Section:
Page
PROGRAMMING
24
Chapter: 6
6.7.2 G47, G48 AS OPENING OF THE AXIS LOOP
In particular applications such as presses, metal forming machines, sheetmetal forming
machines, etc., the part undergoes a movement or pull while it is machined.
By means of functions G47, G48 the CNC allows the loop of the axis undergoing the pull
to be opened or closed.
When the position loop is closed, in normal operating mode, the CNC controls the axis
feedrate at all times.
When the position loop is opened the axis operates in DRO mode, that is, the CNC does
not control the feedrate of the axes but does take into account their movements.
Example of sheetmetal forming machines:
Normal operation is with the position loop closed.
When the tube forming is to be done the following steps must be taken:
- Open the position loop of the axis undergoing the pull and the axis starts to operate
in DRO mode.
- Form the tube. The CNC displays at all times the position coordinate of both axes,
that is, it accurately reflects the tugs undergone by the tube.
After forming the tube close the axis position loop again.
In order to be able to use functions G47, G48 as opening for the axis loop machine parameter
"P101(3)=1" has to be set.
The programming formats of this function are:
G47 X
Opens the position loop of axis X.
G47 Y
Opens the position loop of axis Y.
G47
Opens the position loop of both axes
G48 X
Closes the position loop of axis X.
G48 Y
Closes the position loop of axis Y.
G48
Closes the position loop of both axes.
Attention:
Functions G47 and G48 are modal.
The block containing function G47 or G48 cannot contain other functions
(X, Y, F, S, T, etc.)
If a movement block of an axis operating in open position loop is executed,
the CNC will display the corresponding error code.
On power-up, after executing an M30 or after an Emergency or Reset, the
CNC assumes function G48.
SPECIAL FUNCTIONS
