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4 Operation
4.3
Calibrating pH transmitters and checking connected components
4.3.1
Transmitter settings
Depending on the device configuration (manual temperature specification or automatic temperature
compensation), you first have to set the reference conditions for the temperature compensation on the
transmitter.
In the case of a manual temperature specification, you have to set the temperature to 25 °C.
In the case of automatic temperature compensation, the temperature of the connected temperature
probe must be adjusted to 25 °C. If this is not possible, an alternative solution is to connect a resistor of
110 Ω (Pt100) or 1.1 kΩ (Pt1000).
4.3.2
Settings and steps for operating the simulator
Example for the measuring range 2 to 12 pH≙ 0 to 20 mA current output
1. Test the battery of the pH simulator and visually in-
spect the connecting cable (coaxial cable).
2. Connect the simulator to the transmitter using the cor-
rect coaxial cable.
3. Switch on the simulator.
4. Set the simulator's output resistance to "1000 MΩ" (1).
5. Turn the pH selection switch to "7".
6. Using the zero point adjustment, set the display of the
transmitter to 7.00 pH ±0.02 pH.
The value of the current output on the transmitter must
be 10 mA ±1 % (test using a measuring device).
7. Turn the pH selection switch to "2" or "12" (2).
8. Using the transmitter's slope adjustment, set the dis-
play of the transmitter to pH value 2.00 pH ±0.02 pH or
12.00 pH ±0.02 pH.
9. Check the zero point 7 pH again.
10. Check the linearity of the current output by turning the
pH selection switch from "2" (≙ 0 mA) to "12" (≙
20 mA). You can find the correct current values in the
diagram on the next page.
11. Switch off the pH simulator (3).
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