2.8.8 INCHIMETRIC DESIGNATION BY G CODE
(G 20, G 21)+
Unit of measurement (metric or inch) of input
data is selectively specified by the following G
codes.
These G codes are programmed at the leading
end of a block of its own.
If these G codes
are commanded, the units of all the following
motions are than ged.
a.
Subsequent part programs
b.
Tool offset values
c.
part of settings and parameters
d.
Part of manual movements
e.
Displays
Notes :
1. When G20 or G 21 is commanded, the setting
of inch/metric selection is changed.
There-
fore, the state of G20/G21 at the time of
power application depends on the setting
by parameter #6001D0.
EXAMPLE
1
ER
CR
01234 ;
G20 ;
T
Inch input designation
2.
a.
b.
When G 20 /G 21 selection is commanded in the
program, take the following procedure be-
forehand.
Cancel work coordinate system ( G50T ) , if
used.
Cancel tool position offset, and tool radius
b.
In principle,
make the display reset opera–
tion when current position display (exter-
nal) is useci.
4.
The tool offset values are processed differ-
ently in the G20 mode and the G21 mode.
G 20/G21 must be commanded after modifying
the tool offset values.
4
Stored Offset
Processing in G 20 I Processing in G 21
Values (Inch)
(Metric)
15000
I
1,5000 in.
15.000 mm
2,8.9 RADIUS PROGRAMMING FOR CIRCULAR iNTER-
POLATION (G 22, G 23)+
In programming, circular interpolation (G02, G03) ,
the control requires the data of the arc-center
coordinates.
Normally, they are given by using
the addresses I and K.
(1) In programming of G2.2 or G23, the control
automatically calculates the arc center coor–
dinates (1 , K) from the radius value desig-
nated by the address R and performs circular
interpolation.
G22
1
X( IJ) . . . Z(W) . . . R.. . F(E) . . . ;
( G23)
A tool moves along the circular arc whose
center is radius R away from the present
position. The end point of arc is at coor–
dinates (x,
Z) set by G50 or is away from
the present position by (U, W) . Tool moves
along the circular arc at feedrate designated
by F code.
(2) The meanings of G22, G23 and each address
are shown below.
(3) Designaticm of radius value R
Radius value R is commanded by incremental
value with a sign of radius programming.
In this case,
When radius value R > 0, an arc, describing
less than 180°, and when R < 0, an arc
describin~; more than 180° are specified.
compensation (G41 – G44) .
3.
Take the following procedure after the com-
mand of G20/G21 selection.
a. Program absolute zero point for all axes
before move command (G50) .
33
To Next Page
Loading...
