figure 2-3) 1.lock screw 2. base backing nut 3. elastic washer

4. foot screw 5. level bearing 6. bearing backing nut

7.φ3 steel ball 8. level base plate

22

Sliding up and down of the level press board may cause that the plate level can not swing to level, which is resulted from loosening of the backing nut of the level bearing. The maintenance procedures are as follows:

1. Screw the lock screw 1 tight clockwise (see Figure 2-3) to unlock the wrench handle. Rotate the wrench handle anticlockwise and remove the alidade.

2. Use a plate to remove the base backing nut 2. 3. Remove 2 pieces of elastic washer 3 (some instrument has

only one piece). 4. Turn the pedestal for 180º(see Figure 2-3) and remove the

level pedestal board 8. 5. Remove threeφ3steel balls 7. 6. Grasp the foot screw 4 and use a plate to screw the bearing

backing nut 6. 7. Drip a little vacuum pump oil between the bearing backing

nut 6 and the level bearing 5. 8. Install threeφ3steel balls 7 and level base boards 8 one by

one. 9. Turn the pedestal for 180º and install the elastic washer 3. 10. Install the base backing nut 2 and use a plate to screw it

tight. 11. Rotate the screw 1 anticlockwise and lock the wrench

handle.

II. Shaking of the foot screw

Shaking of the foot screw is caused by loosening of the guide

23

sleeve. The maintenance procedures are as follows: 1. According to the operations 1-5 in I. Sliding of the level

press board above, remove relevant parts(see Figure 2-3) 2. Grasp the level hand wheel 3 and use a plate to remove the

backing nut 7 of the level bearing (see Figure 2-4). 3. Remove three bearing washers 6 and three level bearings 5. 4. Remove the level press board 4. 5. Rotate the foot screw 3 clockwise and slide it down until

it is close the guide sleeve 2 as much as possible, then adjust the foot screw 3, allowing twoφ3 holes on the foot screw to be aligned with the groove of the guide sleeve 2.

6. Loose the cone-point set screw 1 and use a plate to screw the guide sleeve 2.

7. Screw the cone-point set screw 1, fasten the guide sleeve 2 and seal it with varnish.

8. Install the level press board 4, three level bearings 5 and three bearing backing nuts 6.

9. Repeat operations 6-11 in I. Sliding of the level press board above.

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5

6

7

4

3

1

2

（Figure 2–4）

1. cone-point set screw 2. guide sleeve 3. foot screw 4. level press

board 5. level bearing 6. bearing washer 7. bearing backing nut

III. Tightness of the foot screw

After long term usage of the instrument, the handwheel may become tight or the frame may become flexible due to volatilization of grease on the handwheel. The mainteance procedures are as follows:

1. Remove relevant parts according to operations 1-5 in I. Sliding of the level press board and operations 2-5 in II. Shaking of the level handwheel above.

2. Loose cone-point set screw 1 (see Figure 2-4) and use a plate to rotate the guide sleeve. Remove the level handwheel set from the pedestal.

3. Remove the split washer 3 (see Figure 2-5).

25

4. Rotate the level handwheel 1 and remove it from the guide sleeve 2.

5. Wash the thread section of the level handwheel 1 with gasoline (see Figure 2-5) (if the thread section of the elastic screw in the guide sleeve is dirty, the whole component can be washed, but it must be dried completely after washed), and smear handwheel grease at the thread sections of the guide sleeve and the level handwheel.

2 31

(Figure 2-5)

1. level handwheel 2. guide sleeve 3.split washer

6. Screw the level handwheel 1 into the guide sleeve 2 and install the split washer 3.

7. Screw the level handwheel set into the pedestal. 8. Repeat operations 5-9 in II. Shaking of the level

handwheel above.

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2.6 Common faults of the slide pedestal I. Malfunction of the locking mechanism of the pedestal

Fasten the pedestal lock handwheel 1 (see Figure 2-6) and parallel move the alidade 4 to make sure that the alidade 4 can still slide relative to the slide pedestal 3. The fault is caused by malfunction of the locking mechanism of the pedestal, which causes the alidade can not be locked.

The maintenance procedures are as follows: 1. Loose the two M2 cone-point top threads 2 on the pedestal

lock handwheel 1 (see Figure 2-6). 2. Screw the pedestal lock handwheel 1 clockwise and fasten

the alidade 4. Push the alidade 4 for checking to make sure no displacement relative to the slide pedestal 3 will occur.

3. Tighten up the two M2 cone-point top threads 2. 4. Loose the pedestal lock handwheel 1 and push the alidade 4;

the alidade should be parallel moved freely.

4

3

2

1

(Figure 2-6)

27

1. lock handwheel 2. M2 cone-point top thread

3. slide pedestal 4. alidade

II. Sliding of the level press board Sliding up and down of the level press board, which may

cause the plate level can not swing to a fixed level, is resulted from loosening of the backing nut of the level bearing. First we can separate the slide pedestal and the alidade, then clear the pedestal fault. (I) Separate the slide pedestal from the alidade (see Figure 2-7).

1. Turn the instrument to let the slide pedestal 1 upward. 2. Loose the lock handwheel 3. 3. Insert the screwdriver through the big hole at the center, remove

the three M3 sunk screws 2 connecting the slide pedestal 1 and the middle-lower housing of the alidade 4, and take down the slide pedestal 1. In order to remove the screws, we can move the slide pedestal1 to make the center big hole at a position where it is easy to remove the screws.

1

2

3 4

28

(Figure 2-7) 1. pedestal 2. M3 sunk screw 3. lock handwheel 4. alidade

(II) Fault elimination of sliding up and down of the level press board

1. Use a plate to remove the base backing nut 1.

3

5

4

67

1

2

（Figure 2-8）

1. base backing nut 2. elastic washer

3. level handwheel 4. level bearing

5. bearing backing nut 6. φ3 steel ball

7. level base board

2. Take down the elastic washer 2. 3. Turn the pedestal for 180º and take down the level base

board 7. 4. Take down the threeφ3 steel balls 6. 5. Grasp the level handwheel 3 and use a plate to screw the

bearing backing nut 5. 6. Drip a little vacuum pump oil between the backing nut 5 of

29

the level bearing and the level bearing 4. 7. Install threeφ3 steel balls 6 and the level base board 7 in

turn. 8. Turn the pedestal at 180º and install the elastic washer 2. 9. Install the base backing nut 1 and use a plate to screw it

tight. 10. Turn the instrument and install the slide pedestal and three

M3 sunk screws (see Figure 2-8). Firmly connect the slide pedestal and the middle-lower housing of the alidade 4.

III. Tightness of the foot screw

After long term usage of the instrument, the foot screw may become tight or the frame may become flexible. The maintenance procedures are as follows:

1. Rotate the foot screw 4 of the slide pedestal 5 to let the φ2.5 hole 1 on the foot screw 4 be aligned with theφ2.5 hole 2 on the pressing sleeve 3 (see Figure 2-9).

5 4 3 2 1

(Figure 2-9)

30

1. φ2.5 hole 1 on foot screw 2. φ1.5 hole 3. pressing sleeve

4. footscrew 5. slide pedestal

2. Use a special plate to rotate the pressing sleeve. If the foot screw is tight, rotate the pressing sleeve anticlockwise; if the frame of the foot screw is flexible, rotate the pressing sleeve clockwise.

3. After it is properly adjusted, turn the three foot screws one by one and make sure that the three foot screws can be easily and gently rotated and the frame can not be moved.

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Chapter III Fault Maintenance of Angle Measurement

3.1 Introduction about electrical circuit signal of angle measurement The angle measurement part of electronic theodolite consists of horizontal angle measurement which is of diameter reading (two sensors) and vertical angle measurement which is of single-sized reading (one sensor), and each sensor outputs two ways of sine waves which are taken as the basic signal for angle measurement through further adjustment and treatment on main board and such basic signal is the original signal of electronic angle measurement (six ways of sine waves) which directly influences the results of angle measurement, so the requirements for the wave form is relatively high and precise adjustment is needed. One way of zero-crossing pulse will be added to vertical angle measurement part and the zero-crossing voltage signal should be adjusted for the angle measurement circuit accordingly.3.2 Cause and maintenance of fault of not being able to start-up I. Insufficient battery power

Multimeter is switched to DC voltage position to check the voltage of the battery case, whose voltage shall be greater than 6.5V. If less than 6.5V, it shows that battery power is not adequate. In this case, the battery case shall be connected with the dedicated charger and then connected with the power supply of the charger. When the indicator indicates red, charging starts. The indicator will indicate

32

green when battery is fully charged. Power supply shall be cut off before disconnecting the battery case. Then the battery case is installed to check whether instrument can start up.

This charger is a quick charger that is able to complete charging in 4 hours quickly with power reaching 80%. If battery needs to be fully charged, it needs 2 to 4 hours’ trickle charging. Attention shall be paid to that charging time shall not exceed 24 hours.

II. Loose connection of power wire

If the battery case is determined as fully charged by above method, and instrument still can not start up, power wire shall be checked for linking condition.

Remove six M2.5 screws on the left fixed cover board to open the left cover board. Then disconnect plug 2 of buzzer on angle measuring mainboard 1 (see Figure 3-1) to take off the left cover board. When the instrument is turned on, voltage meter is used to measure voltage of pins on the four-core socket of power wire of the angle measuring mainboard 1 (see Figure 3-1). The two pins in the middle of the four-core socket are positive and another two pins are negative. The voltage shall be greater than 6.5V. If voltage is zero or intermittent, it may be caused by loose connection of power wire or electrode of the right cover board.

33

-+-

1

2

(Figure 3-1) 1. Angle measuring mainboard 2. Plug of buzzer

(1) Loose connection of power wire (see Figure 3-2)

Loose connection of power wire may be caused by turnoff of power wire or that wire 3 and contact 2 are not connected well because of cold joint. First, you shall determine whether lead is open due to extrusion of power wire. If power wire has no fault, but power wire and contact 2 are not well connected, they shall be rewelded firmly. During welding, battery case can be installed on right cover board 6, so that contact will be pushed out and higher than cover 1. In this way, cover will not be burned during welding. Welding point shall be smaller than the hole of the cover. After welding, you shall check whether welding is reliable, contact rebounds freely and without block or connection with contact of battery is reliable.

When welding power wire, attention shall be paid to that

34

welding position of negative and positive poles shall be correct. The black wire shall be welded to contact 2 and the red one shall be welded to contact 5, otherwise, the serious result that angle measuring mainboard may be burned when instrument is turned on may be caused.

43

2

1

5

6

(Figure 3-2) 1. cover 2. contact (negative) 3.power wire (black) 4. power wire (red) 5.

contact (positive) 6. right cover board

(2) Loose connection of electrode After using for a long time, the instrument may not be able to

rebound due to dust and oil deposited at the electrode, thus resulting in that good connection with contact of battery case can not be ensured.

Figure 3-3 shows electrode structure diagram of this series of electronic theodolite. When maintaining, power wire can be removed by welding to remove four cross recessed self-tapping screws 1. Then cover 2 and contact spring 3 and contact 4 can be

35

removed. These parts shall be cleaned by using gasoline and then reassembled. Lubricant shall not be applied when assembling.

1 2 3 4

5

(Figure 3-3) 1. cross recessed self-tapping screw 2. cover 3. contact spring 4. contact 5. right baffle plate III. Fault of electronic compensator

When there is no problem with battery power and connection of power wire, and the instrument still can not start up, power supply shall be cut off. Remove four M2.5 screws on fixed angle measuring mainboard to separate angle measuring mainboard from bracket of instrument. Remove plug of electronic compensator from angle measuring mainboard 7 (see Figure 3-4) and then check whether the instrument is able to start up or not. If it is able to start up, it shows that electronic compensator has fault. It is necessary to replace electronic compensator and calibrate new electronic compensator (for replacement and calibration methods, see3.4

36

Fault maintenance of electronic compensator).

4

2

1

7

3

5

6

(Figure 3-4) 1. socket of power wire 2. socket of display 3. socket of electronic compensator 4. socket of vertical simulator 5. socket of level simulator 6. US232 socket 7. angle measuring mainboard IV. Fault of LCD

When electronic compensator has no problem and instrument still can not start up, then cut the power supply, and remove the plug of display on the side of normal telescope on the angle measuring mainboard. Figure 3-4 shows the position of the plug. Check whether instrument can start up. If not, power supply shall be cut off, and plug of display on the side of reverse telescope on the angle measuring mainboard shall be removed. Plug of display on the side of normal telescope shall be inserted on the angle measuring mainboard. Figure 3-4 shows the position of inserting. After installation, check whether instrument can start up. If it still

37

not, it can be determined that the angle measuring mainboard has a fault. It is necessary to replace the angle measuring mainboard.

During the above examination, if instrument can start up when display on one side is plugged, but can not start up when display on another side is plugged, it can be determined that there is a fault with display on this side or the data wire of the display. At this time, four M2 screws on the fixed display can be removed after power supply is cut off. Data wire of display on the side in which instrument can start up is removed and reassembled on another side. Check whether instrument can start up. If not, it can be determined that display on this side has a fault. If instrument can start up, it shows that data wire has a fault. Display or data wire can be replaced according to the fault.

In addition, after using for a long time, LCD may not display or display incomplete things, or its key fails. New display or data wire can be replaced according to the fault. When replacing, remove four M2 screws on the fixed display and connector of display and angle measuring mainboard. New display or data wire is connected with angle measuring mainboard. Connection shall be reliable and in the correct position. When instrument can start up, the display shall be installed on the bracket of the instrument. Four M2 screws shall be secured firmly.

V. Fault of the Mainboard

If determined in the aforesaid four examinations that the malfunction parts was the angle measuring mainboard, it shall be replaced by a new one. Before replacing, the power shall be cut off

38

first and then every connector on the angle measuring mainboard shall be removed one by one (see Figure 3-4).

Debug the angular measurement electrical signal of the two horizontal simulators and the single vertical simulator (see also 3.4 Maintenance of the Malfunction in Angular Measurement) and zero-crossing voltage (see also 3.3 Non Display of the Zero Position of the Vertical Angular).

After the angular measurement electrical signal of the two horizontal simulators and the single vertical simulator have been debugged well, the new angle measuring mainboard shall be replaced and installed. While installation, every connector shall be plugged in and connected to the corresponding socket of the angle measuring mainboard. The position of the connectors shall be correct and the connection of which shall be reliable. After the connectors are examined to be correctly installed, the angular measurement board shall be mounted on the support, and then fasten by four M2.5 screws.

When connecting the power, the connection of positive and negative pole shall be correct, otherwise the angle measuring mainboard might be damaged again.

After replacing, the angle measuring mainboard shall be debugged, calibrated and set as follows:

1. Debug the vertical zero-crossing voltage (see also 3.3 Non Display of the Zero Position of the Vertical Angular).

2. Re-calibrate the compensator (see also 3.5 Maintenance of the Electronic Compensator Malfunction).

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3.3 Non Display of the Zero Position of the Vertical Angular

Leveling the instruments, and start the instrument. When the screen displays the information of setting the zero position of the vertical angular, you shall rotate the telescope in circles to pass zero at the vicinity of the 90° of the vertical angular circle-left (direct position of telescope). The angular value of the vertical angular on the screen shall be displayed. If the screen continuously displays: “SET 0” (see Figure 3-5), it means that the instruments have the problem of not crossing zero. If such circumstance happens, the zero-crossing electrical signal and zero-crossing voltage of the angle measuring mainboard shall be measured and be debugged again.

Adjustable electric resistance WR9 (see Figure 3-6) was installed on the angle measuring mainboard of the instruments produced in the early stage, so the adjustment of the zero-passing voltage shall be carried out on the angle measuring mainboard. The adjusting of the zero-passing voltage of the instruments currently produced has already been adjusted by software. You shall following the methods introduced below, to adopt corresponding methods to adjust the zero-crossing voltage of different instruments.

40

06–03–20 14：38

VA S E T 0

HA

R180°10′30″

(Figure 3-5) I. The method of using adjustable electric resistance to adjust the zero-crossing voltage:

WR9

P3P4P2 P1

P6 P5

P8P1

1

Latt

ice

1

(Figure 3-6)

1. Angle measuring mainboard 1. Shut down the instrument, remove the six M2.5 screw on

the left cover board of the fixed instrument, then open the left cover board, pluck off the buzzer plug on the angle measuring mainboard and remove the left cover board.

2. Switch on the instrument, use the oscillograph (select mode A, a sensitivity of 500mV and a scanning speed of 1mS for the

41

oscillograph) to detect the waveform of the P8 point of the angular measurement board (see Figure 3-6), and at the same time rotate the telescope at the vicinity of the 90° of the vertical angular circle-left, by doing so, the oscillograph shall display zero-crossing pulse showing in Figure 3-7. The minimum voltages (Vs) of the zero-crossing pulse shall pass 0.8V, and the amplitude of the zero-crossing pulse shall be Vn – Vs ≥ 0.5V.

3. Use the oscilloprobe to detect the waveform of the P11 point (see Figure 3-6) of the mainboard, and the Figure displayed in the oscillograph shall be a direct current level Va (see the Va in Figure 3-8). The corresponding relationship with the zero-crossing pulse in Figure 3-7 shall be that showing in Figure 3-8. When rotate the telescope to not passing zero, the direct current level Va shall be lower than the valley point Vs (see Figure 3-8) of that of zero-crossing pulse).

1: ＞500mV 2：＞500mV

A ＞1mS

Vs

Vn

1: ＞500mV 2：＞500mV

A ＞1mS

VnVaVs

1


42

1. Zero-crossing pulse

4. Use noninductive screwdriver to slightly adjust the

potentiometer WR9 on the angle measuring mainboard and simultaneously observe the oscillograph. The position of the direct current level Va shall move up and down, you should adjust the direct current level Va to 1/2 (Vn-Vs) + Vs (see Figure 3-8).

5. Shut down the instrument and restart it, rotate the telescope at the vicinity of the 90° of the direct position of telescope (circle-left) to test if the instruments can cross zero normally. If the instruments can cross zero normally, you shall re-calibrate the index error of the vertical circle, and if the index error is not qualified, you shall lower the direct current level Va a bit. But you shall ensure that the direct current level Va shall be higher than the lowest valley point of zero-crossing pulse for 0.3V. For the calibration method of the index error of the vertical circle, see 3.6 Setting of the index error, collimation error and the zero point error of the compensator.

6. Shut down the instrument; insert the plug of the buzzer on the left cover board into the two-core socket on the angle measuring mainboard. Then install the left cover board, the six M2.5 screw, and at last fasten the left cover board.

II. Method to adjust the zero-crossing voltage with software

1. Shutdrown, dismount the six M2.5 screws on the left cover board of the fixed instrument, open the left cover board, remove the

43

plug of the buzzer on the angle measuring mainboard, and then remove the left cover board.

2. Press and hold both [OSET] and [ ] keys simultaneously (see Figure 3-9), and then press [ ] key to start up; Display screen displays “FAC” and then enter the instrument accuracy setting mode after about 2 seconds. And then press the SFT key to enter the factory pattern, as shown in Figure 3-9.

DIST S/H/V

OSET R/L

REP

HOLD V/%

SFT

REC

(Figure 3-9)

3. Press both [ ] and] L/ R ] keys simultaneously (see Figure 3-9), interface as shown in Figure 3-10 will be displayed on the display screen, and then entering zero-crossing voltage adjustment mode. Wave shape of P8 (see Figure 3-11) on the angle measuring mainboard can be inspected by the oscillograph (switch the oscillograph to Mode A with 500mV sensitivity and 1mS sweep speed), and at the same time, telescope shall be rotated at such near the elevating angle 90°of the left side of the disc; Zero-pulse as shown in Figure 3-7 shall be displayed by the oscillograph.

44

Minimum voltage of this zero-pulse shall be more than 0.8V, with a pulse amplitude Vn–Vs≥0.5V.

06–03–20 14：38

82

1.58

(Figure 3-10)

P3P4

P1P2

P5P6

P8

Latt

ice

P11

1

(Figure 3-11)

1. The angle measuring mainboard

45

4. Press [V / % ] , inspect the wave shape of P11 (see Figure 3-11) on the the angle measuring mainboard by the oscillograph probe, DC voltage level Va (see Figure 3-11) shall be displayed by the oscillograph, relative relationship between which and the zero-pulse as shown in Figure 3-7 is shown in 3-8. When rotation of the telescope is not zero, the DC voltage level Va is less than the valley point Vs of the zero-pulse wave (see Figure 3-8).

5. in case that the zero-crossing voltage Va is too low or too high (although the too high zero-crossing voltage Va is able to be zero, it may cause a overproof phenomenon of the vertical index error.), it is able to modify the software parameter by press keys on the panel as shown in Figure 3-9 to change the zero-crossing voltage Va in order to meet the requirement. [L / R ] and [V / % ] keys on the panel are for crude regulation, wherein [L/R] is the rise key and [V/%] is the lower key. Upon press [L/R] or [V/%] a time, the zero-crossing voltage Va will increase or rise or lower about 100mV. Observe the oscillograph at the same time until the position DC voltage level Va moves upward and downward. [OSET] and [HOLD] keys on the panel are for accurate adjustment, wherein [OSET] is the rise key and [HOLD] is the lower key. Upon press [OSET] or [HOLD] a time, the zero-crossing voltage Va will increase or rise or lower about 20mV. DC voltage level V shall be adjusted until it reaches to 1/2 (Vn–Vs）+Vs (see Figure 3-8).

6. Press [ ] to verify, the display screen will return to the interface shown in Figure 3-9.

7. shutdown and restart up, telescope shall be rotated at such

46

near 90º of the telescope direct (left side of the disc), to check the instrument to be bale to be zero normally or not. If so, re-regulate the index error of the vertical circle, in case of an unqualified index error, it is good to lower DC voltage level Va. But it shall be ensured that such DC voltage level Va is 0.3V more than the valley point Vs of the zero-pulse. Method to regulate the index error of the vertical circle is shown in 3.6 index error and collimation error compensator zero point error setting.

8. Shutdown, insert the plug of the buzzer on the left cover board in the twin core socket on the angle measuring mainboard. Mount the left cover board, tight the six M2.5 screws and fix the left cover board.

III. Method to adjust the zero-crossing voltage with software without any oscillograph

When maintained, in case of no oscillograph, as to the instrument whose zero-crossing voltage is adjusted with software, it can be adjusted with the following methods. Note: after the adjustment, be sure to carefully check the zero-crossing voltage to be adjusted to the ideal position or not according to the below check methods, so as to ensure the use accuracy of the instrument.

1. Press and hold both [OSET] and [ ] keys simultaneously (see Figure 3-9), and then press [ ] key to start up; If display screen displays “FAC”, it will enter the instrument accuracy setting mode after about 2 seconds. And then press the SFT key, if the

47

display is as shown in Figure 3-9, zero-crossing voltage of such instrument is able to be adjusted with the software.

2. Press and hold both [ ] and [L / R ] keys simultaneously (see Figure 3-9), if the display on the display screen is as shown in Figure 3-12, number in the third line in the Figure is value of the zero-crossing voltage Va, that is 1.10V.

06–03–20 14：38

56

1.10

(Figure 3-12)

3. Press [L/R] on the panel shown in Figure 3-9 once, the zero-crossing voltage Va will rise about 100mV, value of zero-crossing voltage Va in Figure 3-12 will change from 1.10V to 1.20V.

5. Telescope shall be rotated at such near 90º of the telescope direct (left side of the disc), to check the instrument to be able to be zero normally or not. If not, press [L/R] once again, zero-crossing voltage Va will rise about 100mV again, value of zero-crossing voltage Va in Figure 3-12 will change from 1.20V to 1.30V.

6. Telescope shall be rotated at the telescope direct (left side of the disc), to check the instrument to be able to be zero normally or

48

not. If so, “0SET”will appear before the number in the second line, as shown in Figure 3-13. (If not, check the instrument to be able to be zero normally or not after higher the zero-crossing voltage.)

06–03–20 14：38

OSET 66

1.30

(Figure 3-13)

7. Press [L/R] on the panel shown in Figure 3-9 three times, the zero-crossing voltage Va will rise about 300mV, value of zero-crossing voltage Va in Figure 3-12 will change from 1.30V to 1.60V.

8. Press the lighting key to verify, display screen will return to the interface shown in Figure 3-9. Shutdown.

9. Telescope shall be rotated at such near 270º of the telescope reverse (right side of the disc), to check the instrument to be able to be zero normally or not, under normal condition, it must not be zero. In case it is able to be zero, indicating that the zero-crossing voltage Va is too high, so zero-crossing voltage Va shall be lowered 100 mV as per the above-mentioned method.

49

Recheck until telescope can be rotated to zero under the telescope direct condition and can not be rotated to zero under the telescope reverse condition.

10. Being the telescope direct condition, and object lens of the telescope located over 90 º, start up , telescope shall be rotated top-down to be zero. Cross wire of the telescope collimates the collimator tubes and divides point A on the board, read the latitude value, and shutdown. Object lens of the telescope located under 90 º, start up, telescope shall be rotated down -top to be zero. Cross wire of the telescope still collimates the collimator tubes and divides point A on the board, read the latitude value. Compare the two values; difference between the two values shall not exceed 3″. If so, indicating that the zero-crossing voltage Va is too high, so zero-crossing voltage Va shall be lowered 100 mV as per the above-mentioned method. Recheck until meet the requirement.

11. shutdown and restart up, telescope shall be rotated at such near 90º of the telescope direct (left side of the disc), to check the instrument to be bale to be zero normally or not. If so, re-regulate the index error of the vertical circle, in case of an unqualified index error, it is good to lower DC voltage level Va. Method to regulate the the index error of the vertical circle is shown in 3.6 index error and collimation error compensator zero point error setting.

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3.4 Fault Maintenance of the Angle Measurement Level the instrument, turn it on, and rotate the telescope

passing zero. After rotating the vertical shaft and the cross shaft respectively 3 circles, observe point A on the parallel plain tube reticule, record the values of the vertical angle and the horizontal angle; after rotating the vertical shaft and the cross shaft respectively 2 to 3 circles, still observe the object point A, read the value variation between the vertical angle and the horizontal angle, which shall not surpass 5″. If the value variation surpasses 5″, the repetitiveness of the angle measurement is proved to be poor.

Slightly move the horizontal or vertical handwheel, and observe the indicating value of the horizontal or vertical angle, which shall be steadily increased or decreased according to the minimum indicating value united 1″ (the angle measurement shown shall be set of 1″). If there incurs any abnormal conditions, it is proved that there are hop problems on the horizontal or vertical angles.

I. Fault of Horizontal Angle Measurement

Through being used for a long time, the instrument might incur problems such as poor repetitiveness or hop on the horizontal angle measurement. When there are such faults, the horizontal angle signal of the angle measuring mainboard shall be measured and re-debugged.

Remove the 6 M2.5 screws fixing the left cover board of the instrument, then, open the left cover board. Pull down the buzzer plug on the angle measuring mainboard, and remove the cover

51

board, then the angle measuring mainboard can be visible. The electrical signals of the electronic theodolite angle measurement is consisted of 6 ways of sine wave signals, and the measurement points include the test points P1~P6 on the angle measuring mainboard (see Figure 3-18, wherein, the angle measuring mainboard is drawn in accordance with the old structure, and the new angle measuring mainboard has no potentiometer any more, others are the same with the picture.).

WR9

P3P4P2 P1

P6 P5

P8P1

1

Latt

ice

1

(Figure 3-14) 1. Angle measuring mainboard

Figure 3-18 Instructions to the test points

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P1 Horizontal angle measurement signal test pointP2 Horizontal angle measurement signal test pointP3 Horizontal angle measurement signal test pointP4 Horizontal angle measurement signal test pointP5 Vertical angle measurement signal test point P6 Vertical angle measurement signal test point P8 Zero-crossing pulse test point

P11 Zero-crossing voltage test point

Angle measurement electrical signal of each test point shall be

respectively detected by the oscillograph (the oscillograph shall be Mode A, with a sensitivity of 500mV and a scan speed of 1mS). Before the detection, the accuracy and zero mark of the oscillograph shall be calibrated.

Rotate the alidade, and detect the waveform of the angle measuring mainboard test point P1~P4 (see Figure 3-14) with the oscillograph probe, which shall be standard sine single waveform (see Figure 3-15), and the waveform shall conform to the following requirements:

53

1: ＞500mV 2：＞500mV

A ＞1mS

1

(Figure 3-15)

1. Sine wave

A: The DC level is 2.5V±0.02V B: The amplitude of the AC part shall be 1.2V±0.2V C: Amplitude difference between the two horizontal angle

measurement electrical single P1 and P2 ＜0.1 V Amplitude difference between the two horizontal angle

measurement electrical single P3 and P4 ＜0.1 V

If the above requirements can not be satisfied, it can be adjusted in accordance with the following steps:

1. Turn off the instrument and disconnect the power. 2. Remove the 4 M2.5 screws fixing the angle measuring

mainboard, and pull off the horizontal simulator plug required to be adjusted on the angle measuring mainboard (see Figure 3-4), then put it on six-core socket of the special debugging box. Wherein, if there is oversize on Point P3and P4 (see Figure 3-14) electrical

54

signal, the long-line horizontal simulator is required to be adjusted. If there is oversize on P1 and P2 (see Figure 3-18), the long-line horizontal simulator is required to be adjusted. To adjust the short-line horizontal simulator, the right baffle plate is required to be removed.

CP 1 CP 20V

1 3

2

(Figure 3-16) 1. Test box 2. Power plug 3. Six-core socket

55

1

WR 4WR 3WR 2WR 1

(Figure 3-17)

1. Horizontal simulator

3. Power supply on the special debugging box is DC 5V±

0.02V. The oscillograph shall be Mode A, with a sensitivity of 500mV, and the probe attenuation shall be Gear X1, which shall be spliced on the socket CP1 of the special debugging box (see Figure 3-16). Earth wire of the oscillograph shall be connected to the special debugging box (⊥). Rotate the alidade and observe the sine wave signal of the oscillograph. Adjust the potentiometer on the horizontal simulator with an inductionless screwdriver (see Figure 3-17), thereby making the amplitude voltage and the central voltage of the one output of the sine wave signal (see Figure 3-17) conform to the technical requirements.

Wherein, potentiometer WR2 and WR3 (see Figure 3-17) respectively change the amplitude voltage of the two way sine

56

waves. Potentiometer WR1 and WR4 (see Figure 3-21) respectively change the central voltage of the two way sine waves.

When debugging, pay attention that the potentiometer can not be adjusted at the limit position, otherwise, the amplitude voltage and the central voltage will uneasily to change. Moreover, when rotating the alidade and observing the variation of the amplitude voltage, there are two abnormal conditions, one is the variation of the amplitude voltage surpasses 500mV. In this way, it may cause horizontal hop. The reason is that there is tackless between the horizontal comb rack and the grid disk (the above grating disk) or between the horizontal comb rack and the positioning disk, thereby causing clearance variation of the grating disk. It can be tested with a feeler of 0.02mm, from 4 directions of the all-around, which shall be tested once per 90°, and the feeler shall be plugged in between the two grid disks. If there is one place can not be plugged, the clearance between the two grid disks can be tested to be smaller. As it required to be dismantled with a tool, it shall be returned to the factory for repair.

Another condition is: when observing the variation of the amplitude voltage, there is up and down or left and right hop on the sine wave. This is because there is oil stain, fingerprint or foreign matter on the grating disk. In the two horizontal gating disks, the lower one the main grating disk, if disk surface is dirty, the sine wave will hop, and when the hop surpasses 200mV, it will cause horizontal hop. Dip some mixed liquor (aether 70%, ethanol 30%) with the absorbent cotton to clean the surface of the grating disk.

4. Probe CH1 shall be changed to be plugged on socket CP2 of

57

the special debugging box. Rotate the alidade, and the oscillograph will display the sine wave of another way of electrical signal of the horizontal simulator, as shown in Figure 3-15. The amplitude voltage and central voltage of this sine wave shall conform to the above technical requirements.

5. If the electrical signal amplitude voltage and central voltage output by a horizontal simulator can not achieve the technical requirements, the voltage can be adjusted in accordance with the above methods.

6. After the horizontal simulator is adjusted, turn off the instrument and disconnect the power. Put the six-core plug of the long and short horizontal simulator into the respective position on the angle measuring mainboard (see Figure 3-4). Then, test the horizontal angle measurement electrical signal of the angle measuring mainboard.

7. Put on the angle measuring mainboard, and fix it with 4 M2.5 screws; put the buzzer plug into the angle measuring mainboard, install the left cover board, and fix it on the support with 6 M2.5 screws.

Ⅱ. Fault of vertical angle measurement

Measuring the difference of repeatability or hop of angle at vertical angle shall firstly inspect the electric signal of vertical angle measurement on angle measuring mainboard, with the method of which is the same as that of horizontal electric signal (see above), the test points are P5 and P6 in the Figure 3-18.

Waveform shall meet the following requirements:

58

A: DC level is 2.5V±0.02V B: Partial amplitude value of AC is 1.2V±0.2V C: The amplitude difference of electric signal of vertical angle

measurement between P5 circuit and P6 circuit is less than 0.1 V

WR9

P3P4P2 P1

P6 P5

P8P1

1

Latt

ice

1

(Figure 3-18) 1. Angle measuring mainboard

It can adjust according to the following procedures if the waveform can not meet the above requirements:

1. Tear down four M2.5 of cross recess head screws on the fixed angle measuring mainboard and remove the angle measuring mainboard.

2. Unplug the plug of vertical stimulator from angle measuring mainboard (see Figure 3-4) and insert into six-core socket of dedicated debugging box.

3. DC power supply from dedicated debugging box is 5V±

0.02V. Oscillograph is selected as X-Y mode with sensitive degree

59

of 500mV. The two attenuating probes are selected as X1 gear, respectively inserting into CP1and CP2 sockets of dedicated debugging box (see Figure 3-16). The earth wire of oscillograph connects with dedicated debugging box.

4. Inspect with a feeler ruler about 0.02 mm at one time for four directions every 90°, the feeler ruler shall insert into the clearance of two grating disks, with roughly same clearance at each place. If one place can not be inserted, then it can be judged that the clearance between two grating disks at this place has become smaller.

12

2

3

(Figure 3-19) 1. Left bearing φ6 bore 2. M3X5 internal hexagonal top thread

3. Adjusting screw

5. Turn the lateral axis, aim the left bearing φ6 bore 1 (see Figure 3-19) at internal hexagonal top thread 2 one by one, counterclockwise spin a round for each M3X5 internal hexagonal

60

top thread 2 (totally 4) (as Figure 3-19, two more on the opposite of mirror).

6. Turn the lateral axis to make the left bearing φ6 bore 1 (see Figure 3-23) aim at the adjusting screw 3. Turn the telescope back and forth with slow and constant speed at small angle, and observe the Lissajous Figures on oscillograph at the same time. Slightly adjust the adjusting screw 3 with a screwdriver (see Figure 3-19). There are four adjusting screws with oriented angle of 90°to each other, the amplitude voltage can be changed by respectively adjusting the clearance between two grating disks at four directions of up, down, left and right. Clockwise turning the adjusting screw close to this place can increase the clearance between two grating disks of this place to decrease the amplitude voltage. The counterclockwise turning can reduce the clearance between two grating disks to increase the amplitude voltage. Turn the lateral axis for a round to observe the Lissajous Figures on oscillograph, with the amplitude value shall be 500-1500mV (see Figure 3-20).

61

A ＞1mS

1: ＞500mV 2：＞500mV

A ＞1mS

1: ＞500mV 2：＞500mV

Vs

Vn

1 1


1. Lissajous circle 1. Zero crossing pulse

If phase difference is a little bit great when adjusting, the clearance between grating disks on the left and right can be adjusted to reduce the phase. After regulating, the clearance between grating disks shall be inspected with feeler ruler, which shall be conform to the above requirements.

When observing the Lissajous Figures on oscillograph, if the Lissajous Figures jumps up and down or left and right, it may be owing to the greasy dirt, finger mark or foreign matter on the surface of grating disk. In the two vertical grating disks, the outer one is the main grating disk. If its surface is dirty, it may cause the electric signal to jump and, more seriously, lead to the vertical hop. The surface of grating disk can be cleaned with absorbent cotton wetting appropriate mixed liquor (70% of aether and 30% of ethanol).

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In addition, turn the lateral axis a round, and when observing the Lissajous Figures on oscillograph, the Lissajous Figures will has change in respect of size. The change of amplitude value shall be less than 500mV. If it exceeds 500mV, it may cause the hop of vertical angle measurement, which is due to the greater axial hop amount of lateral axis after long time use of instrument. Because it needs special tools to remove, it shall be returned to factory for repair.

WR5 WR6 WR7 WR8

1

(Figure 3-22) 1. Vertical simulator

7. Oscillograph is selected as A mode, the probe CH1 is changed to insert zero crossing socket (V0）of dedicated debugging box (see Figure 3-16), turn the telescope near the right angle of face mirror ( left of disk), oscillograph shall show zero crossing pulse as Figure 3-21. The amplitude of this zero crossing pulse of Vs-Vn shall be not less than 0.5V.

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8. Oscillograph is selected as “A” mode with sensitive degree of 500mV. The attenuating probe is selected as X1 gear, inserting into CP1 socket of dedicated debugging box (see Figure 3-16). The earth wire of oscillograph connects with dedicated debugging box.

1: ＞500mV 2：＞500mV

A ＞1mS

1

(Figure 3-23)

1. Sine wave

Turn the lateral axis back and forth and observe the sine wave signal on oscillograph. Adjust the potentiometer of vertical stimulator with noninductive screwdriver (see Figure 3-22) to make the amplitude voltage and center voltage of sine wave signal ( see Figure 3-23) outputted by the first circuit meet the following technical requirements:

A: DC level is 2.5V±0.02V B: partial amplitude value of AC is 1.2V±0.2V

In Figure 3-22: potentiometers of WR6 and WR7 can respectively change the amplitude voltage of sine wave on two circuits.

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Potentiometers of WR5 and WR8 can respectively change the center voltage of sine wave on two circuits. Take care not to adjust the potentiometer to the limit position when adjusting, thus the amplitude voltage or center voltage is not easy to change.

9. Probe CH1 is changed to insert into CP2 socket of dedicated debugging box. Turn the lateral axis, oscillograph shows the sine wave of electric signal on another circuit of vertical stimulator, as described in Figure 3-23. According to the above adjusting method, make the amplitude voltage and center voltage of sine wave on this circuit achieve the above technical requirements. Apart from satisfying the above technical requirements, the amplitude difference of electric signal of vertical angle measurement on two circuits shall be less than 0.1 V.

10. After the completion of debugging, insert the six-core plug of stimulator into the corresponding position of angle measuring mainboard (see Figure 3-4).

11. Recheck the electric signal of vertical angle measurement of angle measuring mainboard (test points of P5 and P6 in Figure 3-18), if there is no mistake, debug the zero crossing electric signal, for the debugging method to which, see3.2 no display of vertical angle of zero position.

12. Insert the buzzer plug into the angle measuring mainboard and amount left cover board and fix on the support with six M2.5 screws.

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3.5 Fault maintenance of electronic compensator

Ⅰ. Change of electronic compensator

1. Dismantling six M2.5-screws fixing the left cover and disconnecting buzzer plugs from the angle measuring mainboard is for taking down the left cover.

2. Dismantling four M2.5-cross recessed pan head screws is for taking down the angle measuring mainboard. The compensator plugs are disconnected from the angle measuring mainboard (see Figure 3-4).

1

2

3

4

(Figure 3-24) 1. M3-screw hole on the bracket, 2. Compensator,

3. Φ3 washer, 4. M3-screw

3. Dismantling six M2.5-screws fixing the left cover on the instrument is for taking down the left cover.

4. Dismantling two M3-screws 4 and twoΦ3 washers 3 for

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fixing the compensator 2 (see Figure 3-24) is for taking down the compensator 2.

5. The new electronic compensator will be assembled on the brackets by firmly fixing two M3-screws 4 and twoΦ3 washers 3.

6. Passing from one side of bracket without fitting plate level to left side of bracket, the 6-way plug of compensator will be connected to the compensator socket on the angle measuring mainboard (see Figure 3-4).

7. The angle measuring mainboard will be fixed firmly on the bracket by 4 M2.5- cross recessed pan head screws.

8. The buzzer plug will be connected to the angle measuring mainboard, and the left cover will be fixed firmly by 6 M2.5-screws.

After changing the new electronic compensator, it is necessary to correct the zero position, compensate precision and index error of compensator.

Ⅱ. Zero correction of electronic compensator

During changing compensator for instruments or after long term using, zero position or compensate precision of electronic compensator are possible to occur such problems as out of tolerance so that correction shall be done for electronic compensator.

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1

2

3

4

(Figure 3-25) 1. Foot screw I, 2. Foot screw II, 3. Foot screw III

Judgment whether zero position or compensate precision of electronic compensator is out of tolerance:

The instruments shall be placed on the special calibration stand (the settling direction of triangular base shall be shown as Figure 3-25 that elongated bubble is toward operator and foot screw III is facing to collimator tube) for precise leveling so that error in the four directions of plate level shall be no more than 1/2.

Starting-up and zero-crossing is to confirm the compensator is in an open position when the opening mark “CRN” shall be shown in the forth row (see Figure 3-26). If not, the compensator is not opened. Open it. Steps for starting the electronic compensator

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After starting-up, it is understood that the compensator is in the closure if the opening mark “CRN” is not shown in the forth row. It is available for starting-up the compensator as following steps:

1. press (SFT) button (see Figure 3-26), and press (L/R) button to show as Figure 3-27.

(Figure 3-26)

2. Press (L/R) button to show as Figure 3-28. 3. Press (SFT) button to show as Figure 3-26 to start-up the

electronic compensator. Note: the start-up and shutdown of compensator must be performed when the precision of instruments is 2″. If the precision is 5″, 10″ or 20″, the compensator shall be in the closure. Following steps shall be taken for starting-up compensator. Instrument precision shall be introduced in the following zero correction of compensator.

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07–06–07 9:16

1. OFF

07–06–07 9:16

1. ON

(Figure 3-27) (Figure 3-28) Zero correction of compensator:

After precise leveling instrument, carry out the starting-up and zero-crossing. If the vertical angle value is not shown in the column of vertical angle value in the second row in addition to “TILT” (see Figure 3-29), the zero position of electronic compensator is out of tolerance so that it is necessary to correct the zero error of compensator.

06–03–20 14：38

VA T I L T

HA

右 180°10′30″

(Figure 3-29)

1. Shutdown, and press ( ) and (OSET) buttons simultaneously, then press ( ) button for starting-up. After

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showing “FAC” for 1 second on the display screen, the interface shown as Figure 3-30 is shown. The 2″ in the third row means that the precision of instrument leveling angle is 2″.

2. Press ( ) button to show as Figure 3-31. Since settled as 2″ for the instrument at factory, if there is found that it is changed as 5″, 10″ or 20″ due to incorrect operation during maintenance, it is available to press (OSET) button to set it as 2″ again, then press ( ) button for confirmation and storage shown as Figure 3-31.

07–06–07 9:16

S E T A C C

2″

07–06–07 9:16

VA SET 0

(Figure 3-30) (Figure 3-31) 3. zero-crossing of revolving telescope shows the interface as

Figure 3-32 after showing “STEP1” for 1 second. The –110 in the third row in Figure is the zero error of compensator. Under the precondition of precise leveling of plate level, revolving the alidade to any position and after stably stopping the compensator (–110 in Figure 3-32 dose not change any more), the value shall be less than ± 15. Otherwise, the zero position of compensator shall be corrected.

4. The battery case shall be taken down after shutdown. Dismantling 6 M2.5-screws fixing right cover of the instrument is for taking down the right cover. After fixing the battery case, two M3-screws 2 fixing the electronic compensator shall be loosed

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slightly (see Figure 3-34). 07–06–07 9:16

VA 125°10′30″

–110

07–06–07 9:16

VA 125°10′30″

10


4. Error in the four directions of precise leveling instrument and plate level shall be less than 1/2. Repeating above operations from 1 to 2, the display screen is shown as Figure 3-32.

A

B

1

2

(Figure 3-34) 1. Compensator, 2. M3-screw

8. Striking cover of compensator by screwdriver with wooden handle (see Figure 3-34) is to correct the zero error of compensator to being less than ±15. when directing position of telescope, if the

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zero error of compensator is negative (–110 shown as Figure 3-32), strike downwards the A position of the compensator 1 as Figure 3-34. And if it is positive, strike downwards the B position of the compensator 1 as Figure 3-34. So under the precondition of precise leveling of instrument, revolving alidade to any position, absolute value of zero error of compensator shall be less than 15 (as shown in Figure 3-33). If it is a newly changed compensator, the zero position of it may be large due to incorrect mounting position. At this time, two M3-screws shall be loosed for adjusting the compensator so as to perform above correction by slightly fastening two M3-screws after correcting absolute value of zero error of compensator to being less than 100.

9. After fastening two M3 (2) screws fixing electronic compensator, it is available to re-check the zero error of compensator whose absolute value shall be still less than 15. Two M3-screws shall be sealed by varnish.

Precision of compensator shall be corrected after zero correction of compensator.

III. Precision Calibration for Electronic Compensator 1. Conduct precise leveling for the instrument so that the

deviation of all the four directions of the plate level should be less than 1/2 grid.

2. Repeat the above Step 1 and Step 2 in the “zero correction for compensator”. As shown in Figure 3-33, the “10” on the third line is the zero-error of the compensator. The absolute value of the

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zero-error of the compensator should be less than 15 no matter what locations the alidade of the instrument is rotated to (as shown in Figure 3-35).

3. Move the center of reticule of the telescope to aim at the point “A” on the reticule of the collimator tube, press the key 【OSET】 for confirmation after the compensator stop stably (namely the “8” on the third line in Figure 3-35 does not change any more), and then come into the precision calibration mode for the compensator. About one second later when the display shows “STEP2”, the display is shown as in Figure 3-35 (the vertical angle “90°11′32″”in Figure 3-35 is an indicative value).

07–06–07 9:16

VA 90°11′32″

8

07–06–07 9:16

VA 90°08′32″

461


4. Rotate the vertical handwheel slightly so that the collimation axis of the telescope uptilt by 3′. At this time, the value of the vertical angle is changed from 90 ° 11'32 "to 90 ° 08'32".

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07–06–07 9:16

VA 90°14′32″

-449

07–06–07 9:16

VA 90°14′32″

HAR 168°25′01″ TILT


5. Adjust the pedestal foot screw Ⅲ (see Figure 3-25), still Move the center of reticule of the telescope to aim at the point “A” on the reticule of the collimator tube, and press the key 【OSET】 for confirmation after the compensator stop stably. About one second later when the display shows “STEP3”, the display is shown as in Figure 3-36.

6. Rotate the vertical tangent screw slightly so that the collimation axis of the telescope down-tilt by 6′. At this time, the value of the vertical angle is changed from 90 ° 08'32 "to 90 ° 14'32".

7. Adjust the pedestal foot screw Ⅲ (see Figure 3-25), still Move the center of reticule of the telescope to aim at the point “A” on the reticule of the collimator tube (as shown in Figure 3-37), press the key 【OSET】 for confirmation after the compensator stop stably, and the precision calibration for the compensator is completed. About one second later when the display shows “SET”, the display is shown as in Figure 3-38.

After calibration is completed, the test on the compensation precision of the compensator should be carried out.

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IV. Test on the Compensation Precision of Compensator

1. Place the compensator on the calibration stand, with the direction of the triangular pedestal put as shown in Figure 3-25, with elongated bubble pointing toward the operator, and with the foot screw Ⅲ opposite the collimator tube. Conduct precise leveling so that the deviation of all the four directions of the plate level should be less than 1/2 grid. Start the compensator, wait for zero passage, and confirm the compensator is turned on.

2. Move the telescope to aim at the point “A” on the reticule of the collimator tube, and read the value of the vertical angle after it is stable.

3. Clockwise rotate the pedestal foot screw Ⅲ to back-tilt the compensator by 3′(If the value of the grids on the collimator tube is 18″, up to 10 grids can be tilted). Rotate the vertical handwheel slightly to let the telescope aim at the point “A” on the reticule of the collimator tube again. Read the value of the vertical angel, the error should be less than 6″.

4. Anticlockwise rotate the pedestal foot screw Ⅲ to front-tilt the compensator by 3′. Rotate the vertical handwheel slightly to let the telescope aim at the point “A” on the reticule of the collimator tube again. Read the value of the vertical angel, the error should be less than 6″too.

3.5 Setting of Index Error, Collimation Error, and Zero

Error for Compensator When you use positive and inverted telescope to measure the

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vertical angle of the same object “A”, if the total of the two reading values measured is not equal to 360° , then the half of the difference between the total and 360° is the zero error of the vertical angle. For the 2″class compensator, if the zero error is more than 10″, the calibration is necessary (Note: please confirm the compensator is turned on before calibration).

If the index error is very bad, you can conduct setting as follows. Measure the angles of the left limb and the right limb, and set the index of the vertical limb again to let the index error meet technical requirements. At the same time, measure the collimation error of the compensator so that the compensator can correct the collimation error for the measured value (Due to the correction range of the collimation error is less than 30″, if 2C＞30″, you must correct and keep the error of the vertical axis of the collimation axis within 30″). Besides, the zero error of the tilt sensor also can be measured and set.

Note: After the modes of “the display unit of the smallest reading value” and “tilt compensation function” are changed, above calibrations should be carried out once more.

Setting method is as follows: 1. Place the compensator on the calibration stand and conduct

precise leveling so that the deviation of all the four directions of the plate level should be less than 1/2 grid.

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07–06–07 9:16

VA SET 0

07–06–07 9:16

SET F1

HAR 8°25′01″


2. Press the key 【L / R】and the key 【】to start the compensator. One second later when the display screen shows “SETUP”, the prompt interface of zero passage is displayed, as shown in Figure 3-39. Rotate the telescope to pass zero, the prompt “SET F1 is displayed on the second line of the display screen” in a flashing manner, as shown in Figure 3-40.

3. For the positive telescope (on the left of the limb), move the telescope to aim at the point “A”, press the key【OSET】for confirmation. After the “SET F1” on the second line flashes several times, the prompt of “SET F2” is displayed, as shown in Figure 3-41.

07–06–07 9:16

SET F2

HAR 8°25′01″

07–06–07 9:16

SET

HAR 168°34′59″


4. For the inverted telescope (on the right of the limb), rotate 78

the alidade by 180°, and still move the telescope to aim at the point “A”, and press the key【OSET】for confirmation. After the “SET F2” on the second line flashes several times, the prompt of “SET” is displayed, as shown in Figure 3-41.

5. Press the key 【 OSET 】 for confirmation, and the compensator accepts the newly set index error, collimation error, and zero error, and goes back to the mode of angel measurement.

After these settings are completed, check the changes of index error and 2C of the vertical limb, and both should meet technical requirements.

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Chapter IV Examination and Correction of

Geometric Relationship

Conduct the examination and correction of geometric relationship according to the following order. This is because that the relationship and interacting between various verification items should be considered. For example, for such item will affect the subsequent verification of various items, it is ought to firstly verify the perpendicularity between plate level axis and vertical axis.

4.1 Check whether the plate level axis is perpendicular

to vertical axis as well as make correction

I. Examination

Place the instrument on the stationary instrument pedestal or foot stand. After placing the instrument well, rotate the alidade and read the maximum value at the both sides of bubble as the verification result, of which the deviation should not exceed the half value of division for plate level, if exceeded the deviation, make correction.

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1

2

3

4

(Figure 4-1)

1. Foot screw I 2. Foot screw II 3. Plate level 4.Foot screw III

II 、Correction

1. Rotate alidade to so as to the axes of plate level3 is parallel to the connecting line between foot screw I and foot screw II (see Figure 4-1).

2. Rotate pedestal foot screw II or foot screwier of base to center the bubble of plate level 3.

3. rotate alidade for 180°(or 200g), if the bubble deviates center and exceeds the deviation, adjust the foot screw I shown in Figure4-1 to move the bubble towards center by the half deviation.

4. Rotate the adjustment screw 1 shown in Figure 4-2 with alignment to move the bubble 2 towards center until to be in center.

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21

(Figure 4-2)

1. Adjustment screw 2. Plate level

5. Rotate the alidade for 180°(or 200g), read the maximum value at the both sides of bubble, of which the deviation does not exceed the half value of division for plate level and such one can be considered to be qualified, if exceeded the deviation, repeat the above correction steps.

4.2 check whether the circular level axis is parallel to

vertical axis as well as make correction

I、 Examination

After the instrument being placed well, the bubble of circular level should be in center and not exceed the division circle of circular level. If exceeded, make correction.

II、 Correction

Conduct the correction of circular level after the correction of plate level, which is fast and fine.

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1

(Figure 4-3)

1. Adjustment screw

Adjust the three adjustment screws 1 until the bubble of circular level is in the center of division circle of circular level. During the adjustment, please take care that the adjustment for the screws in relative position should take the principle of one loosely first and one tightly second, wherein, only loosely but not tightly can twist off adjustment screw.

After the bubble being corrected into correct position, the three adjustment screw should be in the place where the degree of tightness is suitable. If too loose, the position of leveling instrument will change after the vibration. If too tight, due to the change of internal stress, the position of leveling instrument may change after a long time. Sometimes, it can damage the optical element in corrected areas, such as glass broken and glue phenomenon. This will also be applied in the other corrected areas described

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afterwards (such as correction screw with cross wire, correction screw of optical plummet).

4.3 Inspection and Correction for Whether Horizontal

Wire of Cross Wire is Perpendicular to Vertical Axis

I. Examination

It always uses the vertical wire of the cross wire in the field measurement. Therefore, in the inspection and correction, it often only checks whether the vertical wire is plumb or not. There are two methods in the field measurement:

First method: Carefully level the instrument, aim at a clear target point beyond 50m with the top or bottom of the vertical wire of the telescope, then after fixing the alidade, tighten the brake handwheel on the horizontal axis. Slightly move the vertical handwheel, observe the movement of the target point in the field of vision, at the same time make the telescope turn in the vertical plane, if the target point still does not deviate from the vertical wire after it moves from one end of the vertical wire to the other end, it is proved that the vertical wire is plumb. If there has obvious deviation, it is necessary to correct.

Second method: Carefully level the instrument, stand 20~30m away from the instrument, then hang a plumb bob with a thread with a diameter of 0.5~1.0mm. After the plumb bob is stable, compare the vertical wire and the plumb bob thread, if both of them coincide, it is proved that the vertical wire is plumb. If there has obvious deviation, it is necessary to correct.

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II. Correction

To carry out the inspection according to the above methods, if there has obvious deviation, it can correct in light of the following steps:

1. Screw off the protecting cover 1(sees Figure 4-4). 2. Loose the four bolts 3 fastening the ocular head set 2 (see

Figure 4-4). 3. Rotate the ocular head set 2 to remove the deviation, and

tighten the four bolts 3. After inspected and accepted according to the above-mentioned methods, install the protecting cover 1.

III. Cautions

When use the first method to inspect, if the target moves along a curved line or it accompanies with jumping in the movement, at the moment of slightly moving the vertical handwheel, it is mostly caused by the uneven loads on the fine-motion screw, it should be excluded previously. It also can refer to the above methods, slightly move the horizontal handwheel to check wether the horizontal wire is horizontal or not. Because the vertical wire will be plumb likewise after leveling the horizontal wire (in the processing, it has ensured the verticality between the horizontal wire and the vertical wire on the stadia plate, the error of nonperpendicularity can not more than 5´).

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1

2

3

(Figure 4-4) 1. Protecting cover 2. ocular head set 3. bolt

4.4 Examination and Correction for Whether

Collimation Axis is Perpendicular to Horizontal Axis of

Telescope

I. Examination

It usually uses the staff method to inspect and correct. As shown in Figure 4-5, Staff A and B are horizontally placed in the two places which are approximately on the equal height with the instrument, and the distances to the instrument are equal (mainly to avoid the impact of error of focusing). After level the instrument, aim at a division line N on the A staff by the direct telescope. Then tighten the alidade (i.e. tighten the horizontal brake handwheel),

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reverse the telescope to collimate B staff, a reading M1 will be gained from B staff (1.650m as shown in Figure 4-4). Then loose the horizontal brake handwheel, turn the alidade to make the telescope aim at N on A staff for the second time. Then tighten the alidade, and reverse the telescope, if the cross wire of the telescope still aims at M1 on B staff, it is illustrated the two axis is perpendicular to each other. If the cross wire deviates to M2 (1.630m as shown on Figure 4-4), it is presented that there is a collimation error. Calculated according to the following formula:

1/4 M1 M2C″= S

•ρ″≥ allowable value

This series of electronic theodolite belongs to Class 2" instrument. When the allowable value is not less than 8", it is needed to correct.

N

S

A B

M (1.630)M (1.635)

M (1.650)

2

1仪器

Instrument

(Figure 4-5)

II. Correction

When making the correction, take down the protecting cover 1

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in Figure 4-6, switch the two regulating screw 2 on the left side and the right side to make the vertical wire moves horizontally from M2 (sees Figure 4-5), and to reduce 1/4 of the offset M1M2, that is from 1.630m in the Figure to 1.635m, at this moment, the collimation axis is perpendicular to the horizontal axis. Repeat the above-mentioned operation, and after inspected and accepted, install the protecting cover 1.

12

(Figure 4-6) 1. Protecting cover 2. regulating screw

4.5 Examination and Correction for Coincide Between Collimation Axis of Optical Plummet and Central Line of Vertical Axis

I. Examination

Place the instrument on the tripod leg, and approximately level it (not sure to strictly level). Adjust the ocular cap as shown in

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Figure 4-7 to see the division spanner clearly. Then turn the focusing handwheel 3 to see the target A on the ground clearly. Move the instrument or the target to make the aimed target A (sees Figure 4-8) on the center of the division spanner. Then turn the alidade 180° (or 200g), if the target deviates from the center (for example deviates to B as shown in Figure 4-8), it is presented the collimation axis of the optical plummet is not coincident to the central line of the vertical axis. In the height of 0.8~1.5m, the offset shall be less than 1mm. If it exceeds the offset, it is needed to correct.

43 2

1

(Figure 4-7) 1. Protecting cap 2. ocular cap 3. focusing handwheel 4. correction screw

II. Correction

1. Screw off the protecting cap 1 of the optical plummet in Figure 4-7.

2. Trough regulating the correction screw 4, adjust the half offset of the target, that is correct the target on B in Figure 4-8 to C.

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3. Adjust the pedestal foot screw to make the centre of the division spanner aim at the target on the ground (refers to Figure 4-8).

B

A

C

(Figure 4-8)

4. Turn the alidade 180° (or 200g), if the target still deviates from the center and exceeds the offset, it is necessary to repeat the above-mentioned correction steps, until turn the alidade to any place to observe, the target is on the center of the division spanner.

5. Install the protecting cap 1 of the optical plummet.

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Appendix I: Error Information

Error prompt

Error description

E01 Index error of vertical limb is set incorrectly or exceeds the offset

E02 Zero point of the compensator is set incorrectly or exceeds the offset (the bubble is not pounded out)

E03

Collimation error is set incorrectly or exceeds the offset(the axile line offset produced by the collimation axis is perpendicular to the horizontal axis)

E04 Writing memory is incorrect

E05 Precision setting of compensator is incorrect

E06 Angle measuring system is incorrect

E07 Instrument’s alidade or the telescope rotates excessively rapid (exceeding 4s/r)

E08 Angle measurement of the horizontal plate is incorrect

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DT-5A theodolite Repair manual.pdf

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