Specifications

3. Operation MI 611-211 – October 2005
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Measurement (normal) mode. If you enter the correct passcode, the display will read
CAL MANUAL. If you need to adjust the temperature per the note above, go to CAL TEMP in
the structure and enter the correct value. Then go back to either CAL MANUAL or to
CAL AUTO.
If you are measuring ORP, instead of a MANUAL SINGLEPT calibration, you can use a
MANUAL ABSOLUTE calibration. This is an internal calibration that rids the transmitter of
nonapplicable calibration data. To do this, go from MANUAL ABSOLUTE to
PERFORM ABSOLUTE and press ENTER.
If your diagnostics were configured to enable a COAT message, this message appears if the sensor
is out of the solution for a sufficient period of time. This is a normal occurrence. The message
disappears when you immerse your sensor.
NOTE
Accurate calibration requires that the sensor and the standard solution must be
stable at the same temperature. A less than optimum calibration results if either the
sensor or the solution is changing temperature during the calibration procedure. For
example, when a sensor is removed from a hot process, the sensor takes several
minutes to cool to ambient temperature. Calibration should not be performed until
the sensor has reached a stable temperature. You can monitor the temperature of the
sensor in Status mode.
Manual Calibration
To perform a manual calibration (grab calibration):
1. Specify SINGLEPT or TWO PT calibration. SINGLEPT must be used for ORP.
2. Immerse your sensor in Solution 1 and press ENTER. If stability parameters were
configured ON, the display READING XXXXXXXX will flash until stability is
achieved and then alternate with the message ENTER TO EDIT. Wait for this message
and then press ENTER again. If stability parameters were configured OFF, watch for
the measurement to stabilize before proceeding to press ENTER.
3. If the reading is not correct, edit it to the correct value under VALUE 1. Press ENTER.
Wait for a display of CAL COMPLETE (for SINGLEPT) or IMMERSE IN SOL 2
(for
TWO PT). If calibration was not successfully completed, the display will read
CAL ERROR and return you to MANUAL SINGLEPT or MANUAL TWO PT.
4. If you are doing a 2-point calibration, place the sensor in the second solution and
repeat the procedure. Upon completion a display of CAL COMPLETE will appear.
5. Press MEASURE to return to Measurement mode.
NOTE
A manual calibration of the transmitter without its sensor can also be done with
theoretical millivolt inputs. See “Electronic Calibration” below.
Automatic Calibration
In Automatic Calibration, the pH value is first measured with the last calibration constants
entered to decide which buffer is in use. The algorithm checks each buffer starting with Buffer 1