36
65-2640RK-05-04 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 combustible gas
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 combustible gas 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 combustible gas 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. If potential catalyst poisons are known
or likely to be present, more frequent calibration than every 3 months will be necessary.
Determining Response Time
Since the detector junction box is installed remotely from the M2A, the response time of
the detector will depend on the length of flexible tubing that is attached to the calibration
adapter/splash guard. To determine the response time based on the length of tubing
connected:
1.
Place the M2A into its calibration mode or disable external alarms.
2.
Note the current gas reading displayed at the M2A.
3.
Screw the regulator into the calibration cylinder. Do not use a zero air cylinder for this
operation.
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.
• The flexible tubing
to the calibration
adapter/splash
guard has become
kinked, blocked, or
disconnected.
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. Verify that the flexible tubing to
the calibration adapter/splash
guard is clear and connected to
the calibration adapter/splash
guard.
5. If the calibration/response
difficulties continue, replace the
detector.
6. If the calibration/response
difficulties continue, contact RKI
for further instruction.
Table 7:Troubleshooting the Combustible Gas Detector (Continued)
Condition
Symptom(s)
Probable Causes
Recommended Action
