35-3010RK-01 Sample-Draw Detector • 21
5.
Set the fresh air reading according to the controller operator’s manual.
Returning to Normal Operation
1.
Reconnect the incoming sample line.
2.
Wait 1 to 2 minutes to allow the calibration gas to be drawn out and the reading to
stabilize.
3.
Close the housing door.
4.
Store the components of the calibration kit in a safe and convenient place.
Calibration, H
2
S and CO Detectors
This section describes how to calibrate the H
2
S and CO detectors in the sample-draw
detector. It includes procedures to prepare for calibration, set the zero reading for each
channel, set the response reading for each channel, and return to normal operation.
NOTE:
This procedure describes calibration using a demand flow regulator, a zero air
calibration cylinder, and a 4-gas calibration cylinder.
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. It will be used in the
calibration of the CO and H
2
S channels.
•
When checking the mV output of the CO channel, plug the voltmeter leads into
the test points in the AMP 1 section of the main circuit board. Plug the positive
lead into the test point labeled CAL+1; plug the negative lead into the test point
labeled CAL-1.
•
When checking the mV output of the H
2
S channel, plug the voltmeter leads into
the test points in the AMP 2 section of the main circuit board. Plug the positive
lead into the test point labeled CAL+2; plug the negative lead into the test point
labeled CAL-2.
3.
Use the following formula to determine the correct test points output for the CO and
H
2
S calibrating sample.
Output (mV) = (calibrating sample/fullscale) X 400 + 100
For example, with a calibrating sample of 25 ppm H
2
S and a fullscale setting of 100
ppm H
2
S, the correct output for the H
2
S test points is 200 mV.
200 (mV) = (25/100) X 400 +100
Setting the Zero Reading
1.
Screw the regulator into the zero air cylinder.
2.
Connect the calibration kit sample tubing to the regulator.
3.
Connect the sample tubing from the regulator to the inlet line at or near the INLET
