Temperature Compensation - Extech Instruments 407227 User Manual

Temperature Compensation

For accurate pH measurements and calibration, the temperature of the solution under test
must be known. This can be accomplished manually or automatically. Read through the steps
for each (below) and determine that best method for the application at hand:
Automatic Temperature Compensation
NOTE: For Automatic Compensation, the supplied thermometer must be used. Perform
these steps before each use or when the temperature of the solution under test changes.
The thermometer can remain in the solution while taking pH measurements in order to
track temperature changes and compensate for them if necessary.
1. Select 'pH ATC' on the meter's front panel slide-switch.
2. Plug the supplied thermometer into the meter's temperature sensor input jack.
3. Place the other end of the thermometer into the solution under test.
4. Perform a pH Calibration or take a pH measurement as described later in the manual.
Manual Temperature Compensation
NOTE: For Manual Compensation, an external thermometer is required (separate from the
one supplied with the meter). Perform these steps before each use or when the
temperature of the solution under test changes
1. Place a thermometer in the solution under test and note the reading.
2. Select 'pH MTC' on the meter's front panel slide-switch.
3. Press the "MTC" key and 25.0
Using the ">>" key (for 1
temperature. Continue editing until the displayed temperature equals the measured
temperature that was noted earlier.
4. Perform pH calibration or pH measurement normally.
Calibrating a new thermometer
1. Connect the thermometer to the meter's temperature sensor input jack.
2. Select "pH ATC" via the meter's front panel slide-switch.
3. Place the temperature probe and a mercury thermometer in water.
4. Adjust VR6 (inside the battery compartment, see diagram below) until the displayed
value matches the mercury thermometer reading.
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o
C will display on the LCD temperature display line.
o
C steps) and the ">" key (for 0.1
Inside battery compartment
VR6
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o
C steps), edit the displayed
Model 407227 Ver. 2.1 Oct. 2002
1.877.766.5412
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