Liquisys M CPM223/253
Commissioning
Hauser
71
6
Commissioning
6.1
Things to note when commissioning digital sensors
pH sensors with Memosens functionality save the calibration data. For this reason, commissioning
these sensors is different to commissioning standard electrodes.
Proceed as follows:
1.
Install the transmitter and the assembly.
2.
Connect the transmitter and the sensor cable.
3.
Configure the transmitter for your specific requirements (see "System configuration" section).
4.
Connect the sensor with the Memosens functionality, which was precalibrated at the factory,
and immerse it into the medium or the buffer.
5.
The saved sensor-specific calibration data are automatically transmitted to the transmitter.
6.
The measured value is displayed.
Normally, you can accept this value without calibrating the sensor. A calibration is only
necessary if particularly high demands are made on the accuracy.
7.
Check the measured value transfer to the process control system or the signal processing unit.
6.2
Things to note when commissioning ISFET sensors
Switch-on behaviour
A control circuit is created when the measuring system is switched on. During this time (approx.
5 ... 8 minutes), the measured value adjusts to the real value. This settling behaviour occurs every
time the liquid film between the pH-sensitive semi-conductor and the reference lead is interrupted
(e.g. caused by dry storage or intensive cleaning with compressed air). The settling time depends on
the length of the interruption.
Sensitivity to light
Like all semi-conductor elements, the ISFET chip is sensitive to light (measured value fluctuations).
However, this only affects the measured value if the sensor is directly exposed to sunlight. For this
reason, avoid direct sunlight when calibrating. Normal ambient light does not have any effect on
the measurement.
6.3
Function check
#
Warning!
• Check all connections for correctness.
• Make sure that the supply voltage is identical to the voltage written on the nameplate!
