Siemens SINUMERIK 840D sl Function Manual page 210

Connecting Sensors/Actuators
7.3 Safe programmable logic (SPL)
Three shutdown inputs E1 to E3
Two acknowledge inputs Q1 and
Q2
Three timer initialization values
TI1 to TI3
One timer limit value TM1
Four output values A1 to A3
Initialization in the part program
The connections for the function block are defined when initialized. The input and
output quantities of the function block are assigned to the required system vari-
ables ($A_MARKERSI, $A_INSE, $A_OUTSE,...). The following functions must be
called:
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SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 03.2006 Edition
If one of these inputs is set to 0, direct output A0 is set
to 0. Outputs A1 toA3 switch with the delay of timer
1–3. If one of these inputs is not used, then it is
internally set to "1" as static signal.
One of these inputs must also be used to initiate test
operation of the safety relay (forced checking
procedure).
Q1 must be supplied with the signal from the real
acknowledge button.
Q2 is only used to automatically acknowledge the
safety software relay as part of the forced checking
procedure. The software relay itself does not have to
be subject to a forced checking procedure. However, if
the Emergency Stop function is executed and if
external actuators have be subject to a forced
checking procedure, if the relay drops-out during the
Emergency Stop test, then it can be acknowledged
using Q2 (in a defined time window, refer to TM1). This
input must also be connected with a safety system
variable (even if the signal is not used) - preferably with
a $A_MARKERSI - in order to detect that this
acknowledge signal is available as steady-state signal
in the crosswise data comparison with the PLC. The
associated comparison data in the PLC must have a
steady-state 0 signal level (error detection using
different states of the particular SPL marker for the
PLC and NCK).
The times after which outputs A1 to A3 are switched to
0 at a negative edge in output signal A0 are defined
here.
This limit value is used to define the maximum time
that the shutdown inputs E1 to E3 (and their AND logic
operation) may have been at a 0 signal level so that
they can still be acknowledged using Q2. This
therefore guarantees that Q2 can only be effective as
automatic acknowledgment for the forced checking
procedure within a defined time window after the relay
has dropped-out (after it has been de-energized). It is
not permissible that Q2 is used to acknowledge a "real"
shutdown.
A0 supplies the result of ANDing E1 to E3 without any
delay. Outputs A1 to A3 supply the same result for
positive edges of A0; for negative edges, the results
are delayed by the timer initialization TI1 to TI3.
A0 to A3 do not produce a result after booting until an
acknowledgment has been received via Q1.
© Siemens AG, 2006. All rights reserved
03.06