Knick PORTAVO 904X PH, User Manual

Page: 20 / 68

20
ISFET Calibration
– available if an ISFET sensor is connected
The calibration method is selected in the configuration menu.
Measurement
cal
CAL
ISFET‑ZERO Select the “ISFET‑ZERO” calibration mode to set
the operating point for the first sensor calibra‑
tion.
cal
“pH setpoint” blinks
Use  to set the buffer solution value.
Immerse the sensor in buffer solution.
cal
Calibration is performed. The ISFET operating point is displayed.
The meter then automatically returns to measuring mode.
Keep the sensor connected to the Portavo while performing the next calibration
step. The operating point will be taken into account for the following calibration.
When using ISFET sensors for pH measurement, the individual operating point of the
sensor first needs to be determined, and should be in the pH 6.5...pH 7.5 range. The
sensor is immersed in a buffer solution with a pH value of 7.00 for this purpose.
Note: The operating point only needs to be determined once for each ISFET sensor.
To abort calibration, you can press
meas
at any time.
Calibration