Stratos Multi E461N
125
7.2.8 Calibration Mode: ISFET Zero Point
Setting the ISFET Operating Point
When using Memosens 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.
Calibration Procedure
Calibration
[I] [II] … pH-ISFET
When you access calibration, the calibration values selected in the calibration presettings are used.
These settings can still be changed in the Calibration menu. If you do not want to perform calibration,
use the left
softkey
to go back one level and abort the calibration.
01.
Select the “ISFET Zero”
Calibration Mode
for setting the operating point for the first sensor
calibration and press
enter
to confirm.
02.
Press the
right softkey: Next
.
03.
Adjust the buffer value if necessary: Default pH 7.00
04.
Take the sensor out of the medium and rinse it well in deionized water.
CAUTION! Risk of electrostatic discharge.
Do not wipe the sensor or dab it dry.
05.
Immerse the sensor in buffer solution.
06.
Start calibration with the
right softkey: Next
.
✓
The ISFET operating point is calculated.
07.
Finally, confirm the ISFET operating point with the
right softkey: Adjust
.
A pH calibration, e.g., Calimatic 2-point calibration, can be performed afterward.
Note:
The operating point only needs to be determined once for each ISFET sensor.
7.2.9 Calibration Mode: Temperature
Adjustment of the Temperature Probe
This function is used to adjust the individual temperature probe tolerances or cable lengths for the
purpose of increasing the accuracy of the temperature measurement.
The adjustment requires an accurate measurement of the process temperature using a calibrated ref-
erence thermometer. The measurement error of the reference thermometer should be less than 0.1 K.
Adjustment without an accurate measurement may result in falsification of the displayed measured
value.
When using Memosens sensors, the adjustment value is saved in the sensor.
Calibration Procedure
Calibration
[I] [II] [Sensor]
01.
Select “Temperature”
Calibration Mode
and press
enter
to confirm.
02.
Enter the measured process temperature and press
enter
to confirm.
✓
The temperature offset is displayed.
03.
Adjust the temperature probe with the
right softkey: Save
.
The current adjustment and temperature offset data can be displayed in the Diagnostics menu:
Diagnostics
[I] [II] [Sensor]
Temp. Offset Log
