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

05.08
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 mod-
ule 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–related 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
outputs (for the forced checking procedure) are required for the fail–safe connec-
tion 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 termi-
nals, 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 2008 All Rights Reserved
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 05.2008 Edition
7.1 Safety–related input/output signals
F–DI
VS
e.g.
Emergency
To activate and
Stop or user
de–activate
agreement
Connecting Sensors/Actuators
ET 200S PROFIsafe
Test output
Please 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
7-193