MODEL 54eA | SECTION 13.0 |
| CALIBRATION - pH |
13.5pH SLOPE ADJUSTMENT
1.If the electrode slope is known from other measurements, it can be entered directly into the controller. The slope must be entered as the slope at 25°C. To calculate the slope at 25°C from the slope at temperature t°C, use the equation:
298
slope at 25°C = (slope at t°C) t°C + 273
Changing the slope overrides the slope determined from the previous buffer calibration.
Adjust temperature Calibrate pH Output trim
ExitEnter
Buffer calibration Standardize pH pH slope
2.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.
3.Press the ê key three times to move the cursor to "Calibrate pH". Press Enter (F4).
4.Press the ê key twice to move the cursor to “pH slope.” Press Enter (F4).
ExitEnter
pH slope: 60.00 mV/pH
ExitEdit
5.Press Edit (F4). Use the arrow keys to change the slope to the desired value. The slope msut be between 45 and 60 mV/pH. Press Save (F4).
6.Press Exit (F1) four times to return to the main display.
NOTE
If Hold was activated during calibration, “Hold Mode Activated” will continue to flash in the main display. Return the sensor to normal and deactivate Hold. Refer to Section 5.6, step 11.
NOTE
During calibration, ERROR and WARNING messages may appear. If an ERROR message appears, press Exit (F1) to leave and return to the previous screen. If a WARNING message appears, press Cont (F3) to continue the calibration or press Abort (F1) to leave. Continuing the calibration after a warning message appears may cause substantial errors in the subsequent measurement. Refer to Section 16.9 for assis- tance.
79
