ENMET ISA-44-RAL-OD - Manual (Page 17)

ISA-44RAL-OD / ISA-44RAH-OD ENMET Corporation
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6.0 Calibration 6.0 Calibration
6.1 Carbon Monoxide Detection Channel Calibration
The following procedure is for checking the calibration level and for recalibrating the Carbon Monoxide Channel of the
ISA-44RAL-OD. Refer to Figure 5 and Figure 2.
Perform A Complete Recalibration Periodically (at least monthly) and:
•
When you replace the sensor.
•
When the sensor encounters severe conditions (i.e., gross exposure to smoke or liquid hydrocarbon).
M ATERIALS
•
Cylinders of calibration gas of known CO concentration in air (i.e. 20 ppm and 50 ppm CO in air.).
D O N OT use CO in an inert carrier gas, such as nitrogen or argon.
•
Calibration gas fixture (with quick-disconnect fitting – ENMET part number 03605-001)
•
Small screwdriver (for potentiometer adjustment)
•
dc voltmeter
Figure 5: Test Gas Hook-up
P ROCEDURE
1. Turn operation switch to H ORN O FF . Be sure humidifier bottle is filled with tap water to Water Level mark.
2. Turn operation switch to P URGE O N . Measure purge voltage across TB-6(+) and TB2-7(-). It should be 1.6 Vdc +/-
.03 Vdc. If not 1.6 Vdc +/- .03 Vdc, adjust Purge Adjust Potentiometer (see Figure 2) until desired reading is shown.
Turn operation switch to H
ORN O FF and measure sensor heater voltage across TB2-6 and TB2-7. It should now read
0.86 Vdc +/- .03 Vdc. If it is not 0.86 Vdc +/- .03 Vdc, adjust Heater Adjust Potentiometer (see Figure 2) until
desired reading is shown.
3. Turn operation switch back to P URGE ON . Purge at least one hour, up to overnight.
R EMEMBER : If you suspect contaminated air in your compressor system, use clean bottled air to supply the sensors with a
continuous airflow.
4. After purging, turn operation switch to O PERATE . Allow 30 minutes to stabilize.
5. Remove the compressed air line and insert the calibration apparatus (see Figure 5).
ENMET
Test/Calibration
Gas
Calibration
Adapter
Pneumatic
Quick Release
Fittings