Siemens SIMATIC ET 200M Operating Instructions Manual page 81

5.4.2 Wiring the Power Supply and IM 153-x
Power Cables
Use flexible cables to wire the power supply.
If you use only one cable per connection, you don't need an end ferrule.
Jumper
Use the jumper to wire the power supply module PS 307 with the IM 153-x. The jumper
comes with the power supply module.
Further 24 V connections
On the power supply PS 307 via the jumper an additional 24 V-connections are still free for
connecting the supply of the S7-300 modules.
Wiring the 24 V connections with redundant configuration with 2 x IM 153-2
Note
If, in a configuration for redundancy, you connect the supply voltage L+ when wiring to the
IM 153-2, this brings about a short circuit via the ground terminal.
Reason: The two IM 153-2 have a mutual ground cable via the BM IM /IM bus module.
with IM 153-2AA02 / -2AB01:
We recommend, with a redundant configuration, that you protect the L+-supply from the
IM 153-2 with 2.5 A.
with IM 153-2Bx00 / -2Bxx1:
• In configurations with ungrounded reference potential (jumper between M and functional
• With a configuration with grounded reference potential (bridge inserted between M and
ET 200M
Operating Instructions, 12/2008, EWA-4NEB780600602-08
ground removed, see the figure in the "Configuration of an ET 200M with ungrounded
reference potential (Page 54)" chapter), in the case of a polarity reversal an internal
electronic fuse is triggered and this regenerates after approx. 30 seconds.
functional earth) when connection this brings about a short circuit current via this bridge
and the functional earths.
In doing so, the IM 153-2 is not damaged if a protection is built in before the module
which is designed in accordance with the cross-section of the connection line.
5.4 Wiring the power supply and modules
Connecting
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