Ph Operation - Extech Instruments 407227 User Manual

pH Operation

IMPORTANT NOTE: Manual or Automatic Temperature Compensation (covered earlier in
this manual) must be performed before proceeding with pH calibration and pH
measurements.
pH CALIBRATION
Note that the meter must be calibrated before each use
1. Press the POWER key to turn the meter on (if it isn't already on).
2. Connect the Combination pH electrode to the meter's BNC input socket and place the
electrode in a pH 7 buffer solution.
3. Turn the CAL pH7 potentiometer on the front panel until the display reads 7.00
4. Rinse the electrode with distilled water.
5. Place the electrode in the pH 4 or pH 10 buffer solution.
6. Turn the SLOPE pH potentiometer until the display reads 4.00 or 10.00.
7. Rinse the electrode in distilled water.
8. Repeat as necessary.
Note that if the adjustments described above do not yield a 4, 7, or 10 pH reading, as the
case may be, the electrode may require replacing.
pH MEASUREMENTS
1. Connect the combination pH electrode to the meter's BNC input socket.
2. Turn the meter on using the POWER key.
3. Place the electrode in the test solution and read the displayed pH value.
4. After measuring, rinse the electrode with distilled water.
ORP Operation (millivolts)
1. Connect the mV electrode (not supplied) to the BNC input jack at the top of the meter.
2. Turn the meter on using the POWER switch.
3. Select 'mV' (millivolts) via the meter's front panel slide-switch.
4. Place the electrode in the test solution and read the millivolt (ORP) value.
5. Rinse the electrode with distilled water before storing.
Note that calibration is not required for the ORP function.
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Page 4 Model 407227 Ver. 2.1 Oct. 2002
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