Siemens SINUMERIK 840D sl Function Manual page 857

System variables
The braking position can be scanned via system variable $AA_OSCILL_BREAK_POS1,
when approach to reversal position 1 is aborted or via
$AA_OSCILL_BREAK_POS2 when approach to reversal position 2 is aborted.
If the relevant reversal point is approached again, the position of the reversal point can be
scanned in $AA_OSCILL_BREAK_POS1 or $AA_OSCILL_BREAK_POS2.
In other words, only after an
between the values in $AA_OSCILL_BREAK_POS1 and $AA_OSCILL_REVERSE_POS1 or
the values in $AA_OSCILL_BREAK_POS2 and $AA_OSCILL_REVERSE_POS2.
External oscillation reversal
examples.
Special cases
If the PLC input signal "oscillation reversal" is activated as the axis is approaching the start
position, the approach movement is aborted and the axis continues by approach interruption
position 1.
If the PLC input signal "oscillation reversal" is set during a stop period, the stop timer is
deactivated; if exact stop fine has not yet been reached, the axis waits for the exact stop fine
reached signal before continuing its motion.
If the PLC input signal "oscillation reversal" is activated as the axis is approaching the end
position, the approach movement is aborted and oscillation is terminated.
An example of oscillation reversal can be found in the chapter "Changing Reversal Position
with 'External Oscillation Reversal' via Synchronous Actions".
12.4 Marginal conditions
Availability of the "Oscillation" function
Oscillation is an option, available under order number 6FC5 251-0AB04-0AA0.
Asynchronous oscillation and oscillation across blocks is available for NCU570, 571,
572, 573.
Oscillation with motion-synchronous actions is available for NCU 572, 573.
Extended Functions
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
External oscillation reversal
can therefore be detected by a synchronized action, see
Oscillation (P5)
Marginal conditions
command is there a difference
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