65-2645-05SS-04 M2A Transmitter Operator’s Manual
37
2. 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.
3. Install the regulator onto the cylinder.
4. Allow calibration gas to flow for the length of time determined in “Determining Response Time” on
5. Turn the regulator knob clockwise to close it.
6. Unscrew the calibration gas cylinder from the fixed flow regulator. The M2A will continue to display the
maximum gas response on the display and retain the response level in its memory.
7. Adjust the gas reading up or down to match the calibration gas cylinder concentration by using the
UP/YES and DOWN/NO buttons, then press and release the ENTER button.
NOTE:
The detector must be calibrated with a gas concentration between 10% and 100% of the channel’s
full scale value (ie. between 10 ppm and 100 ppm H
2
S).
8. The M2A will perform a span operation. The display will indicate
SPAN Gas PASS
for a few seconds, then
indicate
SPAN Gas SAVED
before indicating
Leaving CAL Mode
for a few seconds.
NOTE:
If the span adjustment fails, see “Troubleshooting” on page 32 for recommended actions.
9. The display will now alternate between the normal operation screen and the message
REMOVE CAL GAS
for 1 minute. If the calibration gas has not been removed from the detector, remove it now to avoid
unwanted alarms.
During this 1 minute period, the signal output will remain fixed at 3.5 mA and the relays will remain in their
non-alarm state to avoid unwanted alarms while the calibration gas clears from the detector. At the end of
the 1 minute period, the
REMOVE CAL GAS
message will stop appearing and the M2A will return to
normal operation.
10. Disconnect the calibration adapter/splash guard’s flexible tubing from the regulator.
NOTE:
Do not disconnect the flexible tubing from the calibration adapter/splash guard.
11. Store the components of the calibration kit in a safe place.
Replacing Components of the H
2
S Detector
This section includes a procedure to replace the H
2
S plug-in sensor and the entire detector assembly. In most
cases, it is not necessary to replace the entire detector assembly.
Replacing the Plug-In H
2
S Sensor
CAUTION:
The sensor contains electrolyte which is a dilute acid. Do not disassemble the sensor when
replacing it with a new one. If sensor electrolyte comes in contact with your skin, wash affected
area thoroughly with soap and water.
1. Turn off or unplug power to the M2A.
2. Unscrew the calibration adapter/splash guard from the detector housing cap.
3. Unscrew the detector housing cap from the detector housing body. Make sure not to lose the cap gasket.
