Rockwell Automation Publication 2080-UM002N-EN-E - November 2022
167
Chapter 9 Motion Control
Simultaneous Execution of Two Movement Function Blocks (Busy Output = True)
The general rule is that when a movement function block is busy, then a function block
with
the same instance (
for example, MC_MoveRelative2) cannot be executed again until the
function block status is not busy.
When a movement function block is busy, a function block
with a different instance
(for
example, MC_MoveRelative1 and MC_MoveAbsolute1 on the same axis) can abort the currently
executing function block. This is mostly useful for on-the-fly adjustments to position, velocity,
or to halt after a specific distance.
Example: Move to Position Ignored Due to Busy
MC_MoveRelative, MC_MoveAbsolute will be busy until final position is
reached. MC_MoveVelocity, MC_Halt, and MC_Stop will be busy until final
velocity is reached.
Velocit
y
Time
Execute1
Busy1
Velocit
y
Time
Execute1
Busy1
This command is ignored
Simple move position using one instance
of MC_MoveRelative, MC_MoveAbsolute
For simple moves, the movement
function block finishes. Busy output
indicates that the function block is
executing and must be allowed to
finish before Execute input is toggled
again.
If Execute is toggled again before
Busy is false, the new command is
ignored. No error is generated.