
B–62073E–1/042. INTERFACE BETWEEN CNC AND PMC–NA OR NB
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2.3.35 Spindle synchronization signals for the serial interface spindle
In a machine having two spindles such as a lathe, the two spindles must rotate at an identical spindle speed
on the following occasions: When a workpiece held by the first spindle is passed to the second spindle while
the spindles are rotating, and when the first and second spindles are holding an identical workpiece and they
are accelerated or decelerated.
When a workpiece with an irregular shape is passed from one spindle to the other, the spindles must also be
in the same phase of rotation (angular displacement).
Spindle synchronization signals are used to synchronize the two spindles as described above.
(1) Method of spindle synchronization
(a) When the spindle synchronization command is specified while the two spindles are rotating at different
speeds (either of them may stop), the spindles are immediately accelerated or decelerated and syn-
chronized at the specified spindle speed.
(b) If the spindle speed to be detected in synchronization is changed after the two spindles are synchro-
nized, the two spindles are synchronously accelerated or decelerated with the time constant specified
in the parameter and achieve the new spindle speed.
When the spindle speed to be detected in synchronization is set to 0 rpm, the two spindles synchro-
nously stop.
(c) When the spindle synchronization command is specified with the spindle speed to be detected in syn-
chronization set to 0 rpm, the two spindles are immediately stopped and synchronized (stop state).
If the spindle speed to be detected in synchronization is changed after that, the two spindles are accel-
erated while they synchronously rotate with the time constant specified in the parameter and achieve
the new spindle speed.
(d) If a workpiece with an irregular shape is passed from one spindle to the other, the spindles must also
be in the same phase of rotation (angular displacement).
If the spindle phase synchronization command is entered while the spindles are synchronously rotat-
ing, the spindles are rotated to be in the same spindle phase as specified in the parameter (the speed
changes momentarily). Then the two spindles are synchronized again.
If a parameter is specified so that the reference positions of the two spindles agree with each other,
the spindles can be in the same phase of rotation.
(e) If the spindle phase synchronization command is entered after the spindles are synchronized at a
spindle speed of 0 rpm, the spindles stop after rotating to be in the same phase as specified in the
parameter.
It looks as if the spindles are positioned (spindle orientation) while they are stopped.
As a result of the synchronization, the reference positions of the spindles agree with each other.
(Phase synchronization)
If the spindle speed to be detected in synchronization is changed after the two spindles hold an identi-
cal workpiece with an irregular shape, the spindles are accelerated while they synchronously rotate
with the time constant specified in the parameter and achieve the new spindle speed.
(f) Even when the two spindles synchronously hold an identical workpiece, constant surface speed con-
trol can be executed.
The spindle speed is changed by the time constant within the range specified in the parameter even
if a change in speed exceeding the range is specified.
(2) Operation overview
This function can be executed only when the BMI interface is used. (It cannot be executed with the FS3/6
interface.)
When the spindle synchronization signal is entered from the PMC, the system enters the spindle synchro-
nization mode.
The spindle speed synchronization completion signal, MSPSYC, indicates that the spindles are synchro-
nized. While the signal is on, the spindles are synchronized. The spindle speed command specified during
this period is handled as the command specifying the spindle speed to be detected in synchronization.
The identical spindle speed is specified for both spindles. When the spindle speed is changed during this
period, the spindles are synchronously accelerated or decelerated.