Xylem HandyLab 680 - Manual (Page 43)

HandyLab 680 Operation
43 ba77041e01 03/2014
4.7.4 pH calibration
Why calibrate? During the operation of an IDS pH sensor, the zero point (asymmetry)
and slope of the sensor change with time.As a result, an inexact mea-
sured value is displayed. Calibration determines the current values of
the zero point and slope of the pH sensor and stores them in the mea-
suring instrument.
Thus, you should calibrate at regular intervals.
When do you have to
calibrate?
 When the calibration interval has expired
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 consideration
during the calibration.
Alternative temperature on
off Takes the measured temperature value from
an IDS sensor.
This menu item is only available if an IDS
sonsor without temperature sensor and an
IDS sensor with temperature sensor are
connected.
pH resolution 0.001
0.01
0.1 Resolution of the pH display
mV resolution 0.1
1 Resolution of the mV display
Reset - Resets all sensor settings to the delivery
condition (see section 4.14.1)
Menu item Possible setting Description