Siemens SINUMERIK 840D sl Function Manual page 359

Sequence
Normally, a channel moves a tool in the working area. If several channels are each moving a
tool in the same working area, the tool movements must be synchronized. The following
synchronizations are possible:
● Channel synchronization via the program coordination commands WAITM, WAITMC, WAITE,
START.
● Channel synchronization via the PLC user program and NC/PLC interface signals. For
example, via M function output from the channel to the PLC and read-in disable from the
PLC to the channel.
● Axis interchange: The channel waits until the other channel relinquishes the axis.
● Synchronization by means of global variables in the NC program.
● Cross-channel couplings
● Axis container rotation
● Testing the program including the parallel synchronized actions in the main run and
synchronization of the synchronized actions with the channel.
Under these general conditions, it is almost impossible to just start one channel - it would
remain stationary at the first synchronization location.
With the "channel-by-channel running-in" function, all channels of the group can be started,
and only a few channels, generally just one channel, actually moves its axes. The other
channels are then in the "program test" state.
This is the reason why users must define the channels in which they do not want any motion.
This is made from the user interface in the "Program controls" menu. When selected, the
following channel-specific signal is set in the HMI/PLC interface:
DB21, ... DBX25.7 = 1 (program test selected)
The activation is then made using the channel-specific NC/PLC interface signal:
DB21, ... DBX1.7 = 1 (activate program test)
The feedback signal is sent via the interface signal:
DB21, ... DBX33.7 == 1 (program test active)
Further, for a successful operation, it may be necessary that several axes/spindles - especially
spindles - are actually physically operated, although their channel is in the "program test" state.
The following axis-specific NC/PLC interface signal is used for this purpose:
DB31, ... DBX14.0 (suppress program test)
Example
A system comprises a main spindle and counterspindle. Two slides can operate on both the
main spindle and counterspindle. Each slide is controlled from a separate channel. The main
spindle is in channel 1, the counterspindle in channel 2. Channel 1 is tested and channel 2 is
disabled using the channel-specific NC/PLC interface signal DB21, ... DBX1.7 (activate
program test). The two workpiece spindles - main spindle and counterspindle - play somewhat
of a "special role". A workpiece can be machined, without having to absolutely traverse the
workpiece spindle in real terms in the channel. This is the reason why it is necessary that both
Extended Functions
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
K5: Channel synchronization, axis interchange
6.1 Channel synchronization
359