Siemens Sinamics S120 Function Manual page 192

Cont rol of the safety functions
5.4 Control via TM54F
F-DI features
● Fail-safe configuration with 2 digital inputs per F-DI
● Input filter to block test signals with an adjustable suppression time (p10017), see
Chapter "Bit pattern test (Page 173)".
● Configurable connection of NC/NC or NC/NO contacts by means of p10040
● Status parameter r10051
● Adjustable time window for monitoring discrepancy at both digital inputs by means of
parameter p10002 for all F-DIs
Not e
Dis crepancy t ime
To avoid incorrect triggering of fault messages, at these inputs the discrepancy time must
always be set less than the shortest time between 2 switching events (ON/OFF, OFF/ON).
● Second digital input with additional tap of the optocoupler cathode for connecting a
ground-switching output of a fail-safe controller.
● The signal states of the two digital inputs of the F-DIs are frozen at logical 0 (safety
function selected) when different signal states are present within a failsafe F-DI until a
safe acknowledgment has been carried out by means of an F-DI via parameter p10006
(SI acknowledgment internal event input terminal).
● The monitoring time (p10002) for the discrepancy of the two digital inputs of an F-DI may
have to be increased so that switching operations do not trigger an undesired response,
thereby necessitating a safe acknowledgment. Therefore, the signal states at the two
associated digital inputs (F-DI) must have the same state within this monitoring time,
otherwise the following fault will be output F35151 "TM54F: Discrepancy error". This
requires safe acknowledgment.
Danger to life due t o incorrect s witching states c aused by quiescent currents in the
s witched-off state
In contrast to mechanical switching contacts (e.g. Emergency Stop switches), quiescent
currents can still flow through semiconductor switches even when they are switched off.
This can lead to false switching states if digital inputs are not connected correctly.
• Pay attention to the conditions for digital inputs/outputs specified in the relevant
• Use only outputs that have a maximum quiescent current of 0.5 mA when "OFF" (in
More information on this topic is available on the Internet at: Parameterizing and configuring
safety hardware (http://support.automation.siemens.com/WW/view/de/39700013)
192
WA RNING
manufacturer documentation.
accordance with IEC 61131 part 2, Chapter 5.2 (2008)).
Function Manual, (FHS), 07/2016, 6SL3097-4AR00-0BP6
Safety Integrated