Siemens SINUMERIK 840C Installation Instructions Manual page 943

12 Functional Descriptions
12.18.14 Special cases of gearbox interpolation
• The same drive may not be configured as the following drive as a C-axis and a spindle in
two GI groupings at the same time.
• Synchronous operation is not cancelled when the operating mode is changed or after
RESET.
• The system limits the speed of the leading spindle to a maximum value which is
determined by the link factor and the spindle limitations of the following spindle (max.
motor speed, max. spindle speed, max. gear stage speed).
• If an M19 gain switchover is implemented for the drive actuator, the following must be
noted: The position control is active in synchronous mode, i.e. the servo gain factor of the
M19 creep speed is applied as the servo gain factor. However, the actuator is not
switched over to M19 mode in synchronous operation. This M19 servo gain factor is not
however rated for maximum speed. Before you activate the link, therefore, you should
switch over to a gear stage which is identical - with the exception of the servo gain factor
(matched to maximum link speed) - to the gear stage of the actuator, which has not been
switched over.
• If the leading and following spindles are friction-locked via a clamped workpiece, the speed
controllers of the spindles may be working in opposition to one another. In such cases, the
I-action component of the speed controller must be reduced; the function can also be
activated via interface signals "Cancel synchronism deviation".
Interface signals
• The spindle override is operative only for the leading spindle in synchronous operation.
• In synchronous operation, the normal spindle interface signals are relevant for the leading
spindle; only the CONTROLLER ENABLE and the extended signals of the following spindle
are relevant for the following spindle and the synchronous operation status.
• When the SPINDLE DISABLE signal is applied to the leading spindle, then the same signal
is set internally for the following spindle.
• Synchronous operation is not aborted if the signal SPINDLE DISABLE is set at the follo-
wing spindle interface or the CONTROLLER ENABLE signal removed. Since, however, the
following spindle is then stationary, the monitoring circuit for emergency retraction or
synchronism responds as soon as the leading spindle rotates and the monitoring threshold
is exceeded.
• If the signal PLC SPINDLE CONTROL is applied to the following spindle, then the G400,
G402 and G403 commands are also blocked. The last command in each case is executed
after reset of the signal.
• If the CONTROLLER ENABLE signal for the following spindle is removed after spindle stop
without the link being deactivated at the same time, then a synchronism error caused by
external action (e.g. manual rotation, drift, etc.) will not be compensated when the
CONTROLLER ENABLE signal is applied again.
This may cause loss of the defined allocation between leading and following spindle for
some applications (e.g. polygonal turning). This problem can be remedied by starting "On-
the-fly synchronization" with the appropriate synchronous positions from the PLC interface.
Gear stage
• Before synchronous operation is selected, the same mechanical gear stage must always
be engaged for the following spindle so that the same position control parameters are
always applied for the following spindle.
• No request for a gear change may be present when synchronous operation is selected.
12–168
© Siemens AG 1992 All Rights Reserved
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SINUMERIK 840C (IA)