Siemens SIMATIC NET SCALANCE S615 - Power Supply

while the connection for protective earth is always low resistance, it is not necessarily low
impedance.
The resistance of a connection for protective earth must always be as small as possible to
divert fault currents safely to ground. The length of a protective earth cable can therefore
be several meters (m) long, without seriously impairing this e󹪜ect. For a functional ground
for diverting HF disturbances, this cable does however have impedance and is therefore not
suitable.
5.4 Digital input/output
The digital input and output are connected using a 2-pin plug-in terminal block in each case. Two
terminal blocks ship with the device.
CAUTION
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
present for at least 200ms.
Rules for wiring
• To wire the digital input/output, use a copper cable of category AWG18-16 or a cable with a
cross-section of 0.75 to 1.5 mm
2
.
• Always wire the digital input/output in pairs.
• The maximum permitted cable length is 30m.
Connecting up
5.4Digital input/output
SCALANCE S615
Operating Instructions, 05/2023, C79000-G8976-C389-08 51