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1. Be sure the pH feature has been enabled. See Section 5.8.
2. The controller comes from the factory set for automatic pH calibration. To do a manual calibration, the factory
default setting must be changed. Refer to Section 5.8.
3. Obtain two buffer solutions. Ideally the buffer pH values should bracket the range of pH values to be meas-
ured. Also obtain a thermometer. The pH of most buffer solutions is a function of temperature. To calibrate the
sensor properly, the pH of the buffer at the measurement temperature must be entered in the analyzer.
4. Remove the sensor from the process liquid. If the process and buffer temperatures are appreciably different,
place the sensor in a container of tap water at the buffer temperature. Do not start the calibration until the sen-
sor has reached the buffer temperature. Thirty minutes is usually adequate.
12.3 MANUAL TWO-POINT CALIBRATION
MODEL 54eA SECTION 12.0
CALIBRATION - pH
5. From the main display, press any key to obtain the main menu. With
the cursor on "Calibrate" press Enter (F4).
NOTE
If Hold was enabled in Section 5.6, the hold screen will appear.
To activate hold, refer to Section 5.6, step 11.
6. Press the arrow key three times to move the cursor to "Calibrate
pH". Press Enter (F4).
7. With the cursor on "2-pt calibration" press Enter (F4).
8. Rinse the sensor and thermometer with water and place them in
buffer 1. Be sure the glass bulb and junction are completely sub-
merged. Swirl the sensor. Press Cont (F3). "Wait" flashes until the
reading stabilizes. The large number on the first line is the measured
pH based on the previous calibration.
If the controller appears locked, the reading is not stable enough.
Investigate and correct the cause of the noise or drift (see Section
14.8). Alternatively, change the stability limits (see Section 5.8) and
repeat the calibration.
9. The screen at left appears once the reading is stable. Press Edit (F4)
and use the arrow keys to change the reading to the pH of the buffer
at the measured temperature. Most commercial buffers have a table
of pH values as a function of temperature on the label. Press Save
(F4) to store the value. If the pH value on the first line is correct, press
Pt 2 (F3) and go to step 11.
Adjust temperature
Calibrate pH
Output trim
Exit Enter
2-pt calibration
Standardize pH
pH slope
Exit Enter
4.01 pH
Pt. 1 : 04.00pH 25°C
Exit Pt 2 Edit
4.01 pH
Calibrate point 1
Abort Cont