Metal Electrode Meter

INSTRUCTION MANUAL

FOR

Metal Electrode Meter

MODEL 2900

Serial #__________

Date____________

A-M Systems, Inc.PO Box 850

Carlsborg, WA 98324U.S.A.

360-683-8300 ♦ 800-426-1306FAX: 360-683-3525

http://www.a-msystems.com

Version 3.0April 2004

Each Metal Electrode Meteris delivered complete with:

Power SupplyRack Mount Hardware

Instruction ManualInput Cable

Adjustment tool

NOTE

This instrument is not intended for clinical measurements using humansubjects. A-M Systems, Inc. does not assume responsibility for injury or

damage due to the misuse of this instrument.

ContentsGeneral Description ............................................................................................................................ 1Instrument Features ............................................................................................................................................. 1Controls and Connectors ..................................................................................................................................... 2Operating Instructions ....................................................................................................................... 3Typical Set-Up Procedure .................................................................................................................................... 3Safety considerations ........................................................................................................................................... 6Problem Solving .................................................................................................................................................. 6Calibration Procedures ...................................................................................................................... 6Specifications....................................................................................................................................... 7Warranty and Service ........................................................................................................................ 9

1A-M Systems, Inc. 131 Business Park Loop, P.O. Box 850 Carlsborg, WA 98324Telephone: 800-426-1306 * 360-683-8300 * FAX: 360-683-3525E-mail: [email protected] * Website: http://www.a-msystems.com

General Description

Instrument FeaturesThe Model 2900 Metal Electrode Meter is designed to quickly measure the impedance of metalmicroelectrodes. Impedance is an important predictor of the electrode’s recording and stimulatingproperties.

The Model 2900 Metal Electrode Meter uses an oscillating small current source to measure theelectrical properties of metal electrodes. A default 1kHz, 100nA signal is applied to the electrode. Amicroprocessor-controlled measurement is made and the resulting value of impedance is displayed ona digital meter for easy reading. The frequency and/or current of the test oscillating signal can beadjusted by the front panel controls if desired by the user.

The Model 2900 Metal Electrode Meter can measure electrode impedances from 1 kOhms to 20MegOhms.


Controls and Connectors

DISPLAY / MODE:Various messages, as well as the actual electrodeimpedance, will be legible on the DISPLAY.This pushbutton switch controls the MODE theunit is operating in. Upon powering on, the unitwill enter the AUTOmatic mode, as indicated bythe word AUTO in the display. Depressing the button once will switch the unit unto manual mode,where the user can set the test signal FREQUENCY, CURRENT, and the unit’s GAIN sensitivity byrotating the CONTROL knob. Care needs to be used in modifying this setting to ensure maximal gainwithout signal saturation.

CONTROL:This knob adjusts the value of the test signal’s frequency or current, or the meter’s gain,depending on the setting of MODE.

CALIBRATE:The test signal can be monitored at this BNC connector. If the signal isexhibiting high frequency oscillations, then the small adjustment screw shouldbe turned until the oscillations are eliminated.

INPUT & GND:The Model 2900 comes with a dual banana to dual micro-clip cable. The banana plugwith the ground tag should be connected to the GND input connector, and the blackmicro-clip should be connected to a reference wire. The red micro-clip, which shouldbe connected to the electrode, will be connected to the red INPUT connector.

POWER This switch turns the Metal Electrode R/C Meter ON or OFF.

Rear Panel POWER INPUTThis jack connects the DC power source to R/C Electrode Meter. The DC supplyprovides +15V, -15V, and +5V.


Operating Instructions

AUTOmatic ModeThis is a generalized procedure for setting up the Model 2900 Metal Electrode Meter for measuringelectrode characteristics. Portions of this procedure may need to be modified for your specificapplication.

1. Fill a beaker with physiological saline (or the solution in which the tissue will be bathed). Thesolution should have the same temperature and ionic strength as that in which your experimentswill be made.

2. Connect the supplied dual banana to micro-clip cable to the INPUT and GND connector on thefront panel. Make sure the ground tab on the dual banana plug is plugged into the black GNDconnector on the front panel. If you use a different cable than the one supplied with the Model2900 than you may have to re-calibrate the instrument (See cable calibration).

3. Attach a reference wire (generally an Ag/AgCl reference electrode) to the black micro clip, andplace the end into the saline within the beaker.

4. Dip the electrode to be measured and the reference electrode into the beaker of physiologicalsaline solution Note: immerse the metal microelectrode to approximately the same depth aswill be used during the experiment.

5. Turn the POWER switch to ON and allow the Model 2900 to warm up for 1 minute.

6. Connect the red micro-clip to the electrode to be measured.

7. The unit will begin to measure the impedance of the electrode. When complete, the display willsettle on the final value.

8. If the value of impedance is below 1kΩ, the meter will display 0kΩ. If the impedance is over20MegΩ, the meter will display OVERRANGE.

10. MODE

This pushbutton switch controls the MODE the unit is operating in. Upon powering on, the unit willenter the AUTOmatic mode, as indicated by the word AUTO in the display. In AUTO mode, the unitwill automatically search for the optimal gain required to read the electrode’s impedance. Depressingthe button once will switch the unit unto manual mode, where the first setting that can be adjusted isFREQUENCY. Rotating the CONTROL knob will modify the test signal’s frequency. Depressing thebutton again will display the next setting that can be adjusted: CURRENT. Rotating the CONTROLknob will modify the test signal’s current setting. Depressing the button again will display the nextsetting that can be adjusted: GAIN.


Operating Instructions

Manual ModeThis is a generalized procedure for setting up the Model 2900 Metal Electrode Meter for measuringelectrode characteristics. Portions of this procedure may need to be modified for your specific application.

1. Fill a beaker with physiological saline (or the solution in which the tissue will be bathed). The solutionshould have the same temperature and ionic strength as that in which your experiments will be made.

2. Connect the supplied dual banana to micro-clip cable to the INPUT and GND connector on the frontpanel. Make sure the ground tab on the dual banana plug is plugged into the black GND connector onthe front panel. If you use a different cable than the one supplied with the Model 2900 than you mayhave to re-calibrate the instrument (See cable calibration).

3. Attach a reference wire (generally an Ag/AgCl reference electrode) to the black micro clip, and placethe end into the saline within the beaker.

4. Dip the electrode to be measured and the reference electrode into the beaker of physiological salinesolution Note: immerse the metal microelectrode to approximately the same depth as will beused during the experiment.

5. Turn the POWER switch to ON and allow the Model 2900 to warm up for 1 minute.

6. Connect the red micro-clip to the electrode to be measured.

7. Depress MODE once. The meter will enter the manual mode, and display the instruction SETFREQUENCY.

8. Rotating the CONTROL knob will cycle through the available signal frequencies:

200Hz, 400Hz, 500Hz, 800Hz, 1.0kHz, 2.0kHz, 5.0kHz, and 10kHz.

Pressing MODE again will enter the selected frequency, and then the unt will display the instructionSET CURRENT.

9. Rotating the CONTROL knob will cycle through the available test signal current levels:

10nA, 20nA, 50nA, 100nA,

Pressing MODE again will enter the selected current level, and then the unt will display the GAINdisplay.

10. In this display, the bar graph indicates the sensitivity of the unit. The CONTROL knob should berotated until the bar graph extends to within 5 lines (one block) of the vertical tick mark in the upperline. If the bar graph extends significantly beyond the tick mark, then the test signal is not within thetolerance of the internal A/D, and the measurement is not accurate. Similarly, if the bar is significantlyless than the tick mark, than the sensitivity of the unit is too low, and the measurement is inaccurate.


11. Depress MODE once more. The meter will return to the AUTO mode, but the current andfrequency used will be those values set by the user.

One way to return to AUTO mode with the unit’s defaults of 1.0kHz and 100nA test signal, thepower can be turned off and on.


Safety considerationsRemoval of the cover will expose the electronic components. Capacitors inside the instrumentmay still be electrically charged even when the instrument has been disconnected from allpower sources.

Problem SolvingIf the Model 2900 does not function properly, consult the following list of suggested solutions to the mostcommon problems. If you need further assistance, please contact technical support at A-M Systems, Inc.

Problem Cause / Solution

Values keep changing There is most likely too much noise in your setup.Try turning off unnecessary equipment. Shieldthe metal microelectrode, reference electrode, inputcables and the Model 2900 from external noise.

Increase the signal size by entering manual mode andchanging Frequency, Current, and or Sensitivity.

The meter always reads The unit is most likely out of calibration or you have aover-range broken connection to your electrode. Try re-calibrating

the unit.

Cable calibrationControls Inputs / Observations Adjust / Check

Power: On Connect an input cable and a resistorDisplay: AUTO of similar value of the electrodes

to be measured across the inputs.Connect a BNC cable to the BNC connectorand to an oscilloscope.

Observe Oscilloscope. Adjust CAL screw until waveformbegins to oscillate. Then back off(turn CAL screw counter-clockwise) one quarter turn.


Specifications

InputImpedance 1013 Ω || 1pF

Internal signal sourceFrequency (AUTO default = bold) 200Hz, 400Hz, 500Hz, 800Hz, 1.0kHz,

2.0kHz, 5.0kHz, and 10kHz. Sine wave

Amplitude 10nA, 20nA, 50nA, 100nA,

Meter OutputImpedance 1 kΩ - 20 MΩ ; 2 significant digits

Power+15 Vdc 50 mA- 15 Vdc 50 mA+ 5 Vdc 100 mA

DC voltages are used in the METER, so it can be used inside a Faraday cage

Physical DimensionsWidth 8.45 inches (21.46cm)Height 2.55 inches (6.477 cm)Depth 3.95 inches (10 cm)Weight 12 lbs.


Model 8750 Remote power supplyInput: 100-240 VACEING 50/60 Hz, 1.0 A MAX.Output +15 Vdc 2.0 A

-15 Vdc 0.5 A+5 Vdc 3.0 A36 W Max


Warranty and Service

What does this warranty cover?A-M Systems, Inc. warrants to the Purchaser that the Instrument, excluding cables, Headstage Probes and anyother accessories shipped with the Instrument, (hereafter the “hardware”) is free from defects in workmanship ormaterial under normal use and service for the period of one (1) year. This warranty commences on the date ofdelivery of the hardware to the Purchaser.

What are the obligations of A-M Systems, Inc. under this warranty?During the warranty period, A-M Systems, Inc. agrees to repair or replace, at its sole option, without charge to thePurchaser, any defective component part of the hardware. To obtain warranty service, the Purchaser must return thehardware to A-M Systems, Inc. or an authorized A-M Systems, Inc. distributor in an adequate shipping container.Any postage, shipping and insurance charges incurred in shipping the hardware to A-M Systems, Inc. must beprepaid by the Purchaser and all risk for the hardware shall remain with purchaser until such time as A-M Systems,Inc. takes receipt of the hardware. Upon receipt, A-M Systems, Inc. will promptly repair or replace the defectiveunit, and then return the hardware to the Purchaser, postage, shipping, and insurance prepaid. A-M Systems, Inc.may use reconditioned or like new parts or units at its sole option, when repairing any hardware. Repaired productsshall carry the same amount of outstanding warranty as from original purchase, or ninety (90) days which ever isgreater. Any claim under the warranty must include a dated proof of purchase of the hardware covered by thiswarranty. In any event, A-M Systems, Inc. liability for defective hardware is limited to repairing or replacing thehardware.

What is not covered by this warranty?This warranty is contingent upon proper use and maintenance of the hardware by the Purchaser and does not coverbatteries. Neglect, misuse whether intentional or otherwise, tampering with or altering the hardware, damage causedby accident, damage caused by unusual physical, electrical, chemical, or electromechanical stress, damage causedby failure of electrical power, or damage caused during transportation are not covered by this warranty. Productsmay not be returned to A-M Systems, Inc. for service, whether under warranty or otherwise, which arecontaminated by infectious agents, radioactive compounds or other materials constituting a health hazard toemployees of A-M Systems, Inc.

What are the limits of liability for A-M Systems, Inc. under this warranty?A-M Systems, Inc. shall not be liable for loss of data, profits or savings, or any special, incidental, consequential,indirect or other similar damages arising from breach of contract, negligence, or other legal action even if thecompany or its agent has been advised of the possibility of such damages, or for any claim brought against you byanother party. THIS EQUIPMENT IS NOT INTENDED FOR CLINICAL MEASUREMENTS USING HUMANSUBJECTS. A-M SYSTEMS, INC. DOES NOT ASSUME RESPONSIBILITY FOR INJURY OR DAMAGE DUETO MISUSE OF THIS EQUIPMENT. Jurisdictions vary with regard to the enforceability of provisions excluding orlimiting liability for incidental or consequential damages. Check the provision of your local jurisdiction to find outwhether the above exclusion applies to you.This warranty allocates risks of product failure between the Purchaser and A-M Systems, Inc. A-M Systems, Inc.hardware pricing reflects this allocation of risk and the limitations of liability contained in this warranty. Thewarranty set forth above is in lieu of all other express warranties, whether oral or written. The agents, employees,distributors, and dealers of A-M Systems, Inc. are not authorized to make modifications to this warranty, oradditional warranties binding on the company. Accordingly, additional statements such as dealer advertising orpresentations, whether oral or written, do not constitute warranties by A-M Systems, Inc. and should not be reliedupon. This warranty gives you specific legal rights. You may also have other rights which vary from onejurisdiction to another.

Metal Electrode Meter - A-M Systems

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