
11. PROGRAM COMMAND
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Indexing the table on a machining center is a complished by specifying
a positioning angle.
Before and after indexing, the table is automatically unclamped or
clamped .
The control axis that indexes the table can be named A, B or C. It will
be referred to as “B” in the following discussion.
The positioning angle for the table is commanded by the numbers
following “B” in the part program block. Both absolute and incremental
commands are possible. The value for absolute “B” is based on the
increment system.
(Example) G00G90B100000; Absolute command
(Positioning angle 10 degrees)
G00G91B20.0; Incremental command
(Move distance 20 degrees)
There are two variations of the procedure (type A and type B) to set the
index table position. The difference is in the ON/OFF timing of the
position control servo. The sequence of events timing charts and the
difference between the variations are described below.
(1)Assume Bbbbb is ordered by the command program.
(2)The CNC turns the B axis unclamp signal BUCLP <F061#0> to “1”.
(Type B -- When BUCLP is turned to “ 1 ”, the position control servo
for the B axis is turned ON.)
(3)When the unclamp process is completed, the PMC sets the axis
unclamp signal *BEUCL <G038#6> to “0”.
(4)The CNC then sets the B axis unclamp signal BUCLP to “0” indicating
it received the *BEUCL signal.
(5)When the PMC is notified that BUCLP has been set to “0”, the PMC
should set *BEUCL to “1”.
In type B, B–axis unclamp signal BUCLP is set to “0”, B–axis position
control is made with servos active, B–axis is rotated, and the B axis
is stopped at the specified position. B axis always moves at rapid
traverse.
(6)When the B axis stops at the specified position, the CNC sets the
B–axis clamp signal BCLP<F061#1>to 1. In type A, signal BCLP is
set to “1” and B–axis position control is made with servo off.
(7)When BCLP is set to “1” on the PMC side, the B axis is clamped
mechanically (with a clutch or shot pin, for example). When the clamp
is completed, the B axis clamp completion signal *BECLP <G038#7>
is set to “0”.
(8)When *BECLP is turned to “0”, the CNC then sets BCLP to “0”. (Type
B -- When BCLP turns to “0”, the B axis position control servo is
turned off.)
11.9
INDEX TABLE
INDEXING FUNCTION
(M SERIES)
General
Basic Procedure