Page
Chapter: 6
Section:
PROGRAMMING
23
SPECIAL FUNCTIONS
6.7 SPECIAL FUNCTIONS
6.7.1 FEEDBACK INHIBIT (G47, G48)
In some applications, after positioning the part, sheetmetal, etc. it is necessary to correct
its position.
This correction is made by an external device not controlled by the CNC.
When executing function G47, the CNC ignores the possible movements caused by
that device, thus inhibiting the feedback pulses.
The programming formats for this function are:
G47 X It ignores the X axis feedback pulses.
G47 Y It ignores the Y axis feedback pulses.
G47
It ignores the feedback pulses from both axes.
To cancel this feature and return to normal feedback monitoring, program function
G48.
Attention:
G47 is modal.
When G47 is active, the CNC ignores the feedback pulses once the axis
is in position.
If a movement block is executed afterwards (G00, G01, G02, G03,...) the
CNC switches to control the feedback thus preventing the machine from
moving out of control.
Once the programmed movement has ended (reaching position), the CNC
switches back to ignoring the feedback pulses.
If while G47 is active, one or both axes are moved and, then, G48 is
programmed, the CNC does not recover the lost position.
On power-up, after executing an M30, after an Emergency or a Reset, the
CNC assumes G48.
