35-3010A-09 Sample-Draw Detector • 21
Setting the Response Reading
1.
Screw the regulator into the methane calibration cylinder.
2.
Connect the sample tubing from the regulator to the inlet line at or near the sample-
draw detector’s INLET fitting.
3.
Allow the calibration gas to flow for one minute.
4.
Check the mV output on the CH
4
transmitter test points and verify that the reading
matches the response reading (±2 mV) you determined earlier.
5.
If necessary, use the span pot on the CH
4
transmitter to adjust the reading to match
the correct response reading.
6.
Disconnect the sample tubing from the sample-draw detector’s inlet line.
7.
Unscrew the regulator from the calibration cylinder.
NOTE:
For convenience, leave the regulator connected to the sample tubing.
Returning to Normal Operation
1.
Remove the voltmeter leads from the test points.
2.
Reconnect the incoming sample line.
3.
Wait 1 to 2 minutes to allow the calibration gas to be drawn out and the reading to
stabilize.
4.
Close the housing door.
5.
Store the components of the calibration kit in a safe and convenient place.
Calibration, Oxygen Detector
This section describes how to calibrate the oxygen detector in the sample-draw detector. It
includes procedures to prepare for calibration, set the zero reading, set the fresh air
reading, and return to normal operation.
NOTE:
This procedure describes calibration using a demand flow regulator, a zero air
calibration cylinder, and a 100% nitrogen calibration cylinder to set the zero
reading.
Preparing for Calibration
CAUTION:
This procedure may cause alarms at the controller. Take appropriate action to avoid
this, such as entering the calibration mode at the controller.
1.
Open the housing door.
2.
Set a voltmeter to measure in the millivolt (mV) range.
3.
Plug the voltmeter into the test points on the oxygen transmitter. Plug the positive
lead into the test point labeled TP+; plug the negative lead into the test point labeled
TP-
.
