Siemens SIMATIC ET 200S Manual page 132

Wiring and Fitting
Components and protective measures
Various components and protective measures are prescribed when setting up an
entire plant. The types of component and the degree to which the protective
measures are binding depend on the DIN VDE regulation that applies to your plant
setup. The following table refers to Figure 5-1.
Compare ...
Circuit-breaking device
for PLC, sensors and
actuators
Short-circuit and overload
protection:
Grouped for sensors and
actuators
Load power supply for
AC load circuits with
more than five
electromagnetic devices
Safe electrical isolation
Safe electrical isolation must be provided for:
• Modules that must be operated at the following voltages: ≤60 VDC or ≤25
VAC
• 24 VDC operating current circuits
Setting up the ET 200S with ungrounded reference potential
From IM151-1 BASIC (6ES7 151-1CA00-0AB0), IM151-1 STANDARD
(6ES7 151-1AA02-0AB0), IM151-1 FO STANDARD (6ES7 151-1AB01-0AB0),
IM151-1 HIGH FEATURE (6ES7 151-1BA00-0AB0) and IM151-3 PN
(6ES7 151-3AA00-0AB0) the reference potential M connected to the nominal
supply voltage of the IM151-x at the rail (protective conductor) through an RC
combination and so allows an ungrounded layout.
To divert interference current, the reference potential of the IM151-1 is connected
internally to the rail (protective conductor) via an RC combination (R = 10 MΩ / C =
22 nF). High-frequency interference currents are thus discharged, and static
charge is prevented.
5-4
Refer to DIN VDE 0100
Figure 5-1
... Part 460:
¡
Main switch
... Part 725:
©
Single-pole
protection of
circuits
¢
Isolation by
©
transformer
recommended
¢
DIN VDE 0113
... Part 1:
Disconnector
... Part 1:
•
With grounded secondary
power circuit: single-pole
protection
•
Otherwise: all-pole
protection
Isolation by transformer
recommended
ET 200S Distributed I/O System
EWA-4NEB 780602402-12