User Manual

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Siemens PXC-NRUF – Automation station, compact series CM2N9760en_07
Building Technologies 2015-12-23
Connect field devices
This is a device using the 4-wire principle. System ground (G0) and measuring
ground (– or GND) are electrically isolated.
For active field devices using 4-wire technology, this connection is in the field
device.
For active field devices using 3-wire technology, the connection must be established
separately:
−  Either at the terminal on the field device.
−  Or in existing plants, using only 3 wires: at the automation station between
one of the terminals (–) and G0.
A) Field device supply of system transformer
Compulsory
specification for
transformer
Type
Safety isolating transformer AC 230 V/AC 24 V to EN 61 558
Fusing AC 24 V
Max. 10A slow-blow (Extra-low voltage fuse)
Max. 13 A circuit breaker
Counter inputs Counter inputs must be shielded, if they count faster than 1 Hz and are laid with
more than 10 meters using analog inputs in the same cable duct.
Passive sensor
(e.g. QAM... , Ni 1000)
Active sensor
(e.g. QFM... , humidity)
PXC NRUF
9760A03
AC 24 VG
G0
G0
G0G0GGG
24V
UO UO
UI UI
CP+ CP-
GND
+15
QAM...
(Ni1000)
QFM...
(r.h.)
M
G
B
M
B
M
Magnetic valves
(e.g. M3P... + ZM
or MX...461...).
PXC NRUF
9760A04
M3P... + ZM
AC 24 V
G
G0
G0G0G0
GGG
2
1
4
3
N
24V
UO UO
UI
UI
CP+ CP-
MX...461...
1
2
3
G0 (GN)
G (GL)
YM
Y
4
GND
+15
STOP
Note!