Table of Contents
Advertisement
Chapter 2
Setting Up
Filtering
The
pop-up menu gives the choice of
Low pass
low-pass filters. This filter removes high frequency noise. pH and ion
selective electrodes have a slow response time, usually in the seconds,
and the
10 Hz
filter setting should be used with these electrodes.
Inverting the Signal
The
checkbox changes the polarity, to invert displayed signals.
Invert
Units
Click
to display the Units Conversion dialog. However, when
Units...
using LabChart to record data from pH and ion selective electrodes:
with single or double point calibration, use the pH Extension, and for
multiple point calibration (more than two points), use the Multipoint
Calibration extension; do NOT use Units Conversion. Both extensions
are available from the ADInstruments website. For more information
about Units Conversion, see the LabChart Help Center.
Calibrating the pH Amp Electrode
Calibration of the pH electrode should be performed using the pH
Extension. The pH Extension is a LabChart software plug-in that:
•
performs single or double point calibration of the pH or ion
selective electrode;
•
prepares a calibration graph from the measured electrode signal;
•
enables manual temperature compensation (MTC) adjustment; or
•
enables automatic temperature compensation (ATC) if
temperature readings are collected on a second channel.
The resulting calibration information is used to convert the raw
voltage signal from the electrode into appropriate units (e.g. pH, pF,
pNa), which will then be displayed for that input channel. The pH
Extension adds the
pH Calibration...
command to the LabChart Channel Function pop-up menu.
Multiple point (more than two points) linear or non-linear calibration
can be performed with the Multipoint Calibration Extension.
Full details on using the pH Extension can be found in the
pH Extension User's Guide, which is installed with the software.
,
2 kHz
50 Hz
(Windows) or
(Macintosh)
pH...
and
10 Hz
23
Advertisement
Table of Contents
