65-2435RK CO Transmitter • 19
NOTE:
Do not screw the regulator into the zero air calibration cylinder at this time.
3. Set a voltmeter to measure in the millivolt (mV) range.
4. 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-
.
5. 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 PPM CO and a fullscale setting of
300 PPM, the correct output is 167 mV.
167 (mV) = (50/300) X 400 +100
NOTE:
Calibrating the CO transmitter may cause alarms. Be sure to put the controller into its
calibration program or disable external alarms before continuing.
Setting the Zero Reading
NOTE:
If you can verify that the CO transmitter is in a fresh air environment, you do not need
to apply zero air to the detector before adjusting the zero reading.
1. Screw the regulator into the zero air calibration cylinder. Gas will automatically begin to
flow.
2. Allow the gas to flow for two minutes, then verify a reading of 100 mV (± 2mV). If
necessary, use the zero potentiometer on the amplifier to adjust the reading to 100 mV (±
2mV).
3. 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. Screw the regulator into the calibration cylinder. Gas will begin to flow.
2. Allow the gas to flow for two minutes, then verify that the reading matches the response
reading (± 2mV) you determined earlier. If necessary, use the span potentiometer on the
amplifier to adjust the reading to match the correct response reading.
3. Unscrew the regulator from the calibration cylinder.
