Power Supply - Siemens SIMATIC LOGO! CMR2020 Operating Instructions Manual

Installation, connecting up, commissioning

4.1 Power supply

Overvoltage protection
NOTICE
Protection of the external power supply
If power is supplied to the module or station over longer power cables or networks, the
coupling in of strong electromagnetic pulses onto the power supply cables is possible. This
can be caused, for example by lightning strikes or switching of higher loads.
The connector of the external power supply is not protected from strong electromagnetic
pulses. To protect it, an external overvoltage protection module is necessary. The
requirements of EN 61000-4-5, surge immunity tests on power supply lines, are met only
when a suitable protective element is used. A suitable device is, for example, the Dehn
Blitzductor BVT AVD 24, article number 918 422 or a comparable protective element.
Manufacturer:
DEHN+SOEHNE GmbH+Co.KG Hans Dehn Str.1 Postfach 1640 D-92306 Neumarkt,
Germany
4.1 Power supply
Screw terminals for the power supply
①
②
③
Note
Power supply unit of the CMR is not electrically isolated
No electrical isolation means that the input and output circuits are not galvanically isolated.
26
L+ = live wire, positive pole of the DC voltage 12/24 VDC
M = negative pole/ground of the DC voltage 12/24 VDC
Functional ground
Serves to improve electromagnetic compatibility and to specify a common reference poten-
•
tial for all signals.
Is achieved efficiently by a connection to the DIN rail.
•
LOGO! CMR2020 / LOGO! CMR2040
Operating Instructions, 09/2014, C79000-G8976-C356-01