82 Rockwell Automation Publication 2080-UM002L-EN-E - November 2021
Chapter 7 Motion Control
Motion Control Function
Blocks
Motion control function blocks instruct an axis to a specified position,
distance, velocity, and state.
Function Blocks are categorized as Movement (driving motion) and
Administrative.
Administrative Function Blocks
Function Block Name Function Block Name
MC_Power MC_ReadAxisError
MC_Reset MC_ReadParameter
MC_TouchProbe MC_ReadBoolParameter
MC_AbortTrigger MC_WriteParameter
MC_ReadStatus MC_WriteBoolParameter
MC_SetPosition
WARNING: During Run Mode Change (RMC), the MC_Power function block should be
disabled, which will power down the axis. Otherwise the axis will remain powered
even if the function block is deleted.
Take note of the following:
• If a new instance of MC_Power accesses the axis, the axis will enter the error
stop state.
• If MC_Power is inside a UDFB and any edit is made to the UDFB that changes the
UDFB template (for example, adding a local variable), the axis will enter the error
stop state.
Movement Function Blocks
Function Block Name Description
Correct Axis State for issuing
Function Block
MC_MoveAbsolute
This function block commands an axis to a
specified absolute position.
Standstill, Discrete Motion,
Continuous Motion
MC_MoveRelative
This function block commands an axis of a
specified distance relative to the actual position
at the time of execution.
Standstill, Discrete Motion,
Continuous Motion
MC_MoveVelocity
This function block commands a never-ending
axis move at a specified velocity.
Standstill, Discrete Motion,
Continuous Motion
MC_Home
This function block commands the axis to
perform the “search home” sequence. The
“Position” input is used to set the absolute
position when reference signal is detected, and
configured Home offset is reached. This function
block completes at “StandStill” if the homing
sequence is successful.
Standstill
MC_Stop
This function block commands an axis stop and
transfers the axis to the state “Stopping”. It
aborts any ongoing function block execution.
While the axis is in state Stopping, no other
function block can perform any motion on the
same axis. After the axis has reached velocity
zero, the Done output is set to TRUE immediately.
The axis remains in the state “Stopping” as long
as Execute is still TRUE or velocity zero is not yet
reached. As soon as “Done” is SET and “Execute”
is FALSE the axis goes to state “StandStill”.
Standstill, Discrete Motion,
Continuous Motion, Homing
To Next Page
Loading...
Need help?
General
