22
65-2670-XX-04 M2A Transmitter Operator’s Manual
NOTE:
For all gases except ClO
2
: Allow the M2A’s detector to warm up for 15 minutes before you
continue with the next section, “Adjusting the Fresh Air Reading.”
For ClO2: All the M2A’s detector to warm up for 2-3 hours before you continue with the
next section, “Adjusting the Fresh Air Reading.”
Adjusting the Fresh Air Reading
When the M2A is shipped from RKI Instruments, Inc., it is factory calibrated. If a full calibration is
desired at startup, see “Calibration” on page 38.
Verify that the M2A is in a fresh air environment (environment known to be free of combustible or
toxic gas vapors and of normal oxygen content, 20.9%).
CAUTION: If you suspect the presence of the target gas in the monitoring environment, use the
calibration kit and the zero air calibration cylinder to introduce “fresh air” to the
detector and verify an accurate fresh air setting. See the “Calibration” on page 38 for
instructions on how to use a zero air cylinder when performing a fresh air
adjustment.
Non-Intrusive Fresh Air Signal Adjustment
If the M2A is installed in a classified area and non-intrusive zero adjustment 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 over the magnetic switch you wish to actuate.
Touching the glass and removing the wand is the same as pressing and releasing a button. Touching the
glass and keeping the wand in place is the same as pressing and holding a button.
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 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 29
for instructions to change the calibration time-out.
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?
.
Calib?
YES/NO
