Digital Input/Output - Siemens SIMATIC NET SCALANCE MUM856-1 Operating Instructions Manual

Connecting up

5.6 Digital input/output

Protective earth/functional ground
The connection of the reference potential surface with the protective earth system is
normally in the cabinet close to the power feed-in. This earth conducts fault currents to
ground safely and according to DIN/VDE 0100 is a protective earth to protect people, animals
and property from too high contact voltages.
Apart from the protective earth, there is functional grounding in the cabinet. According to
EN60204-1 (DIN/VDE 0113 T1) electrical circuits must be grounded. The chassis (0 V) is
grounded at one defined point. Here, once again the grounding is implemented with the
lowest leakage resistance to ground in the vicinity of the power feed-in.
With automation components, functional ground also ensures interference-free operation of
a controller. Via the functional ground, interference currents coupled in via the connecting
cables are discharged to ground.
Connecting up functional ground
Follow the steps below to connect the functional ground:
1. Put the grounding terminal ①, and the screw ② together as shown in the drawing.
①
②
2. Screw in the screw ② with a maximum tightening torque of 1.5 Nm.
5.6 Digital input/output
The device features a digital input and output (M12 A-coded).
Damage due to voltage being too high or too low
The voltage at the digital input/output must not exceed 30 VDC and not fall below -30 VDC,
otherwise the digital input/output will be destroyed.
Note
Interference pulse
To avoid evaluating an interference pulse, the pulse for the signal 1 (TRUE / HIGH) must be at
least 200 ms.
52
Grounding terminal with cable
Screw (M4 thread) with spring washer and washer
CAUTION
Operating Instructions, 08/2021, C79000-G8976-C628-02
SCALANCE MUM856-1