Procedure
1. Press CAL on the IRC to enter the CALIBRATE menu.
The CALIBRATE sub-menu appears.
2. At the CALIBRATE sub-menu, press ENTER.
The CAL bF1 prompt appears.
3. Rinse the sensor and place it in the first buffer. Be sure the glass bulb and the
temperature element are completely submerged. Keep the sensor at least 3 in.
below the liquid level. Do not rest the sensor on the glass bulb. Dislodge any trapped
bubbles by swirling the sensor body.
4. Press ENTER.
BF1 flashes until the measured pH meets the programmed stability limits. If the pH
reading is not relatively stable after 20 minutes, the transmitter automatically leaves
the CALIBRATE menu and returns to the main display. If this occurs, consult
Chapter 8 for assistance. Once the reading is stable, the display moves forward by
showing a flashing number with the nominal pH.
5. Change the value by using the up and down arrows until the correct pH of the buffer
solution appears. Press ENTER to save the first calibration point.
CAL BF2 appears.
6. Remove the sensor from the first buffer.
7. Rinse the sensor and place it in the second buffer solution. Again, make sure the
bulb is completely submerged and the bubbles are dislodged by swirling the sensor
body.
8. Press ENTER.
BF2 flashes until the reading is stable.
9. Repeat steps 4 and 5.
The calibration is now complete, but the transmitter remains in the CALIBRATE sub-
menu for two minutes after you press ENTER.
10. Remove the sensor from the buffer and reinstall it into the process stream. If the
HOLD feature was used, be sure to turn off HOLD.
The sensor will not calibrate if the electrode slope (calculated by the transmitter
during calibration) is unacceptable. The transmitter displays a SLOPE ERR HI or
SLOPE ERR LO error message. Refer to the Chapter 8 for assistance.
NOTICE
The electrode slope can be displayed by pressing CAL on the IRC. The CALIBRATE sub-
menu appears. Press NEXT. The STD sub-menu appears. Press ENTER. The STD prompt
appears. Press ENTER again, and the slope appears on the display. For a good sensor, the
slope is generally 50 to 60 mV.
Measurements
42 Rosemount 5081
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