triOS TpH - Calibration; pH Calibration Procedure

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D01-068en201913 Manual TpH
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Calibration Use
TpH // Calibration
5 Calibration
TpH sensors that have not been used for a long time or that are new should be calibrated before measurement. Calibration
should then be repeated at regular intervals. The calibration intervals depend on the type of application. Checks with standard
solutions are recommended to determine the intervals. TriOS oers suitably bottled buer solutions pH4 and pH7 (see chapter
8).
Calibration is possible both on the controllers (see chapter 8) and via Modbus. The calibrations performed are stored internally
by the sensor. Thus, the current calibration is always present.
5.1 pH Calibration
With the calibration, the zero value (pH7) and the scaling factor (pH4) are calibrated. For calibration, select pH buer solutions
with an accuracy of +/- 0.01pH and observe the temperature. Fresh or newly prepared solutions must be used for each calibra-
tion! TriOS oers an ideal set for the TpH calibration with a sensor holder and buer solutions for 6 calibrations.
Do not wipe the electrode.
NOTICE
Procedure:
• Since the pH value is temperature-dependent, it is recommended to check the temperature with a reference
thermometer before the rst pH calibration.
• If the temperature measured by the sensor deviates more than 1°C from the one measured by the reference
thermometer, a calibration of the temperature oset is necessary.
• Rinse the sensor with distilled water.
• Immerse the TpH in pH7 buer solution, the sensor head (black) should be immersed as completely as possible
(the picture on the next page shows the immersion depth in the beaker with the buer solution as a red line).
Otherwise, measurement uctuations may occur.
Buer Solution pH7
6 x 25 ml
Buer Solution pH4
6 x 25 ml
Do not stir the sensor in the buer solution
NOTICE