Wiring the FM 351
4-8
FM 351 Positioning Module
C79000-G7076-C351-02
!
Caution
Interlock the power network contactors.
Interlocking of the contactors is shown in Figure 4-3.
If you do not keep to this rule, a short circuit can occur in the main power network.
Note
Direct connection of inductive components (for example relays and contactors) is
possible without external wiring.
If SIMATIC output power circuits can be turned off by additionally installed
contacts (for example relay contacts), you must include additional surge protection
with inductive components (an example of surge protection is shown below).
Example of Surge Protection
Figure 4-4 illustrates an output circuit that requires additional surge voltage
protection. Diodes or Z diodes are used with coils activated by direct current.
with diode
with Z diode
–
–
+
+
Digital output of the FM 351
e.g. 1Q0
Contact in output circuit
Digital output of the FM 351
e.g. 1Q0
Figure 4-4 Relay in the Output Circuit
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