RKI Instruments 35-3010RKA-02 - Manual (Page 27)

35-3010RKA-02 Sample-Draw Detector • 23
3. Connect the sample tubing from the regulator to the inlet line at or near the INLET
fitting.
4. Allow the gas to flow for one minute.
5. Verify a voltmeter reading of 434 mV ± 2 mV at the test points as described in the
Preparing for Calibration section above.
6. If necessary, use a small flat-blade screwdriver to adjust the zero pot until the
voltmeter reading is 434 mV ± 2 mV.
7. Disconnect the sample tubing from the inlet line.
8. Unscrew the regulator from the zero air calibration cylinder. Leave the sample tubing
connected to the regulator.
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 Detector
This section describes how to calibrate the H
2
S detector in the sample-draw detector. It
includes procedures to prepare for calibration, set the zero reading, set the response
reading, 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 H
2
S channel.
3. 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.
4. Use the following formula to determine the correct test points output for the 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