65-2422RK-05 H
2
S Transmitter • 19
5. Remove the junction box cover, then plug the voltmeter leads into the test points on the
amplifier.
Plug the positive lead into the test point labeled
TP+
; plug the negative lead into the test
point labeled
TP-
.
6. 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 25 PPM H
2
S and a fullscale setting of 100 PPM,
the correct output is 200 mV.
200 (mV) = (25/100) X 400 +100
Setting the Zero Reading
NOTE:
If you can verify that the H
2
S transmitter is in a fresh air environment, you do not
need to apply zero air to the detector before adjusting the zero reading.
1. Turn the regulator on/off knob counterclockwise to open it. Gas will automatically begin
to flow.
2. Allow the gas to flow for two minutes.
3. Verify a reading of 100 mV (± 2mV).
4. If necessary, use the zero pot on the amplifier to adjust the reading to 100 mV (± 2mV).
5. Unscrew the regulator from the zero air calibration cylinder.
Leave the sample tubing connected to the regulator and the calibration cup.
Setting the Response Reading
1. Verify that the calibration gas is representative of the transmitter’s target gas.
2. For toxic gas cylinders (like H
2
S), it is important to vent the regulator while installing it
onto the cylinder. Venting the regulator during installation helps prevent air from getting
into the cylinder and degrading the gas. Open the regulator by turning the knob
counterclockwise and then install it onto the cylinder.
3. Allow the gas to flow for two minutes.
4. Verify that the reading matches the response reading (± 2mV) you determined earlier.
5. If necessary, use the span pot on the amplifier to adjust the reading to match the correct
response reading.
6. Turn the regulator on/off knob clockwise to close it.
7. Unscrew the regulator from the calibration cylinder.
8. Unscrew the calibration cup from the detector.
