Siemens Sinumerik 840D sl Function Manual page 294

Connecting Sensors/Actuators
7.5 Safe programmable logic (SPL)
S When changing the machine data $MN_PREVENT_SYNACT_LOCK[0,1] from
zero to values not equal to zero, an option set for the SPL inputs and outputs
and an SPL file under /_N_CST_DIR/_N_SAFE_SPF, then Alarm 27098 "SPL
commissioning phase complete" is initiated. This can only be acknowledged
with a power on and should be used as information for the user, that
a) the SPL protective mechanisms (see Table 7-6) are activated
b) a restart is necessary in order to activate these protective mechanisms.
S System variables $A_OUTSI, $A_OUTSID, $A_OUTSE, $A_OUTSED,
$A_MARKERSI, $A_TIMERSI, $A_CMDSI, $A_FSDP_ERR_REAC,
$A_FRDP_ERR_REAC and $A_FRDP_SUBS are protected from being written
to by programs other than the NCK--SPL (/_N_CST_DIR/_N_SAFE_SPF). If an
error occurs, Alarm 17070 "Channel %1 block %2 data item write--protected" is
output.
S A reference checksum is calculated when booting and for changes/saving the
file by the NCK--SPL (/_N_CST_DIR/_N_SAFE_SPF) -- it is entered into the
program as a comment:
Example:
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.
S The system variables $A_INSIP(D), $A_OUTSIP(D), $A_INSEP(D), $A_OUT-
SEP(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.
Table 7-6 Response to SPL errors
Event
Crosswise data comparison
NCK- -PLC identifies an error
SPL program file is to be changed
(written, deleted, re- -named, edited)
7-294
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
; SAFE_CHECKSUM = 000476bbH
MD11500 $MN_PREVENT_
SYNACT_LOCK[m,n] equal to 0
Alarm 27090 is triggered
No response
MD11500 $MN_PREVENT_
SYNACT_LOCK[m,n] not equal to 0
Alarm 27090 is triggered and in
addition, STOP D/E is triggered
Alarm 27093 is initiated
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