Procedure - Auto Calibration - Emerson Rosemount Analytical HART 5081-A-HT Instruction Manual

MODEL 5081-A
13.2 PROCEDURE — AUTO CALIBRATION
1. Verify that auto calibration has been enabled. See Section 7.10.
2. Obtain two buffer solutions. Ideally, the buffer pH values should bracket the range of pH values to be meas-
ured.
3. Remove the sensor from the process liquid. If the temperature of the process and buffer are appreciably dif-
ferent, place the sensor in a container of tap water at the buffer temperature. Do not start the calibration until
the sensor has reached the buffer temperature. Thirty minutes is usually adequate.
CALIBRATE
PH Cal
EXIT NEXT ENTER
CALIBRATE
AUtO CAL
EXIT NEXT ENTER
CALIBRATE
CAL bF1
EXIT NEXT ENTER
CALIBRATE
bf1
EXIT ENTER
CALIBRATE
bf1
4 . 01
EXIT ENTER
CALIBRATE
CAL bF2
EXIT NEXT ENTER
CALIBRATE
bF2
EXIT NEXT ENTER
CALIBRATE
bf2
10 . 00
EXIT ENTER
4. Press CAL on the remote controller.
5. Press NEXT until the PH CAL submenu appears. Press ENTER.
6. The AUtO CAL submenu appears. Press ENTER.
7. The CAL bF1 prompt appears. Rinse the sensor and place it in the first
buffer. Be sure the glass bulb and reference junction are completely
submerged. Swirl the sensor. The main display will show the pH of the
buffer based on the previous calibration. Press ENTER.
8. bF1 flashes until the pH reading meets the stability criteria programmed
in Section 7.10.
9. Once the reading is stable, the display changes to look like the figure
at left. The flashing number is the nominal pH, that is, the pH of the
buffer at 25°C. If the flashing number does not match the nominal pH,
press é or ê until the correct pH appears. Press ENTER to save.
10. The CAL bF2 prompt appears. Remove the sensor from the first buffer.
Rinse the sensor and place it in the second buffer. Be sure the glass
bulb and reference junction are completely submerged. Swirl the sen-
sor. The display will show the pH of the buffer based on the previous
calibration. Press ENTER.
11. bF2 flashes until the pH reading meets the stability criteria programmed
in Section 7.10.
12. Once the reading is stable, the display changes to look like the figure
at left. The flashing number is the nominal pH, that is, the pH of the
buffer at 25°C. If the flashing number does not match the nominal pH,
press é or ê until the correct pH appears. Press ENTER to save.
13. Press RESET to return to the main display.
SECTION 13.0
CALIBRATION - pH
69