Siemens ESM

Interfaces, Displays and Operator Controls
Industrial Ethernet OSM/ESM
50
C79000-Z8976-C068-10
4.1.7 Signaling Contact/Terminal Block for Attaching the Power
Supply
The attachment of the power supply and the signaling contact is made using a 6-
pin plug-in terminal block with a screw locking mechanism.
L1 +
F1
M
M
F2
L2 +
+24V
+24V
Figure 24: Terminal Block for the Power Supply and Signaling Contact
!
Warning
Industrial Ethernet OSMs/ESMs are designed for operation with safety extra-
low voltage. This means that only safety extra-low voltages (SELV)
complying with IEC950/EN60950/ VDE0805 can be connected to the power
supply terminals and the signaling contact.
The power supply unit to supply the OSM/ESM must comply with NEC Class
2 (voltage range 18 - 32 V, current requirement 1 A)
The signaling contact can carry a load of maximum 100 mA (safety extra-low
voltage (SELV), DC 24V).
Exceptions:
• Supply by PELV (corresponding to VDE 0100-410) is also permitted if the
generated nominal voltage does not exceed the voltage limits 25 V a.c. or
60 V d.c.
• Supply by a SELV current source (corresponding to IEC 60950) or PELV
current source (corresponding to VDE 0100-410) power limitation is also
permitted as long as suitable fire protection measures are taken as
follows:
- Installation in a cubicle
- Installation in a suitable enclosure
- Installation in a suitably equipped room.