Fig. 16 Interface Classification - Interface Type D - Pilz Intern PMC SR6 Manual

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Interface type D
+
TA high-side
TA low-side
GND
Fig. 16: Interface classification – Interface type D
TE
TA
TA high-side
TA low-side
GND
Δt
i
Interface type D
fully de-energizing electrical/electronic assemblies and devices of their operating voltage. The
difference from the pure, pulse-switching output of interface type C is primarily the circuitry and the
testing of the return circuit.
Possible return circuit errors such as short circuits can be detected against 0 V. This connection type
prevents voltage carryover through a shared floating 0 V connection point.
There is also the option of a two-channel switch-off over two lines. An individual short circuit on one of
the conductors consequently does not lead to improper switching of the actuator. For this, the source
transmits test pulses to the sink, which are in turn evaluated by the source. The test pulses are
neither distorted nor delayed by the sink.
The sink, e.g. PMC SR6 safety module, can contain inductive, capacitive and ohmic portions. The
source is typically a safety controller or a safety relay with a bipolar output.
6
See ZVEI, p. 17ff.
Manual PMC SR6 safety module
1005344-en-US-01
Intern
+
Source
TE
TE
GND
Test Pulse Generation
Test Pulse Assessment
Test pulse evaluation high-side switch
Test pulse evaluation low-side switch
Reference potential
Timespan
6
is intended either for safely switching actuators (contactors, motors, valves) or for
Sink
Dt = 0
+
GND
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