RKI Instruments 35-3010RKA-06 - Manual (Page 23)

35-3010RKA-06 Sample-Draw Detector • 19
Calibration
This section describes how to calibrate the sample-draw adapter. 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.
3. When checking the mV output of each channel, plug the voltmeter leads into the
appropriate test points.
For the LEL channel, plug the voltmeter leads into the test points on the LEL
transmitter. Plug the positive lead into the test point labeled TP+; plug the negative
lead into the test point labeled TP-.
For the H
2
S channel, plug the voltmeter 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
calibrating sample.
Output (mV) = (calibrating sample/fullscale) X 400 + 100
For example, with a calibrating sample of 50 %LEL methane and a fullscale setting of
100%LEL, the correct output for the LEL test points is 300 mV.
300 (mV) = (50/100) X 400 +100
Setting the Zero Reading
NOTE: If you can verify a fresh air environment, it is not necessary to use the zero air
calibration cylinder to set the zero reading.
1. Screw the regulator into the zero air calibration 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
fitting.
4. Allow the gas to flow for one minute.
5. Verify a voltmeter reading of 100 mV ± 2 mV at the test points for each channel as
described in the Preparing for Calibration section above.
6. If necessary, use a small flat-blade screwdriver to adjust the zero pot for the
appropriate channel until the voltmeter reading is 100 mV ± 2 mV.