Endress+Hauser Topclean S CPC30, Руководство по эксплуатации

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4 Wiring and pneumatic connection of Topclean S Topclean S
20 Hauser
4.1.3 Analogue pH glass electrodes and ISFET sensors
Cable types
You require a screened special cable to connect analogue pH/redox electrodes and ISFET sensors.
You can use the following multicore and preterminated cable types:
• CPK1 for electrodes with standard plug-in head GSA and without Pt 100
• CPK9 for electrodes with TOP 68 plug-in heads (ESA / ESS) and Pt 100
• CPK12 for ISFET pH sensors and pH/redox glass electrodes with TOP 68 plug-in heads (ESB) and
Pt 100 / Pt 1000
Electrode connection with PML (symmetrical) or without PML (unsymmetrical)
You can connect the sensor with PML (symmetrically) or without PML (unsymmetrically), note the
following differences
!
Note!
The instrument is preset for measurement with PML (potential matching line). For measurement
without PML, the setting must be changed accordingly (see page 56, "Select connection type").
With PML (symmetrical) Without PML (unsymmetrical)
"
Caution!
With a connection with PML, the line to the
potential matching pin (PML) must be
connected to the potential matching terminal
of the instrument. The PML must
always be in
contact with the medium, i.e. immersed in the
buffer solution during calibration.
If the instrument input is without PML, pH
measuring chains connected to assemblies can
be connected without an additional potential
matching pin. If necessary, connect the brown
wire to terminal PE.
Benefits of connection with PML
Measurement is easier under difficult ambient
conditions (e.g. strongly flowing or high-
impedance media or partially soiled
diaphragm).
Monitoring of the reference electrode by the
SC system (see page 73) is possible.
Disadvantages of connection without
PML
The measuring chain reference system has a
heavier load, meaning that measuring errors in
limiting operating conditions are possible (see
symmetrically high-resistance instrument
input).
Monitoring of the reference electrode by the
SC system (see page 73) is
not possible.
!
Note!
Do not connect the PML, otherwise there can
be shunt excitations.