JUMO dTRANS pH 02, Operating Manual, Page: 51 / 136

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8 Calibrating a pH measurement chain
8.1 Notes
8.2 General information
The electrical properties of all sensors vary slightly from instance to instance
and also change during operation (due to deposits or wear, etc.). This causes
the output signal of the sensor to change.
The transmitter uses a typical, concentration-dependent characteristic to
measure ammonia with "normal" accuracy requirements. The individual
properties of the sensor are taken into account here by offsetting the zero
point. This considerably reduces the effort required for calibration.
The transmitter software is specially adapted for coolant monitoring.
8.2.1 Requirements
- The device must be supplied with voltage, see chapter 5 "Installation",
page 13 ff.
- A combination electrode must be connected to the transmitter.
- "PH STANDARD" must be configured as sensor in the basic setting.
- The device is in Measurement mode.
During calibration, relays and analog output signals adopt their configured
states!
When is calibration required?
- At regular intervals (depending on the sample medium and requirements).
- If negative values appear in the top display.
- If the top display indicates "Underrange/Overrange".
Every successfully completed calibration is documented in the calibration
logbook, see chapter 12 "Calibration logbook", page 88.
For a configuration example see chapter 7.2.1 "Measuring the pH value with
pH combination electrode", page 43.
A pH sensor can be connected to the optional board
- connected directly to the main input or
- connected to the "Analog input (universal)" optional board via a 2-wire
transmitter.