Bacharach H25-IR manual mA Current Loop Connection, MA Current Loop Connector

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H25-IR	Preparing for Operation

2.8 4–40 mA Current Loop Connection

An external 4−20 mA monitoring device (e.g., chart recorder) can be connected to the H25-IR using a shielded-twisted-pair cable.

IMPORTANT! The monitoring device must be isolated from ground (floating).

Locate the 4−20 mA connector on the rear of the unit (refer to Section 1.7.2 Rear View), and then remove the resistor or shorting wire from its terminals.

NOTE: A 100 ohm, ¼ W resistor must be connected to the 4–20 mA connector if no external monitoring device is used. Failure to install this resistor will cause a “Loop Open Error” to occur (refer to Section “4.3 What to Do when a Fault Occurs”).

Secure the wire leads from the external monitoring device to the connector as shown in the diagram below, making sure that the polarity at this connector matches the wiring at the monitoring device.

4–20 mA Current Loop Connector

CAUTION: Never apply power to the 4–20 mA Current Loop Connector from an external power supply. In addition, connect only a load resistor or a floating measurement device.

The default current-to-ppm factor is set to 0.016 mA = 1 ppm, providing a measurement range of 0 ppm (4 mA) to 1,000 ppm (20 mA). Note that the current-to-ppm factor can be changed using the instrument’s LOOP function (refer to Section 2.4.4 4–20mA Loop).

To facilitate loop zero and span checking, note that when the LOOP function is selected the loop output is set to 20 mA, and upon exiting this function the loop output is set to 4 mA.

Instruction 3015-4342

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Contents Infrared Refrigerant Gas Leak Detector H25-IRRegister Your Warranty by Visiting WarrantyTable of Contents Parts and Service Introduction Safety PrecautionsHazard Symbols AC Power and GroundingMisuse and Modifications to Instrument Case of Malfunction CleaningExplosive Atmosphere Working Inside the InstrumentUnpacking and Initial Checks Ordering InformationFeatures and Capabilities Leak Rate = Flow Rate x Gas Concentration Functional OverviewFront View Names and Functions of ComponentsRear View Interior Standard Probe with LED and Programmable Pushbutton Standard ProbeSmart Probe Smart Probe Keylock Function System Menu Menu SystemTurning on the Instrument Connecting the ProbeConnecting the AC Power Cord Preparing for OperationLeak Units System SetupMain Menu System Setup Menu Gas Type4 4-20 mA Loop RelaysClock Pchk ModeReset Defaults BrightnessRange Configuring the Setups FunctionSetup Name Setpoint Feedback ModeSearch Auto Zero CalibrationExternal Relay Connections Typical Relay 1 Wiring4-40 mA Current Loop Connection MA Current Loop ConnectorPreparing for Operation H25-IR Calibration Data Menu CalibrationSelecting Internal or External Calibration Internal Calibration SelectionExternal Calibration Selection and Setup Internal Calibration CALExternal Calibration Material Required ProcedureCAL Factor Improving PPM Measurement Accuracy using the CAL Factor Restoring Factory Calibration Adjusting the CAL FactorCalibration H25-IR Operation Using the H25-IRPower Initial SetupRange Selection Setup SelectionSearching for a Leak Volume AdjustmentMeasuring the PPM Level Measuring the Leak RateLog Menu Logging Measured ReadingsWorking with Logged Measurements Clearing the Log RS-232 Communication What to Do when a Fault OccursWhat is PCHK? Diagnostics MenuOperation H25-IR Sensor Data MaintenanceDiagnostics Menu Last Fault Factory Factory Menu Factory MenuIR Emitter PressureLeak Temp Auto GainLeak Rate Leak GasSensor Cal Leak TempcoFirmware Model SelectProbe Type Items Required Flashing MemorySelect Setup Communications Select File Load Flash Image Removing the Top Cover Part ReplacementProbe Tip Filter & O-Ring Replacement Fuse ReplacementInternal Filter Replacement Replacement Parts Parts and ServiceUnited States Service CentersCFCs, HCFCs, HFCs and Halogens SpecificationsSpecifications H25-IR Continuous Appendix a Factory DefaultsAppendix a H25-IR H25-IR Appendix a Headquarters Hunt Valley Circle, New Kensington, PA