AirTest TR-1000 Operation & Maintenance Manual - Page 3
Browse online or download pdf Operation & Maintenance Manual for Accessories AirTest TR-1000. AirTest TR-1000 6 pages. 4-20 ma sensor / transmitter, vehicle exhaust detection applications
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4. TO SET ZERO OFFSET
Before proceeding, it is critical that the sensor is exposed to clean air. If
clean air cannot be assured, a sample of clean air, or "Zero" gas should be
applied to the sensor. Monitor the OUTPUT test point - TP3 (Yellow) - and
adjust the ZERO OFFSET potentiometer - RV3 - so the meter reads 0.4 volts
(this is equivalent to 4 mA).
NOTE: The 4 to 20 mA loop must be complete.
5. TO SET SPAN
While still monitoring the OUTPUT test point - TP3 (Yellow), apply a sample
of gas consisting of the target gas mixed with air. The concentration of the
gas should be the same as the desired full scale of the TR-1000.The flow rate
of the gas must be 0.2 liters/minute. Adjust the "GAIN" trimpot - RV2 – so the
meter reads 2.0 volts. (This is equivalent to 20 mA)
The sensor is now calibrated for "zero" and "span".
It is recommended that sensor calibration be carried out on an annual basis.
NOTE: THESE SENSORS VARY WITH HUMIDITY, PROTECT THE SENSOR
FROM WIND AND AIRFLOWS.
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