Brochure/Catalogue

Installation advice for instrumentation and control engineering
Surge protection for binary signals
The VSPC 4 SL plug-in surge protector can be used to
protect the 24-V supply and also the 24-V switching signals.
The unprotected side points in the direction where the pulse
or interference is expected. The connecting cable’s shield
is connected to terminal 3 e. g. the Weidmüller clamping
bracket (KLBÜ) can be used.
PLC
PE
PROTECTED
UNPROTECTED
8
10
12
2
4
6
1
3
5
7
9
11
VSPC 4S L
24 V DC
8924320000
U:28 V DC
C
I:0,3 A
N
C1 <1 kA 8/20
IP 20
U50 V
P
≤
2
1
34
GND
The earthed DIN rail can then pick up the pulse and
discharge it to the earth.
For long cables, and especially for current loops, additional
protection is set-up at the sensors. The VSPC BASE FG
oating-earth base can be used there. A built-in gas
discharge tube makes this a “high impedance” earth, which
prevents an interference current on the shield.
B
B.1252028840000
Lightning and surge protection for control and instrumentation signals