Delta RMC151 - Manual (Page 727)

8 Command Reference
To start a synchronized move, issue the Sync Move Absolute (13) or Sync Move Relative
(14) commands simultaneously to each axis that you wish to include in the synchronized
move. Refer to the Issuing Sync Move Commands Simultaneously section below. The
Sync Group command parameter must be set to the same value for each axis to be
synchronized together.
The Position, Speed, Velocity, Acceleration, and Deceleration command parameters for all
synchronized axes in the same group need not be the same. When the commands are
issued, all the command parameters are evaluated and the RMC selects the maximum
speeds and velocities for each axis such that (1) all axis positions are ratioed evenly
throughout the move such that the axes arrive at the same time, (2) no individual axis
exceeds its speed, acceleration, or deceleration parameters. Therefore, when issuing the
Sync move, just set the velocities and accelerations to the maximum value you want on
each axis, then the RMC will automatically ratio them so the axes remain in sync and
arrive simultaneously.
For best results, all axes to be synchronized should be stopped when the Sync Move
command is issued, although they are not required to be (this is required in firmware
prior to 3.31.0). In closed loop control, "stopped" means the Target Velocity is zero; in
open loop control, "stopped" means the Stopped Status Bit is be set. If the axes are
moving (and not already synchronized) when a Sync Move is issued, this may cause
discontinuities in the velocity and may jerk the axis. Changing directions while a sync
move is in progress is not recommended.
Sync Group Details
The Sync Group command parameter is used to define which axes should be
synchronized together. Valid group numbers are zero (0) to ten (10). It is possible to
have multiple sync groups in progress at the same time. The sync group will be valid for
the duration of the synchronized move. Once the Target Positions reach the Command
Positions, the sync move will be complete, the axes no longer belong to that sync group,
and the sync group number will be available for another synchronized move.
Changing a Sync Move In Progress
It is possible to speed up or slow down a sync move that is in progress while still
maintaining the same synchronization ratio. To do so, issue sync move commands to all
the synchronized axes such that the final position for each axis are the same as for the
initial sync move command. It is not recommended that you change the final commanded
positions of a sync move in progress. Doing so will likely cause a step jump in target
speed on one or more axes, and is not allowed prior to 3.31.0 firmware.
Exiting a Sync Move In Progress
To remove an axis from a sync move in progress, issue any non-sync motion command to
the axis. The motion of the remaining axes in the group will be re-evaluated based on
their requested speeds and accelerations. This can cause the profile to speed up or use a
different acceleration/deceleration value.
Synchronized Stop
If you need to stop a sync move in progress, use the Sync Stop (17) command to stop
the axes while maintaining the synchronization.
Halting
If any axis in a sync group receives a Closed Loop Halt, then all axes in that sync group
will halt while maintaining their sync ratios. When the halt is complete, the axes will no
longer belong to the sync group. An Open Loop Halt or Direct Output Halt will
immediately remove the axis from the sync group, and halt all the axis in that sync group
with the same halt.
Notice that an axis can also be a member of a Halt Group as defined by the Halt Group
Number axis parameter. Halts in any group will propagate recursively to other groups. If
an axis halts, all axes in that group will halt, and so will the axes in any other sync groups
or halt groups that the other axes in the group are part of.
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