AMC-200 Transmitter
7
5 OPERATION AND CALIBRATION
5.1 OPERATION
The AMC-200 series sensor/transmitter unit is factory calibrated for the gas listed in section 2.2,
Factory Settings, at the beginning of this manual. The unit should not need recalibration when
first installed and powered-up, but a test for correct operation is recommended after a
stabilization period of 10 minutes.
In general, after the stabilization period, the transmitter should be sending (in a clean air
environment) a signal of approximately 4 mA to the monitor or controller. However, there are a
few situations where a slightly higher or lower than normal signal may be noticed. In many
facilities there are residual background gases (including the gas being detected) in the air at all
times. These can cause a minor response from the sensor, normally causing a rise in signal.
Other causes for minor signal variations include extremes in temperature.
In the case of large signal variations (in a clean air environment), check for an installation
problem or the possibility of an interference gas being present.
Although the electrochemical sensors are very selective, there are some interference gases
which can also cause a response from the sensor. These gases are listed on the detailed
Specifications sheet pertaining to the sensor in use.
5.2 CALIBRATION
The transmitter is equipped with a remote calibration feature allowing one-man calibration at the
transmitter location. The transmitter output is measured using a plug-in type “Remote
Calibration Lead” (p/n 2900-01) designed to be adaptable to most multimeters. Zero and Span
adjustments are made at the transmitter. Recalibration is necessary when replacing the sensor.
Verification of calibration should be done at least once every 6 months for safety reasons and
for highly demanding applications, monthly verification is recommended.
Factory or on-site calibration services, customer training, and/or calibration kits can be provided.
Specify the sensor/transmitter type and gas when requesting any of the above.
Caution:
Only qualified personnel should perform the actual calibration. Users are advised to
consult the Armstrong Monitoring Corporation as to the recommended calibration gas
concentration for the application, and any other questions.
5.2.1 EQUIPMENT REQUIRED
• Digital multimeter
• “Remote Calibration Lead” provided with the transmitter
• “Trimmer Adjustment Tool” or miniature screwdriver
• Calibration kit (AMC-CK2800)
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