YSI pHotoFlex pH Handheld Colorimeter - Manual (Page 53)

pHotoFlex
®
pH Operation
53 ba76123e01 02/2013
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
rechargeable battery)
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.
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
YSI 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