Hach-Lange SI792 P, SI792x P, SI792x P-FF, SI792x P-PA User Manual - Manual (Page 72)

Calibration
70
Note: Calibrations must be performed by trained personnel. Incorrectly
set parameters may result in errors in sample measurements.
Note: To reduce the response time of the probes, briefly stir the buffer
solution with the probe and then hold it still.
8.1.1.1 Calibration with automatic buffer recognition
The buffer solutions selected in the configure menu ( section 5.2.3 on
page 40 ) must be used during calibration for accurate results. Other
buffer solutions, even those with the same nominal pH values, may
show a different temperature dependence and result in measurement
errors.
Complete the following steps to calibrate the pH probe:
1. Press CAL , enter passcode: 1100, ENTER . The display will show
CAL1.
2. Remove the pH and temperature probes from the process. Clean
the probes and immerse in the first buffer solution (any order).
Briefly stir the solution with the probes.
3. Press ENTER . Automatic recognition of the buffer solution will begin.
The display will first show the hourglass and no buffer value, then
the recognized buffer value followed by the measured millivolt
value. When the measurement is complete, the display will show
CAL2.
4. When CAL2 is displayed, remove the probes from the first buffer
solution and rinse thoroughly.
5. Complete a one-point calibration or start a two-point calibration:
• One-point calibration: press CAL to end the calibration. The
slope (%) and offset (mV) of the probe (based on 25 °C) will be
displayed.
• Two-point calibration: immerse the probes in the second buffer
solution. Press
ENTER . The buffer detection will repeat as for the