Hach-Lange SI792 D, SI792x D, SI792x D-FF, SI792x D-PA User Manual - Manual (Page 77)

Calibration
75
2. Remove the sensor from the process and place in air or other
(gaseous) calibration medium.
3. Enter the actual relative humidity and press ENTER . The display will
show the entered (or default) barometric pressure.
4. Enter the barometric pressure and press ENTER . A drift check will
begin. The drift check may take some time. When complete, the
display will show the new slope and zero (relative to 25 °C and
1.013 mbar).
Note: To exit the drift check after > 10 seconds, press
CAL
(accuracy will be reduced).
5. Press ENTER to end the calibration. Return the sensor to the
process. The measured value will be shown in the display
alternately with Hold.
6. Press ENTER to return to the measure mode.
8.1.4 Calibration by comparison
The sensor can be calibrated for DO (or gas volume concentration) by
entering the sample value from a measurement in an instrument such
as a laboratory or portable meter. The sensor does not need to be
removed from the process during calibration. The sample temperature
should correspond to the measured process temperature for accurate
results.
1. Press
CAL , enter passcode: 1105, ENTER . The display will briefly
show CAL PRD and then StorE.
2. Collect a grab sample for measurement in the lab. Press ENTER to
store the sample value in the transmitter.
The cal mode indicator will flash to indicate that calibration is not
complete. The transmitter will continue to measure and display the
current sample values.
3. Measure the grab sample with a laboratory or portable meter.