
B-63783EN-1/01 13.MEASUREMENT
- 1395 -
13.5 SKIP FUNCTION
13.5.1 Skip Function
General
Linear interpolation can be commanded by specifying axial move
following the G31 command, like G01. If an external skip signal is
input during the execution of this command, execution of the command
is interrupted and the next block is executed.
The skip function is used when the end of machining is not
programmed but specified with a signal from the machine, for example,
in grinding. It is used also for measuring the dimensions of a
workpiece.
The coordinate values when the skip signal is turned on can be used in
a custom macro because they are stored in the custom macro system
variable #5061 to #5068, as follows:
#5061 First axis coordinate value
#5062 Second axis coordinate value
#5063 3rd axis coordinate value
:
:
#5080 20th axis coordinate value
- Feedrate
Two types of feedrate can be selected for the G31 block, using
parameter SFP (bit 3 of No. 1400).
(1) Feedrate specified with address F (may be specified before or in
the G31 block)
(2) Feedrate set for parameter No. 1428
If the feedrate with the G31 command is to conform to the feedrate set
for the parameter to improve the tool position precision when the skip
signal is input, automatic acceleration/deceleration is not performed.
- Compensation for the servo delay
With the input of the skip signal, the current position is stored within
the CNC. The current position within the CNC, however, contains the
delay in the servo system and, therefore, differs from the machine
position by the delay in the servo system. This difference can be
determined from the position deviation of the servo and the remaining
amount due to feedrate acceleration/deceleration performed within the
CNC. If this difference is taken into consideration, the delay in the
servo system need not be included in the measurement error.