System Variables - Siemens SINUMERIK 840D Function Manual

3.2.7

System variables

Reference/actual state
The reference and actual state of the "travel to fixed stop" function can be read using the
following system variables:
● $AA_FXS = <value> (status, "Travel to fixed stop" reference state)
● $VA_FXS = <value> (status, "Travel to fixed stop" actual state)
<val‐
ue>
0
1
2
3
4
5
Additional information
If errors occurred when traversing to the fixed stop ($VA_FXS == 2), then additional information
is displayed in the following system variables:
● $VA_FXS_INFO = <value> (additional information when "traveling to fixed stop")
<val‐
ue>
0
1
2
3
4
5
6
Application example for $AA_FXS
In order that a block change is executed, no alarm should be triggered when a fault occurs. The
cause is then determined using the system variable $VA_FXS_INFO and a specific response
initiated.
Requirement: MD37050 $MA_FIXED_STOP_ALARM_MASK = 0 (when traveling to fixed stop,
no alarm initiated)
Program code
X300 Y500 F200 FXS[X1]=1 FXST[X1]=25 FXSW[X1]=5
IF $AA_FXS[X1] == 2 GOTOF FXS_ERROR
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
Description
Axis is not at fixed stop
Fixed stop was successfully approached
Approach to fixed stop failed
Selection "Travel to fixed stop" is active.
Fixed stop was detected.
Travel to fixed stop deselection active
Description
No additional information available
No approach motion programmed
Programmed end position reached, motion stopped
Cancellation using a reset, DB21, ... DBX7.7 == 1
Monitoring window was exited
Torque reduction rejected by drive
PLC has withdrawn the enable, DB31, ... DBX3.1 == 0 (travel to fixed stop enabled)
F1: Travel to fixed stop
3.2 Detailed description
Comment
; Travel to fixed stop
; IF fixed stop == reached
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