3 Safety-Related Functions
11.03
3.10 Safe programable logic (SPL) (840D SW 4.4.18)
© Siemens AG 2003 All Rights Reserved
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SINUMERIK 840D/SIMODRIVE 611 digital SINUMERIK Safety Integrated (FBSI) - Edition 11.03
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In order to check the program the status of the active synchronous
actions (operating area "Machine", soft key "Synchronous actions") can
be displayed.
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The program can be modified during commissioning. It must then be re-
started.
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The NCK-SPL program is stored in the NCK path _N_CST_DIR as
subroutine "_N_SAFE_SPF" (MMC view: standard cycles/SAFE.SPF).
Other sub-routine names are not permitted.
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The NCK-SPL program must be started after commissioning.
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The images of the PLC safety variables ($A_INSIP(D), $A_OUTSIP(D),
$A_INSEP(D), $A_OUTSEP(D), $A_MARKERSIP(D) ) are required for
the simulation (NC side) of an SPL. These can be used to develop the
SPL step-by-step. They can only be read by the NCK.
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The synchronous action IDs used for the NCK-SPL are protected from
being influenced by the PLC or other programs using
MD $MN_PREVENT_SYNACT_LOCK. It is then no longer possible to
change these synchronous actions (CANCEL, LOCK have no effect) once
_N_SAFE_SPF has been started.
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The system variables $A_OUTSI, $A_OUTSID, $A_OUTSE, $A_OUTSED,
$A_MARKERSI, $A_TIMERSI and $A_CMDSI are protected from being
written to by programs other than the (/_N_CST_DIR/_N_SAFE_SPF). If
an error occurs Alarm 17070 "Channel %1 block %2 data item write-
protected" is output.
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A reference checksum is calculated at run-up by the NCK-SPL
(/_N_CST_DIR/_N_SAFE_SPF) that is entered into the program as a
comment:
Example:
; SAFE_CHECKSUM = 000476bbH
The checksum is then cyclically re-calculated and compared with the
reference checksum. If a deviation is detected, Alarm 27093 "Checksum
error NCK-SPL, %1, %2, %3" is output.
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The system variables $A_INSIP(D), $A_OUTSIP(D), $A_INSEP(D),
$A_OUTSEP(D) and $A_MARKERSIP(D) are only accessible during the
commissioning phase.
If NCK-SPL execution is interrupted for any reason or the SI system variables
are changed by another program, then this is detected by the cyclic crosswise
data comparison with the PLC.
Protective
mechanisms