36
M2A Transmitter Operator’s Manual
WARNING:
The M2A is not an active gas monitoring device during the fresh air adjustment procedure.
The 4-20 mA output signal will “freeze” at 3.5 mA for a toxic, combustible gas, or CO
2
M2A,
or at 17.4 mA for an oxygen M2A, 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:
While in the calibration program, if there is no switch activity for the calibration time-out period the
unit will return to normal operation. The factory set time-out is 15 minutes. If you want a different
time-out period, see “Viewing & Changing M2A Parameters” on page 42 for instructions to change
the calibration time-out.
Combustible Gas, CO
2
, and Toxic Versions, Adjusting the Fresh Air Reading
1. While in normal operation, press and hold the UP/YES button for 5 seconds to enter Calibration Mode.
Release the button when the following screen appears
.
2. Press and release the UP/YES button to continue. The display will indicate the target gas and
CAL Mode
for
a few seconds before showing
FreshAir Adjust?
.
3. Press and release the UP/YES button.
ENTER
will alternate with
FreshAir
on the top display line and the
current gas reading will be on the bottom display line.
4. Press and release the ENTER button. The M2A will perform a zero operation and the display will indicate
SPAN w/Cal Gas?
.
5. Press and release the DOWN/NO button. The display will indicate
Leaving CAL Mode
and the M2A will
return to normal operation.
Oxygen Version, Adjusting the Fresh Air Reading
1. While in normal operation, press and hold the UP/YES button for 5 seconds to enter Calibration Mode.
Release the button when the following screen appears.
2. Press and release the UP/YES button to continue. The display will indicate
OXYGEN CAL Mode
for a few
seconds before showing
FreshAir Adjust?
.
3. Press and release the UP/YES button.
ENTER
will alternate with
FreshAir
on the top display line and the
current oxygen reading will be on the bottom display line.
4. Press and release the ENTER button. The M2A will perform a span operation and then the display will
indicate
ZERO w/Cal Gas?
.
5. Press and release the DOWN/NO button. The display will indicate
Leaving CAL Mode
and the M2A will
return to normal operation.
Calib?
YES/NO
Calib?
YES/NO
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