65-2340RK Toxic Gas Transmitter • 19
Preparing for Calibration
1. Place the controller into its calibration mode or disable external alarms.
2. Unscrew and remove the junction box cover.
3. Set a voltmeter to measure in the millivolt (mV) range.
4. Plug the voltmeter leads into the test points on the amplifier. Plug the positive lead into the
red + test point; plug the negative lead into the black - test point.
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 and a fullscale setting of 1.00, the
correct output is 300 mV.
300(mV) = (.50/1.00) X 400 +100
NOTE:
Calibrating the toxic gas transmitter may cause alarms. Be sure to put the controller
into its calibration program or disable external alarms before continuing.
6. Unscrew the splashguard from the detector housing cap. Make sure the cap remains
securely screwed onto the housing body.
7. Push the calibration cup onto the plug-in sensor that sticks through the housing cap. The
calibration cup seals to the sensor with an O-ring.
Setting the Zero (Fresh Air) Reading
NOTE:
If you can verify that the toxic gas transmitter is in a fresh air environment, you do not
need to apply zero air to the detector before adjusting the fresh air reading.
1. Screw the regulator into the zero air calibration cylinder.
2. Use the sample tubing to connect the regulator to the calibration cup. Make sure to
connect the tube to the inlet side of the calibration cup if using the 81-1138RK calibration
cup which is marked on the outside bottom to show the required flow direction through
the cup.
3. Turn the regulator knob counterclockwise to open the regulator.
4. Allow the gas to flow for two minutes and verify a reading of 100 mV (±2 mV). If
necessary, use the zero pot on the amplifier to adjust the reading to 100 mV (±2 mV).
5. Turn the regulator knob clockwise to close the regulator.
6. Unscrew the regulator from the zero air calibration cylinder. Leave the sample tubing
connected to the regulator and the calibration cup.
