Endress+Hauser TopClean S CPC 30, Руководство по эксплуатации

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TopClean S CPC 30 4 Wiring
Hauser 23
4.3.7 Type of electrode connection, symmetrical /
unsymmetrical
!
Note!
The instrument is preset for symmetrical measurement (= with PML, potential matching
line). For unsymmetrical measurement, the setting must be changed accordingly (s.
page 34, Field A6, "Select connection type").
Fig. 19: Left: Symmetrical electrode connection
Right: Unsymmetrical electrode connection
ϑ ϑ
PA
PA PA
pH /
mV pH /
mV pH /
mV
IsFET IsFET
11
11 11
12 13 13 13 pH Ref. Ref. Ref.
PA
pH /
mV
11 12 13 pH Ref.
) ) ) )
A A A A
B B B B
) ) ) )
SRC SRC DRN DRN
IsFET CPS 401 IsFET CPS 401
ϑ ϑ
Glass electrodes Glass electrodes
C07-CPM153xx-00-06-08-en-003.EPS
symmetrical unsymmetrical
gn wt bn
gn wt ye bn
rd gn wt
bn
rd
gn wt ye bn
Symmetrical (with PML) Unsymmetrical (without PML)
"
Caution!
With a symmetrical connection, 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. also immersed in the buffer solution
during calibration.
If the instrument input is unsymmetrical, pH
measuring chains connected to assemblies can be
connected without an additional potential matching
pin. If necessary, connect the available potential
matching pin to terminal PE.
Benefit of symmetrical connection
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 (s. page 49) is possible with symmetric
ground measurement.
Disadvantage of unsymmetrical connection
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 (s. page 49) is
not
possible with
unsymmetrical measurement.
!
Note!
Do not connect the PML, otherwise there can be
shunt excitations.