Calibration - wtw pHotoFlex pH Operating Manual

Operation
Why calibrate?
When to calibrate?
Buffer sets for

calibration

54
4.6.5 Calibration
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.
 After connecting another electrode
 When the sensor symbol flashes:
– after the calibration interval has expired
– after voltage interruption (e.g. empty batteries, empty
rechargeable battery)
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.
Buffer set
WTW technical buffer solutions
NIST/DIN buffer solutions
The buffers are selected in the Configuration / pH & ORP / Cal. type
menu, see section 4.6.4).
pHotoFlex
Name on the pH values at
display 25 °C
TEC 2.00
4.01
7.00
10.01
NIST/DIN 1.679
4.006
6.865
9.180
12.454
ba75975e05
®
pH
10/2017