36
•
Chapter 7: Maintenance
65-2646RKS-SW M2A Transmitter Operator’s Manual
Calibration Frequency
Although there is no particular calibration frequency that is correct for all applications, a
calibration frequency of every 3 to 6 months is adequate for most carbon monoxide transmitter
applications. Unless experience in a particular application dictates otherwise, RKI Instruments,
Inc. recommends a calibration frequency of every 3 months.
If an application is not very demanding, for example detection in a clean, temperature controlled
environment where carbon monoxide is not normally present and calibration adjustments are
minimal at calibration, then a calibration frequency of every 6 months is adequate.
If an application is very demanding, for example if carbon monoxide is present often and in
significant concentrations or the environment is not well controlled, then more frequent
calibration than every 3 months may be necessary.
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.
Slow or No
Response/
Difficult or
Unable to
Calibrate
• Unable to
successfully set the
fresh air or span
reading during
calibration.
• M2A requires
frequent calibration.
NOTE:
See
“Calibration
Frequency” on page 36
for calibration
frequency guidelines.
• The calibration
cylinder is low, out-
dated, or defective.
• The calibration gas
flow rate is too low.
• The calibration gas is
not an appropriate
concentration.
• The detector is
malfunctioning.
• The terminal PCB is
malfunctioning.
1. Verify that the calibration cylinder
contains an adequate supply of a
fresh test sample.
2. Verify that the regulator used for
calibration is a 0.5 LPM regulator.
3. Verify that the calibration gas
concentration is appropriate for the
transmitter. The concentration
should be in the detection range,
preferably about half of the detection
range.
4. If the calibration/response
difficulties continue, replace the
detector.
5. If the calibration/response
difficulties continue, contact RKI for
further instruction.
Table 7: Troubleshooting the Carbon Monoxide Detector (Continued)
Condition
Symptom(s)
Probable Causes
Recommended Action
