Calibration (cont)
In Line Calibration
The in line calibration procedure can be used to calibrate the sensor directly in line, against a liquid sample with a known dissolved oxygen concentration.
To perform this type of calibration, the instrument must be set for calibration In line. Switch on the instrument, if necessary, and wait a minute or so for the displayed measurement to settle.
Expose the sensor to a liquid sample with a known gas concentration.
Press the CAL button. Remember, this button may have been locked out to prevent an accidental reset.
A brief clearing
Assuming you know the gas content to be a certain value, you can adjust the displayed value with the × Ø keys.
When the reading is adjusted to the known concentration, press CAL again. The instrument displays CAL and returns to the measurement mode.
In Air Calibration (oxygen sensors only)
The oxygen sensor can be accurately calibrated in air. To perform this type of calibration, the instrument must be set for calibration In air.
You can perform this procedure with the sensor connected to the instrument, but without the flow chamber mounted.
The membrane must be dry, and prior to calibrating it may be necessary to remove the
Switch on the instrument, if necessary, and wait a minute or so for the displayed measurement to settle.
The process is then exactly the same as for calibration in a span gas, detailed previously.
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