Siemens Sinamics S110 Function Manual page 334

Safety Integrated Functions
8.6 Controlling the safety functions
Description
Failsafe digital inputs (F-DI) consist of two digital inputs. The cathode of the optocoupler is
routed to the second digital input in order to allow the connection of an M-switching F-DO
output (the anode must be wired to 24 V DC).
Parameter p10140 is used to determine whether an F-DI is operated as NC/NC or NC/NO
contact. The status of each DI can be read at parameter r0722. The same bits of both drive
objects are logically linked by AND operation and return the status of the relevant F-DI.
Explanation of terms:
NC contact / NC contact: To select the safety function, a "zero level" must be present on
both inputs.
NC contact / NO contact: To select the safety function, a "zero level" at input 1 and a "1
level" at input 2 must be present.
The signal states at the two associated digital inputs (F-DI) must assume the same status
configured in p10140 within the monitoring time set in p10002.
Figure 8-12 Overview of F-DI 0 ... 2
334
Function Manual, 10/2008, 6SL3097-4AB10-0BP0
Drive functions