Functional safety
13.5 Application examples
SINAMICS DCM DC Converter
714
Operating Instructions, 12/2018, A5E34763375A
13.5
Application examples
Note
Response time of the STO function
The STO safety function in the DC master is designed for a 250 ms response time.
The external redundant switch-off signal path via the contactor/circuit breaker must also be
designed for a 250 ms response time.
In six application examples (see the following figures), the safety functions STO and SS1 are
shown for applications with a safety relay and a contact block (line contactor and circuit
breaker) to safely shut down the armature circuit (first channel):
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STO application with line contactor
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STO application with circuit breaker
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SS1 application with line contactor
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SS1 application with circuit breaker
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SS1 application with line contactor and F-PLC
●
SS1 application with circuit breaker and F-PLC
Description of the applications
The SINAMICS DCM is activated and evaluated in all four application examples each with a
2-channel EMERGENCY STOP trigger mechanism (e.g. EMERGENCY STOP button, safety
door switch, etc.) via an additional 3SK1121 safety relay (green block).
●
STO application:
3SK1121-2AB40 safety relay
●
SS1 application:
Safety relay 3SK1121-2CB42 (with the option to set a delay time for quick stop)
Via the corresponding terminals of the safety relay, the STO input and the feedback circuit
RM1 / RM2 of SINAMICS DCM (red block, SAFETY circuit, second channel) are wired via
the contacts of the contact blocks (blue block, line contactor or circuit breaker, first channel).
●
For applications with line contactor, the feedback circuit is routed via contacts A1 and A2
of the line contactor KA1.
●
For applications with circuit breaker, the feedback circuit is routed via the undervoltage
coil U< of the circuit breaker 3WL.
In addition, E-STOP (terminals 106, 109, 110) and the 24V input P24 (terminal X177.9) of
the Power Interface are guided in SINAMICS DCM via the safety relay.
