Siemens SINUMERIK 840D sl Function Manual page 172

Connecting Sensors/Actuators
7.1 Safety-relevant input/output signals
IM 151–1
High Feature
PROFIBUS
with
PROFIsafe
Fig. 7-5 Actuator connection via fail-safe outputs, e.g. 400 V load circuit – P/M–switching
Example of connecting a sensor
2 safety-relevant inputs (to read-in through 2 channels via SGE) and 1 standard
test output (for the forced checking procedure) are required to connect a sensor in
a fail-safe fashion. The test output is fed from the power supply voltage of the
safety input module. For sensors with a self-test routine, the test output on the in-
put module is not required. For the 3-terminal connection concept we recommend
that sensors with non-equivalence contacts are used (NC contact/NO contact). If a
P or M short-circuit or broken cable at both signal cables, then a signal state is ob-
tained that is not logically permissible. This means, that a cross-circuit fault can be
detected by the non-equivalence concept without having to carry-out any test.
Note
It is not necessary to provide cross-circuit fault detection in the input module.
7-172
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 03.2006 Edition
F–DO
DI
Feedback
signal
ET 200S PROFIsafe
Electronics output – M
24 V load
circuit,
indirect
400 V
Electronics output – P
© Siemens AG, 2006. All rights reserved
03.06
Indirectly position
monitoring of the
load using
positively-driven
contacts