ESSEX ENGINEERING CORPORATION

2000 SERIES CONTROL SYSTEMS:2000 series are for surface mounting inside a control cabinet

Model 2024 Electronic AlternatorDuplex (two pump) pump control

2400 SERIES CONTROL SYSTEMS:2400 series units are for front panel (semi-flush) mounting

Model 2402 Pump Status ModuleStatus indication and control of pumps

Model 2403 Valve Status ModuleStatus indication and control of 2-position valves

Model 2404 AnnunciatorProvides up to 4 points of alarm annunciation

Model 2406 Sequencer Manual sequence selection of process control contacts

Model 2407 Alternator ModuleDuplex, triplex or quadraplex pump control alternator

Model 2410 Pump ControllerConverts current signal to 4 on-off contact closures plus high, low and signal loss alarms

Model 2411 Duplex Pump ControllerConverts current signal to 2 on-off contact closures plus high, low and signal loss alarms and alternation

Model 2415 Manual Loading StationAuto/Manual loading station with digital indication of analog signal

Model 2416 Manual Loading StationAuto/Manual loading station with digital indication of analog signal and output

Model 2420 Ratio Station ModuleProvides ease of use and flexibility in chemical feed systems

3000 SERIES EQUIPMENT:Includes power supplies, loop power supplies, lightning arrestors, remote relays, etc.

Model 3800 Line Protection UnitSurge protection for 4-20mADC signal lines

Model 3804 Relay Interface Module(4) SPDT 24 VDC relays and terminal blocks mounted on a compactbase for track mounting

Model 3805 Relay Interface Module(2) DPDT 24 VDC relays and terminal blocks mounted on a compactbase for track mounting

Model 3824 Relay Interface Module(2) SPDT 24 VDC relays and terminal blocks mounted on a compactbase for track mounting

Model 3905 Duplex AlternatorA reliable, modular unit designed specifically for use with the Model 2410 Controller to provide alternation

Model 3907 Loop Power SupplyA reliable, modular unit designed specifically for providing looppower for instrument systems

WATER/WASTEWATER TREATMENTCONTROL SYSTEMS AND SUBSYSTEMS

ESSEXENGINEERING CORPORATION

REPRESENTED BY

COMPLETE CONTROL SYSTEMSESSEX ENGINEERING CORPORATION designs and builds complete controlsystems for water and wastewater treatment and other industries. We would bepleased to quote on any requirements you may have of this nature. Registeredprofessional engineering assistance is available if needed.

©2008 Essex Engineering Corp. All Rights Reserved. Printed in U.S.A. Pub. No. INDEX-7000, Rev. 1

ESSEX ENGINEERING CORPORATION21 Industrial Drive • Ivyland, PA 18974 • 215-322-5880 • FAX 215-322-8368 • www.essexeng.com

. . . . Provides a reliable, flexible system of starting, stopping, sequencing of pumps, blowers, & other devices.

FEATURES� Modular Construction . . . Control/Display

Circuit board is easily replaced

� Alarm Silence circuitry for Audible Alarms

� All functions provided with momentary test switches

� Built in time delay prevents simultaneous lead/lag unit operation on power-up

� Lead/lag unit preference easily switch selected

� Level signals are indicated by L.E.D. lamps

DESCRIPTION

The Essex Engineering Model 2024 ElectronicAlternator is a versatile, reliable system for use instarting, stopping and sequencing pumps, blowers,or other equipment to be cycled. For instance, as thelevel in a basin or other container changes, the levelsensing switches monitor these changes andtransmit a signal to the electronic alternator. Thealternator, upon receiving the proper signal, willeither start or stop the pumps in proper sequence.

There are separate turn-on and turn-off points for control,and for high level alarm. Isolated output contacts areprovided for pump operation and alarms. The standardunit will operate from a 4 or 5 level point system, and haslock-in or non-lock-in sequence for lag level which can befield modified.

High level alarm point can be field set for lock-in,manual reset, or automatic reset. Relay K4 canfollow K3 for DPDT switch operation, or be used asan audible device relay, dropping out when AlarmSilence pushbutton is added.

The electronic alternator also has a six second timedelay to prevent the lag pump from startingsimultaneously with the lead pump after a powerfailure, thus protecting an emergency generator fromhigh inrush starting current requirements.

MODEL 2024ELECTRONIC ALTERNATOR


©2004 Essex Engineering Corp. All Rights Reserved. Printed in U.S.A. Pub. No. 2024-7000, Rev. 2


REPRESENTED BY

MODEL 2024 SPECIFICATIONS

AMBIENT OPERATING TEMPERATURE RANGE0 to 40 oC

POWER INPUT120 VAC + 10% 10W Max.12 VDC + 10% 450 mADC

CONTACT INPUTS12 VDC @ 10 mA Max.

CONTACT OUTPUTS10A resistive @ 240 VAC

TIME DELAYSApproximately 6 seconds

ELECTRICAL CONNECTIONS - OVERALL DIMENSIONS

. . . . Provides status indication and control of pumps, blowers and other types of motors.

FEATURES� Bright, long life LED'S give reliable indication of

status and monitoring of control functions.

� HAND-OFF-AUTOMATIC selector switchesprovide automatic and manual override capability.

� Provides visual indication of actual motor start or stop.

� 120VAC/24VD/12VDC power source.

� Auxiliary output contacts on all front panel switches provide remote monitoring or special "system" interlocks.

DESCRIPTION

The Essex 2402 Pump Status Module operates inthe following manner:

Assuming the pump is in the off condition, the greenOFF indicator is l i t . I f the HAND-OFF-AUTOpushbuttons are indexed to AUTO, and an externalcontact closure occurs which enables the pump ormotor to start, an amber CALL indicator will light.Once the pump starts, an auxiliary contact on themotor starter, pressure switch, flow switch, etc.sends a "report back" signal to the 2402 causing thered RUN light to come on and the green OFFindicator and amber CALL indicator to go out.

If the pump fails to start, or fails to stop within a 0.2to 60 second field adjustable time, the red FAIL lampwill flash, indicating trouble and an optional externalhorn will sound. Depressing the ALM/ SIL button willsilence the horn and cause the FAIL indicator to lightsteadily.

If the HAND-OFF-AUTO pushbuttons are indexed toHAND, an amber CALL indicator will light and theunit will operate as described above.

Auxiliary contacts are included on the HAND-OFF-AUTO pushbuttons to provide remote monitoring ofthese switches, or to provide the capability forexternal interlocking. Field selectable power up orcontrol input timing is standard. This providesstaggered starting of unit after a power failure ordelayed starting each time the unit is activated. Allindicators light for approximately 1 second on powerup or can be checked at any time using ALM/SILbutton.

All of the switches and indicators on the instrumentface are sealed for ease of cleaning and theprevention of switch contamination from grease, dirt,etc.. Units are provided with a custom engravedlabel identifying the use of the Pump Status Module.

MODEL 2402PUMP STATUS MODULE




POWER INPUT120 VAC + 10% 15W max.24 VDC + 10% 650 mADC max.

12 VDC + 10% 1200 mADC max.

CONTROL INPUTSContact closure or NPN transistor; 10 mADC max. @ 24 VDC

CONTROL OUTPUTSNPN solid state output; 50 VDC @ 60 mADC max. per point; 1 output for each pump starter, valve operator, failalarm, and horn

INDICATORSFour front panel LED indicators display status and controlfunctions of unit

SWITCHESSealed contact inputs one each for AUTO, OFF, HAND andALM/SIL

REPRESENTED BY

CUTOUT DIMENSIONS OVERALL DIMENSIONS

ELECTRICAL CONNECTIONS



. . . . Provides status indication and control of two-position valves.

FEATURES� Long life LED's provide indication of status and

monitoring of control functions.

� OPEN-CLOSE-AUTO selector switches provide automatic operation with manual override.

� Failure system provides visual indication if valve fails to respond to control signal.

� Optional audible alarm available.

� 120VAC/24VDC/12VDC power source.

DESCRIPTIONAssuming the valve being controlled has limitswitches which will signal a fully open, or fully closedposition, the 2403 Valve Status Module operates inthe following manner:

If the valve is closed, the green CLOSED indicatorwill be lit. If the OPEN-CLOSE-AUTO pushbuttonsare indexed to the AUTO mode, and an externalcontact closure signals the valve to begin to open,the red OPEN indicator wil l begin to f lashintermittently, indicating the valve is to travel to thisposition.

As the valve begins to open, the green CLOSEDindicating lamp will go out, and the amber TRAVELindicating lamp will glow steady, until the valve isfully open. When the valve is fully open the TRAVELlamp will go out and the red OPEN indicating lampwill glow steady.

When operation is reversed and the valve is to close,the red OPEN indicator goes out, the greenCLOSED indicator flashes, and the amber TRAVELlight glows steady. When the valve reaches a fullyclosed position, the amber TRAVEL light will go outand the green CLOSED light will go from a flashingto a steady state condition.

A time delay valve failure monitoring system isstandard equipment, and is field adjustable from 0.2to 60 seconds. If the valve does not operate withinthe specified time, the red FAIL indicating light willcome on steadily. When coupled with the EssexModel 2401 Alarm Module, the red FAIL indicator onthe 2403 will flash and an audible alarm will soundfrom the 2401. By pushing the alarm button oneither the 2401 or 2403, the alarm will be silenced,and the red FAIL light will glow steady.

An optional failure relay is available to activateexternal devices should a valve fail.

Auxiliary contacts are included on the OPEN-CLOSE-AUTO pushbuttons to provide remotemonitoring of these switches, or to provide thecapability for interlocking. By using the electronicCONTROL output, or the FAIL output, a remote24VDC relay can be used to provide additionalcontacts and higher current ratings where needed.

MODEL 2403VALVE STATUS MODULE





12 VDC + 10% 1200 mADC max.


CONTROL OUTPUTSNPN solid state output; 50 VDC @ 60 mADC max. per point; 1 output for each valve operator, fail alarm, and horn

INDICATORSFour front panel LED indicators display status and controlfunctions of unit

SWITCHESSealed contact inputs one each for AUTO, OPEN, CLOSE andALM/SIL

REPRESENTED BY





. . . . Visually identifies an abnormal device or condition.

FEATURES� All solid state circuitry.

� Optically isolated alarm input contacts.

� 120VAC/24VDC/12VDC power source.

� Long life LED indicating lamps.

� Can accommodate from one to four points per unit.

� Switch selectable lock-in/nonlock-in and N.O./N.C. alarm input controls.

� Optional time delay on input.

ALARM SEQUENCE CHART

FIELD ALARM AUDIBLECONDITION CONTACT LIGHT ALARM*

Normal Normal Off OffAlarm Abnormal Flashing On

Silence Abnormal On OffNormal Normal Off Off

Lamp Test Normal On Off

*Mounted Externally

DESCRIPTION

The Essex Model 2404 Annunciator is designed tomonitor Alarm Contacts and provide "point"indication on the device which is alarming. Thestandard unit comes equipped to monitor two remotepoints, but can be optionally equipped toaccommodate four points.

Each point has a selector switch located on the 2404drawout PC board, which will allow the point to beset up to monitor a normally open, or normallyclosed contact. A lock-in/nonlock-in switch is alsoprovided on the PC board for each point.

On lock-in or nonlock-in, the alarm indication flashesunti l acknowledged, whereupon it wil l l ightcontinuously until the field condition is corrected. Inlock-in status, the alarming point must beacknowledged before it will reset. In the nonlock-instatus, the unit will cease to alarm if the point beingmonitored returns to normal.

An auxiliary output NPN transistor is standard foreach alarm point. Transistor follows activation of thefield input contact.

An optional 0.1 to 60 second time delay is availableon the input circuit. This avoids unnecessary alarmindication for those conditions which may be onlymomentary.

MODEL 2404ANNUNCIATOR





12 VDC + 10% 1200 mADC max.

CURRENT THRU FIELD TROUBLE CONTACT5mADC at 24VDC; optically isolated

OPTIONAL TIME DELAY0.1 to 60 second delay is available as a time delay on inputbefore alarm is activated.

AUXILIARY OUTPUTS Each alarm point has a NPN transistor auxiliary outputcapable of driving relays, lights, etc. Maximum transistorrating:50VDC @ 60mADC.

REPRESENTED BY





. . . . Provides sequencing, cascading and/or paralleling of many pumps.

FEATURES� Front of panel switches provide easy setup of

sequencing.

� Reliable...conservatively designed solid state control circuitry and isolated output circuits assure long operating life. Inputs are optically isolated from the 2406 electronics.

� Field selectable operation for filling or emptying.

� Long life LED's for input and output indication.

� Multiple units may be cascaded and/or paralleledto allow for control of more devices and/or levels.

DESCRIPTION

The Essex Engineering Model 2406 is a simple, yetreliable unit designed to offer the maximum ofversatility in sequencing the operation of pumps orother operating devices.

The 2406 is easy to set up for any desired sequencein the operation of up to four devices, with four levelsof operation available for each device. As levelsincrease, or decrease, all of the previous level outputsare de-activated. Simply observe the last level LED whichis on, follow the row of switches to the right and observewhich units are on.

Long life LED's on the front panel provide readily visibleindication of the status of each pump and level.

Up to four standard Model 2406 Sequencers may beconnected together in series or parallel (or a combinationof both), to provide for control of up to 16 devices at four

levels, or four devices at 16 levels, or 8 devices at 8 levels.Special configurations are available; consult factory.

The unit is solidly constructed and uses low PowerCMOS Circuitry. It is designed for use in combinationwith the Essex Engineering Corporation Model 2410Pump Controller, although it can be used with floatswitches, controllers, etc. of other manufactures.

Technical details are shown on the reverse side ofthis bulletin.

MODEL 2406SEQUENCER





12 VDC + 10% 1200 mADC max.


CONTROL OUTPUTSNPN solid state output; 50 VDC @ 60 mADC max. per point; 4 outputs for unit operation; 1 output for cascadeoperation

INDICATORSLevel Output - amber LEDControl Output - red LED

REPRESENTED BY





MODEL 2407ALTERNATOR MODULE

. . . . Provides the capability to automatically alternate andsequence up to four pumps, blowers or other devices.

FEATURES� Variables are field programmable.

� Provides automatic or manual operation in increasing or decreasing order.

� Digital indication of lead unit.

� LED input and output status indicators.

� Front panel alternate sequence control.

� First on/first off OR first on/last off sequencing capability.

manual pushbutton on the instrument face. When inthe REMOTE mode, the unit can be alternated bythe use of an external device such as a time clock,pushbutton, etc..

The input indicator LED's will light as the variousinput contacts close allowing exact monitoring of thevarious levels. The output indicators will light aseach output is required. If an output device, such asa pump, is indexed OFF, and a contact input isprovided to the Alternator, the corresponding outputLED will flash at a slow rate indicating the unit isinoperative and allowing the sequence to skip thisunit. This feature will provide smooth uninterruptedsequencing of outputs by NOT having to wait for thenext level to activate because a unit is inoperative.

Also included are lead unit outputs to provide relayswitching capability for analog signals, or remoteindication of lead unit.

DESCRIPTION

The Model 2407 Alternator is a unit that provides forthe on-off sequencing of various devices such aspumps, blowers, etc.

The unit is extremely flexible with all of the set upparameters being customer settable via plugjumpers and/or switches mounted within the unit.These include first-on/first-off or first-on/last-offselection; sequencing in increasing or decreasingorder; unit operation as DUPLEX, TRIPLEX orQUADRUPLEX; operation as alternator, contactin/contact out, or level control unit with latch-upmode. In the level control mode such devices asfloat switches can be used as inputs and will providea level control system turning on the outputs insequence and holding them on WITHOUT the use ofexternal latching relays. When the STOP level floatopens, all the outputs will be turned off.

Front panel controls provide the operator with theability to manually select the alternate mode ofoperation. When indexed to INTERNAL, the unit willalternate the sequence of operation when the lastlevel is de-energized. When indexed OFF,alternation will not occur, except for use of the


REPRESENTED BY


ELECTRICAL CONNECTIONS MODEL 2407 SPECIFICATIONS



12 VDC + 10% 1200 mADC max.


CONTROL OUTPUTSNPN solid state output; 50 VDC @ 60 mADC max. per point; 4 outputs for unit operation; 4 outputs for lead unitindication/control

INDICATORSLead unit - 0.4" LED digitInput - amber LEDOutput - red LED



. . . . A reliable, versatile unit designed specifically for control and monitoring of pumps, tanks, basins, etc...

FEATURES� Extremely accurate, repeatable and easy to use.

� Each output may be individually programmed for PUMP UP or PUMP DOWN operation.

� Digital indication of process variable and setpoints in desired engineering units.

� Setpoints are adjusted from front of instrument via 25-turn potentiometers.

� LED output status indicators.

� Standard and optional time delays are available tooverride system surging during operation and startup.

DESCRIPTION

The Essex Engineering Model 2410 Pump Controlleris designed specifically for controlling the filling andemptying of tanks, vats or basins by means of one ormore pumps. It accepts standard input signal levelsof 1-5 VDC, 4-20 mADC and special ranges from acontinuous level or pressure transmitter.

The incoming analog process signal is displayed onthe front of the instrument via a 3-1/2 digit LEDreadout. This same display is also used to set thevarious turn on and turn off points for the control andalarm functions.

Four outputs are available to activate remote relays.Each has an independent turn-on/turn-off setting of 0 to 100% of full scale. A unit indicator lamp isilluminated when its output is energized. Turn-on andturn-off points are set by means of their associated25-turn potentiometers on the face of the instrument.Each point is set via the read and selectpushbuttons which will illuminate a red bar adjacentto the potentiometer being calibrated. The outputrelays are remote and use low voltage control inorder to avoid high voltage transients when the linevoltage devices are switched on and off.

Fill/empty action is field selectable for each controlpoint via slide switches within the unit. Three alarms,two of which have an LED indicator, are provided.These are high and low level with the signal losscausing the low level LED to flash when activated.The 2410 Controller may be field programmed, viainternal DIP switches, to deenergize the controloutputs when any alarm condition occurs. Anexternal input signal is also available to deactivatethe control and/or alarms when activated.

Standard with the unit is a t ime delay, f ieldadjustable from 0.2 to 60 seconds, to inhibit controland alarm action on power up. This allows systemparameters to stabilize before the controller initiatesa response. Optional time delay boards are alsoavailable to provide various timing functions.

MODEL 2410PUMP CONTROLLER





12 VDC + 10% 1200 mADC max.

ANALOG INPUTS4-20 mADC @ 250Ω impedance1-5 VDC @ 470KΩ impedanceFactory specials

ANALOG OUTPUTSStandard has NONE. Optional: Isolated 4-20mADC @ 0-800Ω LOAD


CONTROL OUTPUTSNPN solid state output; 50 VDC @ 60 mADC max. per point; 4 outputs for unit operation; 3 outputs for alarmindication; 1 output for horn or external alarm indication.

INDICATORS3-1/2 digit, 0.56" LED type displayControl Output - amber LEDAlarm Output - red LED

REPEATABILITY & ACCURACY0.2% of span, + 1 of least significant digit

TIME DELAYS0.2 to 60 second field adjustable time delay is provided forcontrol and alarm functions to inhibit outputs when unit is initiallypowered. An optional 0.2 to 60 second, or special range, fieldadjustable time delay is available for OFF-ON and ALARMtiming.



REPRESENTED BY



. . . . A reliable, versatile unit designed for duplex control and alternation for basins, wetwells, tanks, etc...

DESCRIPTION

The Essex Engineering Model 2411 Duplex PumpController is designed specifically for controlling thefilling and emptying of tanks, vats or basins bymeans of two pumps. It accepts standard inputsignal levels of 1-5 VDC, 4-20 mADC and specialranges from a continuous level or pressuretransmitter.

The incoming analog process signal is displayed onthe front of the instrument via a 3-1/2 digit LEDreadout.This same display is also used to set thevarious turn-on and turn-off points for the control andalarm functions.

Two outputs are available to activate remote relays.Each has an independent turn-on/turn-off setting of 0 to 100% of full scale. A unit indicator lamp isilluminated when its output is energized. Turn-on andturn-off points are set by means of their associated25-turn potentiometers on the face of the instrument.Each point is set via the read and selectpushbuttons which will illuminate a red bar adjacentto the potentiometer being calibrated. The lead unitis indicated via green LEDʼs which are adjacent tothe #1-Alternate-#2 selector switch. The switchprovides manual override of the alternation cycle.

Fill/empty action is field selectable for each controlpoint via slide switches within the unit. Three alarms,two of which have an LED indicator, are provided.These are high and low level with the signal losscausing the low alarm LED to flash when activated.The 2411 Controller may be field programmed, viainternal DIP switches, to deenergize the controloutputs when any alarm condition occurs. Externalinputs are available to deactivate the control and/oralarms or provide alternation via a push button ortime clock contact.

Standard with the unit is a t ime delay, f ieldadjustable from 0.2 to 60 seconds, to inhibit controland alarm action on power up. This allows systemparameters to stabilize before the controller initiatesa response. Optional time delay boards are alsoavailable to provide various timing functions.

MODEL 2411DUPLEX PUMP CONTROLLER

FEATURES� Extremely accurate, repeatable and easy to use.

� Each output may be individually programmed for PUMP UP or PUMP DOWN operation.

� Digital indication of process variable and setpoints in desired engineering units.

� Setpoints are adjusted from front of instrument via 25-turn potentiometers.

� LED output status indicators.

� Standard and optional time delays are available tooverride system surging during operation and startup.





12 VDC + 10% 1200 mADC max.


ANALOG OUTPUTSStandard has NONE. Optional: Isolated 4-20mADC @ 0-800Ω LOAD


CONTROL OUTPUTSNPN solid state output; 50 VDC @ 60 mADC max. per point; 2 outputs for unit operation; 3 outputs for alarmindication; 1 output for horn or external alarm indication.

INDICATORS3-1/2 digit, 0.56" LED type displayControl Output - amber LEDAlarm Output - red LED


TIME DELAYS0.2 to 60 second field adjustable time delay is provided forcontrol and alarm functions to inhibit outputs when unit is initiallypowered. An optional 0.2 to 60 second, or special range, fieldadjustable time delay is available for OFF-ON and ALARMtiming.

REPRESENTED BY





. . . . Utilizes analog signals to provide automatic or manual control of various devices.

FEATURES� 31/2 digit LED display provides large, easy to read

digital indication of process.

� Digital readout of process variable in engineeringunits or 0 to 100.0%.

� Ten turn potentiometer provides fine tuningof manual set point.

� AUTO/MANUAL push button with "READ" push button provides for a manual bumpless transfer.

� Isolated 4 to 20 mADC output.

� Available for use with 120 VAC,12 or 24 VDCpower.

DESCRIPTION

The Essex Model 2415 Manual Loading Station is aconservatively designed, reliable unit that provides a4 to 20 mADC output which is directly proportional toa voltage or current input. When in the AUTOMATICmode, the output is directly proportional to the input,and the digital display will indicate the AUTO inputsignal. While in the AUTOMATIC mode, when theREAD button is depressed, the digital display willthen indicate the MANUAL value. By manipulatingthe SET potentiometer the MANUAL value can bemade to equal the previously noted AUTO inputsignal, thereby providing a "bumpless" transfer.

Conversely, when in the MANUAL mode, the digitaldisplay indicates the manual set point. Bydepressing the READ button, the digital display willshow the AUTO input signal. By releasing the buttonand adjusting the SET potentiometer, the MANUALsignal can be made to equal the previously notedAUTO signal. Therefore, when going from or toAUTO or MANUAL operation, bumpless transfer canbe achieved.

MODEL 2415MANUAL LOADING STATION




POWER INPUT120 VAC + 10% 15W max.24 VDC + 10% 650 mADC max.12 VDC + 10% 1200 mADC max.

CONTROL INPUT IMPEDANCE1 TO 5 VDC = 1 megohm4 to 20 mA DC = 250 ohm

CONTROL OUTPUT4 to 20 mADC isolated @ 0-800 ohm load

INDICATOR3-1/2 digit, 0.56" LED type display

REPEATABILITY AND ACCURACY0.2% of span + 1 digit

AVAILABLE OPTIONThe Model 2415 can be provided as a manualunit only, without the READ button and AUTO/MANUAL switch. It merely provides a 4 to20 mADC output signal.





REPRESENTED BY

. . . . Utilizes analog signals to provide automatic or manual control of various devices.

DESCRIPTION

The Essex Model 2416 Manual Loading Station is aconservatively designed, reliable unit that provides a4-20 mADC output which is directly proportional to avoltage or current input. Data conversion is veryaccurate, done via 12-bit A/D and D/A modules.

When in the AUTO mode, the output is directlyproportional to the input, with the large upper digitaldisplay indicating the process variable and the smalllower display indicating the percent output. Transferfrom AUTO to MANUAL is bumpless with no changein the output. The output can then be increased ordecreased via the UP and DOWN pushbuttons.Transfer from MANUAL to AUTO utilizes a fieldsettable ramp time, or the output may be manuallychanged to match the input, via pushbuttons.

The unit contains several field selectable variablessuch as ramp time from 0.2 to 64 seconds for a zeroto one hundred percent output change and zero

or non-zero reset on power up. Transferring between AUTO and MANUAL modes is accomplished via theAUTO/MANUAL pushbutton. Indicators are providedto display in which mode the controller is operating.

Also available in the unit are several optionalfeatures. They include MANUAL ONLY, which hasno analog input, no AUTO mode capability, and bothdisplays read the output; or MANUAL ONLY WITHPV, which is the same as the standard unit, bit withno AUTO mode capability.

MODEL 2416MANUAL LOADING STATION

FEATURES� 31/2 digit LED displays provides large,

easy to read digital indication of both process variable and output signals.

� Digital indication of process variable in desired engineering units.

� AUTO to MANUAL bumpless transfer.

� MANUAL to AUTO field settable timed ramping.

� Isolated output.

� Pushbutton increase/decrease control in MANUAL mode.




REPRESENTED BY




12 VDC + 10% 1200 mADC max.

ANALOG INPUTS (standard, except with Manual Only option)4-20 mADC @ 250Ω impedance1-5 VDC @ 470KΩ impedanceFactory specials

CONTROL OUTPUTSIsolated 4-20mADC @ 0-800Ω LOADSPDT relay contact for AUTO/MANUAL status; 0.5A @ 120VAC

RAMP TIMING0.2 to 64 seconds in 7 selectable steps for 0-100% output

INDICATORSProcess - 3-1/2 digit, 0.56" LED type displayOutput - 3-1/2 digit, 0.3" LED type display


AVAILABLE OPTIONSManual only - Unit provides a 4-20 mADC output signal, usingboth readouts as OUTPUT display Manual only with PV - Unit provides a 4-20 mADC outputsignal, using Process readout as PROCESS display and smallreadout as OUTPUT display



. . . . Provides ease of use and flexibility in chemical feed systems.

FEATURES� Provides precision control over the process.

� Competitively priced.

� Parallel indicating vertical edge meters allowdirect comparison between input and output.

� Digital thumbwheels provide for accurateset points.

DESCRIPTIONThe Essex Engineering Model 2420 Ratio StationModule is a ratio controller that allows the preciseratioing of input and output signals on a continuousbasis. It is designed to be used in water treatmentplants and in the chemical processing industry. Itoffers the ability to control such items as chemicalfeed equipment, paced from flow, pressure or othertype signals, by a multiplication factor of 0.1 to 3.9times the input level.

Standard indication of the ratios is by means of two31/2" vertical edge meters, calibrated 0-100%.Custom scales are available for special applications.

Both the standard input and output signals are4-20 mADC, with the ratio being selected by meansof two digital thumbwheels. The ratio range is 0.1 to 3.9,selected in 0.1 step increments, with the accuracy being0.2% of span.

The Model 2420 Ratio Station is designed to beused with the other units in the Essex 2400 seriescontrollers, although it is feasible to incorporate theunit with controllers of other manufacture. Consultthe factory for proper application and/or specialinputs, outputs and scales.

MODEL 2420RATIO STATION MODULE





12 VDC + 10% 1200 mADC max.


ANALOG OUTPUTS4-20mADC @ 0-800Ω LOADOptional: Isolated 4-20mADC @ 0-800Ω LOAD

STANDARD INDICATORS31/2" vertical edge input meter; 0-100% scale31/2" vertical edge output meter; 0-100% scale

REPEATABILITY AND ACCURACY0.2% of span

RATIO SETPOINT0.1 to 3.9 - Set by two digit thumbwheel switches in

0.1 increments

AVAILABLE OPTIONSConsult factory

REPRESENTED BY





DESCRIPTION

The Essex Engineering Model 3905 DuplexElectronic Alternator is a modular unitdesigned to be used between the Model2410 Controller and the Series 3800 relaycard. Its modular construction provides foreasy replacement and/or trouble shooting.It plugs into a standard eight pin socket.The unit has two LED's on the cover toindicate which output will be LEAD onthe next activation.

MODEL 3905DUPLEX ALTERNATOR



7

6

5

2

1 8

3

4 Lead input

+24VDC

+24VDC

Output #2

Output #1

Lag input

COM

Model 2410 ControllerOutput

Series 3800Relay Card

} }MODEL 3905 SPECIFICATIONS


POWER INPUT24 VDC + 10% 15mA maximum

MODULE INPUTSContact closure from either pin 5 or 6 to COM15VDC @ 1mA maximum

MODULE OUTPUTSNPN transistor output 50VDC @ 60mA maximum

PHYSICAL DIMENSIONS2.375(W) x 1.75(D) x 3.00(H), base to top of LED

. . . . A reliable, modular unit designed specifically for use with the Model 2410 Controller to provide alternation.



REPRESENTED BY

. . . . A reliable, modular unit designed specifically for providing loop power for instrument systems.

DESCRIPTION

The Essex Engineering Model 3907Loop Power Supply is designed toprovide 24VDC loop power for electronictransmitters. It is designed as a modularunit which plugs into a standard eight pinsocket. This facilitates easy replacementand/or trouble shooting by simplyunplugging the unit. An LED on the unitcover indicates the presence of 24VDCat the designated pins. With it's 100mADC output capability, it can power upto five (5) 4-20 mADC instrument loops



POWER INPUT120 VAC + 10% 2W Max.

POWER OUTPUT24 VDC @ 100mANL/FL = 0.2%Ripple = 8MV P-P @ Full LoadThe output is short circuit protected for momentary shorts.However, a sustained short circuit may damage or burn-outthe power supply.

PHYSICAL DIMENSIONS2.375(W) x 1.75(D) x 3.00(H), base to top of LED


7

6

5

2

1 8

3

4

24VDC @100mA

120 VAC

NOTES1. 24 VDC is also available at terminal 1 (common)

and terminal 8 (+).

2. 120 VAC power source to power supply module should contain a 1/8 A. slo-blow fuse for electrical overload protection.

NH

COM +

MODEL 3907LOOP POWER SUPPLY



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ESSEX ENGINEERING CORPORATION

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