Allen-Bradley Micro800

Motion control instructions Chapter 17
Rockwell Automation Publication 2080-RM001D-EN-E - February 2015 443
AXIS_REF data type
The AXIS_REF data type is a data structure that contains information for a
motion axis. It is used as an input and output variable in all motion control
function blocks. An instance of an AXIS_REF data type is automatically created
when you add a motion axis to the configuration.
Parameter Data type Description
Axis_ID AXIS_REF The logic axis ID automatically assigned by Connected Components Workbench. It cannot be edited or viewed by
user.
Error Flag BOOL Indicates whether an error is present in the axis.
AxisHomed BOOL Indicates whether homing operation is successfully executed for the axis or not.
When the user tries to redo homing for an axis with AxisHomed already set (homing performed successfully),
and the result is not successful, the AxisHomed status is cleared.
ConstVel BOOL
Indicates whether the axis is in Constant Velocity movement or not. Stationary axis is not considered in Constant
Velocity.
AccFlag BOOL Indicates whether the axis is in an Accelerating movement or not.
DecelFlag BOOL Indicates whether the axis is in an Decelerating movement or not.
AxisState USINT Indicates the current state of the axis.
ErrorID UINT Indicates the cause for axis error when error is indicated by ErrorFlag. This error usually results from motion
control function block execution failure.
ExtraData UINT Reserved.
TargetPos REAL Indicates the final target position of the axis for MoveAbsolute and MoveRelative function blocks.
For MoveVelocity, Stop, and Halt function blocks, TargetPos is 0 except when the TargetPos set by previous
position function blocks is not cleared.
CommandPos REAL During motion, this is the current position the controller commands the axis to take. There may be a slight delay
between the axis actual position and this CommandPos.
TargetVel REAL The maximum target velocity instructed to the axis for a moving function block. The value of TargetVel in
current function block, or smaller than it, depending on the other parameters in the same function block.
CommandVel REAL During motion, this element indicates the current velocity the controller instructs the axis to use.
Note that there may be a slight difference between the axis actual velocity and CommandVel, due to the drive
delay or drive adjustment overshoot.
Important:
Once an axis is flagged with and error, and the error ID is not zero, the axis must be reset using MC_Reset before issuing any other movement function block.