Model 5100-28-IT Combustible Gas Sensor Module
6.1 CALIBRATION FREQUENCY
The 5100-28-IT has been calibrated in the factory prior to shipment. It is recommended that the user check
calibration before placing in service. The IR sensor module must be calibrated annually. Periodic functional
tests are advisable for critical applications and hostile environments.
The sensor module microprocessor software includes high level self checking algorithms which provide
continuous sensor diagnostic and self adjustment. Users may elect to increase calibration periods based on
low drift experience during the first two calibration periods.
6.2 CALIBRATION PREPARATION
Calibration of the IR Sensor is accomplished by simple menu based steps and application of span gas.
If an error is made during any stage of the calibration process, hold the magnet stick at the key
M for 10 seconds. A scrolling display will indicate “Calibration aborted” and the sensor
module will exit the calibration activity and return to normal operating mode. The calibration
procedure can then be restarted
Calibration must be performed only when the area is known to be clear of combustible gas. If necessary, use
a portable instrument to confirm that there is no background combustible gas.
For compliance with Factory Mutual (FM) Apparatus, the Sierra Monitor Model 1200-26, 1250-01, 1256-01,
1260 -02 are the only FM Approved calibration gas delivery device. Use Model 5358-01 Calibration Adapter
or Model 5360-00 Gas Delivery Fitting.
6.3 CALIBRATION GAS DELIVERY METHODS
Calibration gas is can be delivered to the sensors via the following delivery devices:
Model 5358-01: Calibration Adapter - use with portable calibrators. See 6-1.
Model 5360-00: Calibration Gas Delivery fitting - permanently installed fitting which
allows tubing to be run to a convenient delivery location
6.4 CALIBRATION PROCEDURE
Table 6-1 shows the step by step process of the calibration procedure.
The procedures requires that the menu “keys” be activated using the magnet stick.
Each key press steps through the process of setting the zero value for clean air and
then setting the span value.
At each of these steps, apply calibration gas of the value corresponding to the setting
accepted on the sensor module display.
6.5 SENSOR EXPOSURE TO GAS
Calibration gas must be delivered to the sensor using the flow rate and duration listed in below:
Model Gas Flow Period
5100-28-IT Methane 300 cc/min Until Stable – 3 minute minimum
Following calibration, the IR module counts down for 300 seconds. During this time the module is updating its internal memory
and it is very important that its power not be interrupted
Figure 6 - 1: Model