Safety Integrated Basic Functions
10.9 Control via TM54F
Drive functions
704 Function Manual, 11/2017, 6SL3097-4AB00-0BP5
● Fail-safe configuration with 2 digital inputs per F-DI
● Input filter to block test signals with an adjustable suppression time (p10017)
● Configurable connection of NC/NC or NC/NO contacts using p10040
● Status parameter r10051
● Adjustable time window for monitoring discrepancy at both digital inputs by means of
parameter p10002 for all F-DIs
Note
Discrepancy time
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.
Incorrect switching states in the switched-off state as a result of quiescent currents
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 – and as a consequence, to death or severe injury –
if digital inputs are not connected correctly.
• You must observe the conditions for digital inputs/outputs specified in the relevant
manufacturers documentation.
• Only use outputs that have a maximum quiescent current of 0.5 mA when in the "OFF"
state (according to IEC 61131 Part 2, Chapter 5.2 (2008))
You can find additional information on this topic in the Internet at: Parameterizing and
configuring safety hardware (http://support.automation.siemens.com/WW/view/de/39700013)
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