TM 09241 B-12&P
2-11. OPERATION OF pH/TEMPERATURE TEST SET. - continued
Calibration procedures. See figure 2-12.
A one or two buffer calibration should be performed before pH is measured. It is recommended that a two
buffer calibration using buffers that bracket the expected sample range be performed at the beginning of
each day to determine the slope of the electrode. This serves the dual purpose of determining if the
electrode is working properly and storing the slope value in memory. Perform a one buffer calibration every
two hours during operation/testing to compensate for electrode drift.
There are two ways of calibrating the pH/temperature meter; auto calibration which recognizes the buffers
7.00, 4.00, and 10.00 included in the kit or manual calibration for use with buffers other than 7.00, 4.00,
and 10.00. The following procedures cover each method.
Table 2-4 lists and describes error codes that may be displayed during calibration and measurement.
If the meter does not function per the following procedures, see troubleshooting.
(1) Auto calibration with two buffers.
Loosen cap on storage/soaker bottle (14) and slide bottle off electrode (11). Save for reuse.
If an air bubble is in electrode (11) tip, shake as you would a clinical thermometer to remove.
Rinse two beakers (15) three times with demineralized or distilled water.
Choose either 4.00 (16) and 7.00 (17) or 7.00 and 10.00 (18) buffers, whichever will bracket your expected
sample pH range.
Open one each buffer capsule (19) and dissolve powder in beaker (15) with 3.4 oz (100 ml) demineralized or
distilled water. Use two stir rods (20), one for each, if needed.
Rinse electrode (11) and probe (12) tip in demineralized or distilled water. Shake dry and place into lowest
prepared buffer solution.
Press power keypad (2) to turn meter on.
While stirring gently, press cal keypad (4), CALIBRATE is displayed above the main readout and P1 is
displayed in the lower field. P1 indicates that the meter is ready for the first buffer. When the electrode (11) is stable the
ready prompt will be displayed and the temperature corrected pH value for the buffer is displayed. Press yes keypad (1).
The display will remain frozen for two seconds then P2 will be displayed in the lower field indicating the meter is ready for
the second buffer. Remove electrode and probe (12).