Description Of The System Variables - Siemens SINUMERIK 840D sl Function Manual

05.08
Table 8-10 Overview of system variables
$AC_SAFE_SYNA_ Free safety synchronized action
MEM elements
Note:
r –> read, w –> write
An implicit preliminary stop is generated
Only permitted in the commissioning phase
1)
The number of these system variables depends on the option SI Basic or SI Comfort. For SI Basic, the following
applies:
4 INSE[1..4]
4 OUTSE[1..4]
4 INSED[1]
4 OUTSED[1]
8.4.2

Description of the system variables

System variable $VA_IS
The safe actual value, used by SI, can be read and further processed by the NC
part program for every axis/spindle.
Example:
When an NC part program is started, Safety Integrated checks whether axis X
would move into the vicinity of shutdown limits as a result of the zero offsets when
a program is processed. The part program can be programmed as follows, for
example:
IF ($VA_IS[X] < 10000) GOTOF POS_OK
MESG ("Axis has nearly reached limit switch!")
POS_OK:
...
The variable can also be used in synchronous actions in order to reduce the over-
ride when the axis is nearly at the limit switch.
Difference between $VA_IS and $AA_IM
Both variable $VA_IS and variable $AA_IM can be used to read actual values.
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SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 05.2008 Edition
[0,MAX_INT]
; if the actual value is too high,
; then the following message,
; otherwise, continue here
Data Description
8.4 System variables
r w r w
x x
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