Sierra Monitor Corporation 2-Wire Series User Manual
Model 4501-XX Toxic Gas Sensor Module
6. CALIBRATION
6.1 CALIBRATION FREQUENCY
The sensor module must be calibrated every 180 days. Periodic functional tests are advisable for critical
applications and hostile environments.
applications and hostile environments.
The sensor module microprocessor software includes high-level self checking algorithms which provide
continuous sensor diagnostic and self adjustment.
continuous sensor diagnostic and self adjustment.
6.2 CALIBRATION PREPARATION
Calibration of the sensor is accomplished by simple menu based steps and application of span gas.
N
OTE
If an error is made during any stage of the calibration process, hold the magnet stick at the
[M] for 10 seconds. A scrolling display will indicate “Operate Mode” and the sensor module
[M] for 10 seconds. A scrolling display will indicate “Operate Mode” 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 Hydrogen Sulfide gas. When in
doubt, use a portable instrument to confirm that there is no background Hydrogen Sulfide gas.
doubt, use a portable instrument to confirm that there is no background Hydrogen Sulfide gas.
For compliance with Factory Mutual (FM) Approvals, the Sierra Monitor Model 1250-01, 1260 -05 and 1260-45
are the FM Approved calibration gas delivery devices. Use the Model 5358-01 Calibration Adapter delivery
fitting.
are the FM Approved calibration gas delivery devices. Use the Model 5358-01 Calibration Adapter delivery
fitting.
Figure 6-1
Sample Gas In
Model 5358-01
Calibration Adapter
6.2.1 CALIBRATION GAS DELIVERY METHODS
Calibration gas can be delivered to the sensors via the Model 5358-01:
Calibration Adapter (Figure 6-1) - used with portable calibrators.
Calibration Adapter (Figure 6-1) - used with portable calibrators.
CALIBRATION PROCEDURE
The Calibration Menu is described on Table 6-1:
The procedure 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.
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.
the setting accepted on the sensor module display.
6.2.2 SENSOR EXPOSURE TO GAS
Calibration gas must be delivered to the sensor using the flow rate and
duration listed in below:
duration listed in below:
Model Gas
Flow
Period
4501-04
Carbon Monoxide 300 cc/min
Until Stable (minimum 3 minutes)
4501-05
Hydrogen Sulfide 300 cc/min
Until Stable (minimum 3 minutes)
4501-06
Chlorine
300 cc/min
Until Stable (minimum 3 minutes)
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