Model PH220 Version 3.1 11/2005
5
Measuring pH
Electrodes should always be rinsed before and between samples
with distilled or DI (de-ionized) water to remove all traces of
storage solution, process media, or previous test solution.
1.
Connect the pH electrode to the meter.
2.
Turn the meter on using the on/off button . Wait for the self test (‘SLF tSt’) to
finish.
3. Use
the
MODE
button to select pH mode. The unit of measure appears on the LCD.
4.
To change the unit of measure for temperature (
o
C to
o
F or
o
F to
o
C), press and hold
the
MODE
button for 3 seconds. The LCD reflects the current unit of measure.
5.
Rinse the electrode with distilled or deionized water.
6.
Place the electrode in the solution. Allow 30 seconds for the electrode/ATC to reach
thermal equilibrium with the buffer solution.
7.
After the measurement stabilizes, view the pH reading on the main display. An out of
range reading is indicated by the display icon ‘HHH’. Note that ‘HHH’ will also display
when the electrode is disconnected from the meter.
8.
When the test is complete rinse the electrode with distilled or deionized water.
Measuring ORP (millivolts mV)
1.
Connect the ORP electrode to the meter.
2.
Rinse the ORP electrode
3.
Turn the meter on using the on/off button . Wait for the self test (‘SLF tSt’) to finish.
4. Use
the
MODE
button to select mV mode. The display will reflect the unit of measure.
5.
Place the electrode into a sample solution. When the LCD stabilizes it will read the
redox potential of the sample in millivolts (mV).
6.
When the test is complete rinse the electrode with distilled or deionized water.
Automatic Temperature Compensation (ATC)
The millivolt output of a pH electrode varies with temperature, and for this reason the meter
must compensate for these variations to obtain accurate measurements. The PH220
automatically compensates for solution temperature changes with the electrode’s built-in
thermometer. The temperature compensation is active when the solution temperature
deviates from room temperature. The temperature of a solution is displayed on the lower
LCD line of the instrument.
Automatic Power OFF
To conserve battery power, the instrument automatically shuts off after 10 minutes of
inactivity. To disable or enable this feature, follow the steps below:
•
To disable: With the power on, press and hold the on/off button for 2 seconds
(oFF and AtP will display). The Auto Power OFF feature is now disabled.
•
To enable: With the power on, press and hold the on/off button for 2 seconds (on
and AtP will display). The Auto Power OFF feature is now enabled.
•
Each time the meter is turned off the Auto power OFF feature is set to the enabled
mode.
