Net Safety Monitoring Inc.
STEP 5 — CALIBRATE
CALIBRATION PROCEDURE
WARNING: The calibration procedure requires about 5 minutes to complete. If gas is not applied at the appropriate time, a calibration failure may occur (refer to "Calibration Failure" on page 14 for specific information).
For accurate performance, the concentration of gas, corresponding to 0 to 25% oxygen is converted to a linear 4 to 20 mA output signal which can be powered from the primary dc supply of the instrument. Power up the unit for at least 4 hours BEFORE first calibration.
The following calibration procedure should be followed to ensure an accurate correlation between the 4 to 20 mA output signal and the gas concentration.
Calibration Procedure
1.Confirm successful power up of
2.Flow certified ZERO AIR at a rate of 0.5 litres per minute through the calibration cup for 1 minute to ensure clean air environment.
3.Use the Calibration Button or Reed Switch to access the Main Menu and wait for countdown to complete.
4. When Calibrate Sensor YES? displays, use the Calibration Button or Reed Switch to select YES? Selection will be confirmed by a flashing YES .
5.When Apply Clean Air displays apply clean air.
6.When Apply 20.9% O2 displays, apply O2 at a rate of 0.5 litres per minute using the calibration cup.
7.The display will show Calibrating as the internal settings are being modified (current loop 3.3 mA).
8.Remove span gas when the message Remove Gas displays (Status LED Green solid and 3.6 mA output).
9.The message Cal Complete will display when calibration is complete.
10.Apply zero gas (clean air) again to purge system.
Note: Always apply test gas after calibration to verify operation.
Figure 13: Calibration Procedure
Display | Calibrate | Apply Clean | Apply 20.9% |
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Shows | Sensor YES? | Air | O2 | Calibrating | Remove Gas | Cal Complete |
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Action | Select YES? | Apply clean | Apply O2 |
| Remove gas |
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| (zero air) |
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