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MLP-A/AR/AD-ST1400-25 13
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 poweredfrom
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 Controller—LED Green Blip/blink every 2 seconds; no fault indicated.
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
Select YES?
Display
Shows
Action
Calibrate
Sensor YES?
Apply clean
(zero air)
Apply Clean
Air
Apply 20.9%
O2
Apply O2
Calibrating
Remove Gas
Remove gas
Cal Complete