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65-2670-XX-04 M2A Transmitter Operator’s Manual
6. When you first start to notice an increase in the gas reading, note how much time passed between
starting the gas flow and noticing a reading response.
7. Turn the regulator’s on/off knob clockwise to close the regulator.
8. Unscrew the regulator from the calibration cylinder.
9. 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.
10. Add 1 minute to the length of time determined in step 6. This is the response time for the detector.
When performing a zero adjustment or span adjustment, gas must be applied for this length of
time.
Calibration
This section describes how to calibrate the M2A transmitter. It includes procedures to prepare for
calibration, enter Calibration Mode, adjust the fresh air (zero) setting, adjust the span setting, and
return to normal operation.
WARNING:
The M2A is not an active gas monitoring device during the calibration procedure.
The 4-20 mA output signal will “freeze” at 3.5 mA and all relays will remain in their
non-alarm state while the M2A is in Calibration Mode. The output signal will not
indicate current readings and the relays will not resume operating normally until the
M2A is in normal operation again.
NOTE:
The detector must be calibrated with a gas concentration between 10% and 100% of the
channel’s full scale value (ie. a 0 - 500 ppm NH
3
detector must be calibrated with an NH
3
concentration between 50 ppm and 500 ppm).
NOTE:
While in the calibration program, if there is no switch activity for the calibration time-out
period the unit will return to normal operation. See “Viewing & Changing M2A
Parameters” on page 29 for instructions to set the calibration time-out.
Special Note About Calibrating a ClO
2
Detector
RKI Instruments, Inc. recommends using a ClO
2
generator to set the ClO
2
detector’s response reading.
The flow rate on the generator needs to be set to 0.5 LPM and RKI Instruments, Inc. recommends that
0.5 ppm ClO
2
be used. If a ClO
2
generator is used for calibration, the steps related to the use of a
calibration gas cylinder in the instructions below can be disregarded.
Non-Intrusive Calibration
If the M2A is installed in a classified area and non-intrusive calibration is required, follow the
instructions below, but do not remove the junction box cover. Use the magnetic wand accessory to
actuate the magnetic switches instead of pushing the control switch buttons. To actuate a magnetic
switch and perform the same operation as pressing a control switch button, touch the magnet in the end
of the magnetic wand to the M2A’s glass cover directly above the magnetic switch you wish to actuate.
