Sensor Connection Using The 4-Terminal Concept - Siemens SINUMERIK 840D sl Function Manual

03.06
IM 151–1
High Feature
PROFIBUS
with
PROFIsafe
Fig. 7-6 Sensor connection using fail-safe inputs according to the 3-terminal concept
7.1.4

Sensor connection using the 4-terminal concept

For the 4-terminal concept, four terminals are required at the fail-safe input module
to connect a sensor that utilizes a contact (e.g. Emergency Stop pushbutton).
Faults/errors in the sensors and actuators can be detected in conjunction with the
SPL-crosswise data comparison and forced checking procedure or the forced
checking as a result of the process itself. The connecting cables are generally
monitored autonomously by the fail-safe input module.
The following applies to the safety-relevant sensor connection:
2 safety inputs + 2 standard test outputs
Example
2 inputs (to read-in the 2-channel sensor signals via SGE) and 2 standard test out-
puts (for the forced checking procedure) are required for the fail-safe connection of
a sensor. The test outputs are supplied from the two power supply voltages (VS1,
VS2) of the safety input module. For the connection concept with 4 terminals, both
equivalence (NC contact/NC contact, NO contact/NO contact) as well as non-
equivalence (NC contact/NO contact) contact versions are possible.
© Siemens AG, 2006. All rights reserved
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 03.2006 Edition
7.1 Safety-relevant input/output signals
F-DI
VS
e.g.
Emergency
To activate and
de-activate Stop or user
agreement
Connecting Sensors/Actuators
ET 200S PROFIsafe
Test output
Note: In this case, it is not possible to
connect the buttons in series!
Non-equivalence
contacts (NC
contact/
NO contact)
with the
3-terminal
concept
7-173