YOKOGAWA EXA DO402G, Instruction Manual

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IM 12J6B3-E-H
6-2 Calibration
6-1-2. Diagnostic functions performed during calibration
The calibration is a semi-automatic calibration, which means that the sensor output is used for calculation of
sensor parameters after the readings have stabilized. The criteria for stabilization are set in service code 20.
If stable readings are not achieved within one hour error E1 message will appear on the display and the
procedure is aborted.
The calculated sensor parameters are compared with preset tolerances and if these conditions are not met,
Error E2 (Zero Error) or E3 (Slope Error) will be signalled.
NOTES:
1. Error messages that appear initially indicate inadequate settings of the diagnostic variables in service
codes 01, 20 and/or 22.
2. Patience improves the accuracy of calibration. When the EXA prompts the user that the preset criteria
are met by showing CAL.END message it only means that the minimum criteria are met. When
the signal still changes after this initial acceptance, EXA will automatically update the sensor
characteristics with the new information.
6-2. Calibration procedure using air calibration method
6-2-1. Preparation
Move the sensor to a maintenance site and wash off any dirt on the membrane. Lightly wipe off any
remaining water from the membrane with a soft tissue.
Expose the sensor to the air in an environment where there is no temperature change and no wind. ( A
convenient way to accomplish this environment is to place the sensor in an empty bucket)
NOTE:
If sensors are used without temperature compensating element, the temperature must be adjusted to
ambient temperature in service code 13.