Siemens SINUMERIK 840Di sl Function Manual page 83

Axis coordination
If a positioning command (POS, MOV) is started from synchronized actions for an axis that
is already operating as a path or PLC axis, then processing is aborted with an alarm.
Axis movement by PP and SA alternately
In typical cases, an axis is either moved from the part program (PP) in motion blocks or as a
positioning axis from a synchronized action (SA). However, if the same axis must be
traversed alternately from the part program as a path axis or positioning axis and from
synchronized actions, then a coordinated transfer takes place between both axis motions.
Example
; traverse X axis alternately from part program and from synchronized actions
N10 G01 X100 Y200 F1000
...
N20 ID=1 WHEN $A_IN[1]==1 DO POS[X]=100 FA[X]=200
...
CANCEL(1)
...
N100 G01 X100 Y200 F1000
On-the-fly transitions
Transitions can be made between command axes and spindles.
Starting point
Since several synchronized actions can be active simultaneously, the situation may arise
where an axis motion is started when the axis is already active.
Response
In this case, the most recently activated motion is applicable. POS- and MOV motions can be
activated alternately.
When a reversal in the direction of motion is forced in this manner, the axis is first
decelerated and then positioned in the opposite direction.
Synchronized actions
Function Manual, 11/2006, 6FC5397-5BP10-2BA0
2.4 Actions in synchronized actions
; X axis programmed in part program
; Start positioning from synchronized action,
; when digital input is present
; Select synchronized action
; X: Path axis
; Period of delay before motion, when digital
; input was 1 and hence X from
; Synchronized action was positioned
Detailed description
83