Siemens SINUMERIK 840D sl Function Manual page 517

This means that signal differences between the NCK and PLC system variables can be
tolerated for up to 10 seconds without Alarm 27090 being output.
This system variable can be read and written into by the user program.
System variable $A_LEVELSID
This system variable is used to display the stack level of the signal change monitoring in the
crosswise data comparison between NCK and PLC. This variable indicates the current number
of signals to be checked by the crosswise data comparison function.
System variables $A_xxxP(D)
Images (mapping) of the PLC-SPL interface and markers are provided to make it easier to
commission the SPL. The system variables are updated in the same clock cycle as the
crosswise data comparison between the NCK and the PLC.
These system variables can only be accessed reading.
These system variables may only be used in the commissioning phase.
As soon as commissioning has been signaled as completed, access to these system variables
is blocked. If these program commands are processed, Alarm 17210 is output to indicate an
error condition.
System variables $A_INSIP[1...192]
Images of the PLC-side internal SPL input signals (status signals from the drive monitoring
channel) can be read using these system variables.
Associated DB18 values: DB18.DBX54.0 ... DBX61.7 ([1...64])
DB18.DBX304.0 ... DB18.DBX319.7 ([65...192])
System variables $A_INSIPD[1...6]
Images of the PLC-side internal SPL input signals (status signals from the drive monitoring
channel) can be read in a double-word-serial fashion (32 bit) using these system variables.
Associated DB18 values: DB18.DBD54, DBD58
System variables $A_OUTSIP[1...192]
Images of the PLC-side internal SPL output signals (control signals to the drive monitoring
channel) can be read using these system variables.
Associated DB18 values: DB18.DBX62.0 ... DBX69.7 ([1...64])
DB18.DBX320 ... DBX335.7 ([65...192])
System variables $A_OUTSIPD[1...6]
Images of the PLC-side internal SPL output signals (control signals to the drive monitoring
channel) can be read in a double-word-serial fashion (32 bit) using these system variables.
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
Data descriptions
9.7 System variable
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