Transmitter Calibration/Verification Procedure; Recalibration - AMC 350 Instructions Manual

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5.2.2 TRANSMITTER CALIBRATION/VERIFICATION PROCEDURE

The calibration procedure may cause the monitoring equipment to give a false alarm; therefore

appropriate precautions should be taken.

included with every Calibration Kit or available separately on request (depending on type of gas

or application). Refer to FIGURE 6 for the Calibration/Verification setup.

1. Remove cover from transmitter housing.

2. Connect "Remote Calibration Lead" to multimeter. BLACK lead to negative or common

(–). RED lead to positive (+) on mA scale.

3. Switch ON multimeter and select a DC milliamp range greater than 20 mA full scale.

Insert plug end of "Remote Calibration Lead" fully into CAL jack on transmitter cover

plate.

5. Apply a Zero gas sample or with the sensor in clean air or while covering the open end

of the sensor, check for a stabilized zero signal of approximately 4 mA.

6. Apply a Span gas sample. Since the transmitter output range is 4 to 20 mA, a full-scale

concentration should register 20 mA after a few moments exposure.

There are two adjustments to be made for periodic recalibration: Zero and Span.

Zero:

With the sensor in Zero Gas, the transmitter output signal current should read 4 mA.

This is obtained by adjusting the Zero trimmer on the transmitter for a voltage of

0.000 VDC at the test points in Figure 6. It is possible, under certain conditions that

the Zero current will fall below 4 mA.

Span:

While the sensor is exposed to the calibration gas sample, adjust the Span trimmer on

the transmitter to set the transmitter output signal current proportional to the applied

gas concentration.

AMC-350 Sensor/Transmitter

Instructions for introducing the gas sample are

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