96 Rockwell Automation Publication 2080-UM002L-EN-E - November 2021
Chapter 7 Motion Control
Motion Direction
For distance (position) motion, with the target position defined (absolute or
relative), the direction input is ignored.
For velocity motion, direction input value can be positive (1), current (0) or
negative (-1). For any other value, only the sign (whether positive or negative) is
considered and defines whether the direction is positive or negative. This
means that if the product of velocity and direction is -3, then direction type is
negative.
Axis Elements and Data Types
Axis_Ref Data Type
Axis_Ref is a data structure that contains information on a motion axis. It is
used as an input and output variable in all motion function blocks. One
axis_ref instance is created automatically in the Connected Components
Workbench software when the user adds one motion axis to the configuration.
The user can monitor this variable in controller debug mode through the
software when the motion engine is active, or in the user application as part of
user logic. It can also be monitored remotely through various communication
channels.
MC_MoveVelocity Supported Direction Types
Direction Type
Value Used
(1)
(1) Data type: short integer.
Direction Description
Positive direction 1
Specific for motion/rotation direction.
Also called clockwise direction for rotation motion.
Current direction 0
Current direction instructs the axis to continue its motion with
new input parameters, without direction change.
The direction type is valid only when the axis is moving and the
MC_MoveVelocity is called.
Negative direction -1
Specific for motion/rotation direction.
Also referred to as counter-clockwise direction for rotation
motion.
Data Elements for Axis_Ref
Element Name Data Type Description
Axis_ID UINT8
The logic axis ID automatically assigned by the Connected Components
Workbench software. This parameter cannot be edited or viewed by user.
ErrorFlag UINT8 Indicates whether an error is present in the axis.
AxisHomed UINT8
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 will be cleared.
ConsVelFlag UINT8
Indicates whether the axis is in constant velocity movement or not. Stationary
axis is not considered to be in constant velocity.
AccFlag UINT8 Indicates whether the axis is in an accelerating movement or not.
DecFlag UINT8 Indicates whether the axis is in a decelerating movement or not.
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