Siemens SINUMERIK 840D Description Of Functions page 138

3 Safety-Related Functions
3.10 Safe programable logic (SPL) (840D SW 4.4.18)
It is, therefore, possible to handle general machine functions in the SPL
(hydraulics, EMERGENCY STOP) before the axis is commissioned.
This is only possible in the commissioning state of the SPL
($MN_PREVENT_SYNACT_LOCK[0,1]==0 and DB18.DBX36.0==0.
The state is displayed when the SPL starts using Alarm 27095 "%1 SPL
protection not activated".
If an attempt is made to start the SPL in the protective state (after
commissioning has been completed) without the axial safety function having
been activated, then Alarm 27096 is output. The SPL is started if the SPL
crosswise data comparison is not activated.
Data is cyclically exchanged between the PLC and NCK to check the operation
Crosswise data
comparison of the two SPLs (PLC and NCK). Just the same as the comparison between the
NCK and the drive, it cross-checks the signals that arrive at the SPL, the
safety-relevant signals generated by the SPL as well as internal markers.
The monitoring clock cycle for the crosswise data comparison of SPL variables
is permanently set to 1 s (or 10 s $A_CMDSI).
The following signals are included in the crosswise data comparison between
the NCK and the PLC:
$A_INSE[1 ... 64]
$A_OUTSE[1 ... 64]
$A_INSI[1 ... 64]
$A_OUTSI[1 ... 64]
$A_MARKERSI[1 ... 64]
To ensure that this crosswise data comparison functions correctly, the user
must observe the following points:
Limitations Both channels (NCK/PLC) must execute the same logic.
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3-138
SINUMERIK 840D/SIMODRIVE 611 digital SINUMERIK Safety Integrated (FBSI) - Edition 11.03
Cleared SPL-SGAs are the safe state of SPL.
Do not implement any response sequences or sequence controllers that
are controlled externally using short input pulses. This is because short
pulses of this type may only be acquired and processed in one channel
because of sampling effects.
Unused inputs/outputs/markers of the SPL must be given the default
value = 0, single-channel use of individual bits for non-safety-relevant
purposes is not permissible.
An exception is the block $A_INSI(P) (only up to SW 4.4.29, 5.3.1). Such
signals are assigned the value "1" by the software in order to make it
easier to combine the signals of several axes. This function must be
emulated by the user on the PLC side (default of the system variables
$A_INSIPD[1,2] in DB 18 during run-up with "FFFFFFFF"(H). For SW 5.3.1
and higher, the system behavior with respect to $A_INSI is exactly the
same as for other system variables (can be set using MD 10095:
$MN_SAFE_MODE_MASK).
External STOPs must be enabled (are also used internally) and can be
extracted from the SPL if required. The "external STOP A" must be
parameterized at the SPL interface for all safety axes via
MD $MA_SAFE_EXT_STOP_INPUT[0]. If this condition is not fulfilled,
then Alarm 27033 is output.
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11.03