Xylem pHotoFlex/pHotoFlex Turb - Manual (Page 55)

pHotoFlex / pHotoFlex Turb Operation
55 ba75491d04 07/2006
4.6.5 Calibration
Why calibrate? pH electrodes age. This changes the asymmetry (zero point) and slope
of the pH electrode. As a result, an inexact measured value is dis-
played. Calibration determines the current values of the asymmetry
and slope of the electrode and stores them in the meter. Thus, you
should calibrate at regular intervals.
When to calibrate? ! After connecting another electrode
! When the sensor symbol flashes:
– after the calibration interval has expired
– after voltage interruption (e.g. empty batteries, empty
accumulator pack)
Buffer sets for
calibration
You can use the buffer sets quoted in the table for an automatic calibra-
tion. The pH values are valid for the specified temperature values. The
temperature dependence of the pH values is taken into account during
calibration.
Note
The buffers are selected in the Configuration / pH & ORP / Cal. type
menu, see section 4.6.4).
Buffer set Name on the
display pH values at
25 °C
Technical buffer solutions TEC 2.00
4.01
7.00
10.01
NIST/DIN buffer solutions NIST/DIN 1.679
4.006
6.865
9.180
12.454