8. COORDINATE SYSTEM
The point that is specific to a machine and serves as the reference of the
machine is referred to as the machine zero point. A machine tool builder
sets a machine zero point for each machine.
A coordinate system with a machine zero point set as its origin is referred
to as a machine coordinate system.
A machine coordinate system is set by performing manual reference
position return after power–on (see III–3.1). A machine coordinate
system, once set, remains unchanged until the power is turned off.
(G90)G53 IP _ ;
IP _; Absolute dimension word
When a command is specified the position on a machine coordinate
system, the tool moves to the position by rapid traverse. G53, which is
used to select a machine coordinate system, is a one–shot G code; that is,
it is valid only in the block in which it is specified on a machine coordinate
system. Specify an absolute command (G90) for G53. When an
incremental command (G91) is specified, the G53 command is ignored.
When the tool is to be moved to a machine–specific position such as a tool
change position, program the movement in a machine coordinate system
based on G53.
When the G53 command is specified, cancel the cutter compensation, tool
length offset, and tool offset.
Since the machine coordinate system must be set before the G53
command is specified, at least one manual reference position return or
automatic reference position return by the G28 command must be
performed after the power is turned on. This is not necessary when an
absolute–position detector is attached.
When manual reference position return is performed after power–on, a
machine coordinate system is set so that the reference position is at the
coordinate values of (
α, β) set using parameter No.1240.
Machine coordinate system
D Selecting a machine
coordinate system (G53)
D Cancel of the
D G53 specification