7. POSITIONING CONTROL
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[Caution]
(1) The number of controllable axis cannot be changed while control is in progress.
(2) Positioning control to the pass points can use a combination of the absolute
data method (ABS!) and the incremental method (INC!).
(3) A pass point can be designated as an address which results in a change in
travel direction.
However, a servo error or some other error may occur if acceleration
processing occurs at a pass point for 1-axis constant-speed control but no
acceleration or deceleration processing occurs at the pass point for 2 to 4-axes
constant-speed control.
(4) Speed change is possible after start
Note the following points when changing the speed.
(a) If constant-speed control includes circular interpolation using center point
designation
Error compensation (see Section 4.4.3) may not function normally if the
speed is changed when a discrepancy (within the allowable error range for
circular interpolation) exists between the designated end-point address and
the arc path calculated from the start address and center-point address.
Therefore, if the circular interpolation using center point designation
positioning method is used under constant-speed control, ensure that the
set start address, center-point address, and end address lie correctly on the
arc.
(b) If both a servo program and the CHGV instructions are used for the speed
change in the same program
The lower of the speed changed by the CHGV instructions and the speed
set by the servo program is selected.
The CHGV instructions are executed if the changed speed is lower than the
speed set in the servo program; otherwise the CHGV instructions are not
executed.
1) If CHGV changed speed > servo program set speed
The speed set in the servo program is selected.
V
t
Speed in servo program
CHGV instructions changed speed
Speed change to servo program commanded speed
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