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5.2.1 ON SITE CALIBRATION EQUIPMENT REQUIRED
For qualified personnel, the following is a recommended list of calibration equipment required.
•
A digital multi-meter with a range of 20.0 mA or more and 200 mV or more.
•
A "Remote Calibration Lead" (P/N 2900-01) for the above meter ( available from AMC )
•
A set of leads with clip on probes for the above meter
•
Miniature screwdriver trimmer adjustment tool
•
Calibration adapter, available from AMC
•
Zero & Span gases ( contact AMC for information )
•
Clean, low static cloth or tissue to cover sides of sensor during calibration
5.2.2 CALIBRATION PROCEDURE
The transmitter is equipped with a remote calibration feature allowing for one-man calibration at
the transmitter location. The transmitter output is measured using the plug-in type "Remote
Calibration Lead". In most cases it is only Zero and Span adjustments that are made in field
calibrations.
Note:
The calibration procedure may cause false alarm and or fail signal.
precautions may be required.
Refer to Figure 6 to perform the following calibration procedure:
1) Remove cover from transmitter housing.
2) Attach and set the multi-meters as shown.
3) Cover the sides of sensor with a clean cloth or similar to prevent a draft on the
sensor.
4) Apply a Zero gas sample, with a calibration adapter cup firmly and completely over
the sensor opening on side of AMC-2751 for 2 minutes with a flow rate of .5 liters per
minute.
5) At 2 minutes adjust the Zero trimmer for a zero current of 4.00 mA +/- .1ma. Note
that the zero current may give a signal representing a gas concentration as high as
2ppm depending on the zero gas used.
6) Apply the Span gas sample, with a calibration adapter cup firmly and completely over
the sensor opening on side of AMC-2751 for 2 minutes with a flow rate of .5 liters per
minute.
7) At 2 minutes adjust the Span trimmer for the Span current reading of 20 ma +/- .16
mA.
AMC-2751 Transmitter & Sensor
12
Appropriate
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