Incremental position circular interpolation operation with MC_MoveCircularRelative

MC_MoveCircularRelative gives a relative circular interpolation movement command to an axis group. When this motion function block starts, each axis performs circular trajectory interpolation control referring to the auxiliary point input, and the movement direction is determined by PathChoice input. If PathChoice input is set to 0, circular interpolation is operated in a clockwise direction, and if it is set to 1, circular interpolation is operated in a counter-clockwise direction. Specify the relative position of the auxiliary point used when doing circular interpolation of each axis in AuxPoint and EndPoint input arrays.

The array data location corresponds to the Axis ID in the axis group (for example, AuxPoint[0] is for Axis ID 01 in the group).
A maximum of 3 axes can be used in a circular interpolation move.
Refer to Chapter 8.2.8 of the XMC manual for more information about circular interpolation control.
LS_Connect, MC_GroupEnable and MC_GroupPower (or equivalent) must be executed before this function block.
The examples in this topic can be found in the XMC_AxisGroup_FBs.zip downloadable from Example Applications.

MC_MoveCircularRelative Details

Element Name	Element Type	Description
Execute	Input	Edge detected request to execute the function block.
AxesGroup	Input/Output	Set the group to execute the function block on. Group number 1-16. This must be an UINT variable.
CircMode	Input	Specify the circular interpolation method. See CircMode Explanation for more information. 0 = Midpoint 1 = Central point 2 = Radius
AuxPoint	Input	Specify the position of the auxiliary point in a relative coordinate based on the starting position.
EndPoint	Input	Set the circular end point as a relative coordinate based on the starting position.
PathChoice	Input	Circular route selection. 0 = clockwise direction 1 = counter-clockwise direction
Velocity	Input	Specify the maximum speed of the route.
Acceleration	Input	Specify the maximum acceleration.
Deceleration	Input	Specify the maximum deceleration.
Jerk	Input	Specify the change in rate of acceleration/deceleration.
BufferMode	Input	Specify the sequential operation setting. See Buffer Mode table below.
TransitionMode	Input	Not Used.
TransitionParameter	Input	Not Used.
Done	Output	Indicates the completion of the function block execution.
Busy	Output	Indicates the function block is in operation.
Active	Output	Indicates the function block is controlling the group.
CommandAborted	Output	Indicates the function block has been aborted.
Error	Output	Indicates whether an error occurs or not.
ErrorID	Output	Indicates the error number if an error is present.

BufferMode Table

Sections 6.1.4 and 8.2.10 of the XMC user manual provide more information about buffer modes.

Value	Buffer Mode	Description
0	Aborting	Abort previous command and execute the command immediately.
1	Buffered	Execute the command after previous command is completed.
2	BlendingLow	The new command is blended into a previously executed command using the lower velocity value when comparing the previous command and new command.
3	BlendingPrevious	The new command is blended into a previous command using the velocity of the previous command.
4	BlendingNext	The new command is blended into a previous command using the velocity from the new command.
5	BlendingHigh	The new command is blended into a previous command using the higher velocity value when comparing the previous command and new command.

CircMode Explanation

Circular Interpolation Using Midpoint Specification (CircMode = 0)

In this method, the operation starts at the current position and it does circular interpolation through the specified position of the central point to the target position.

In the figure below, the current position corresponds to the axes group coordinate at the start of the command, the midpoint corresponds to the coordinate input for the AuxPoint, and the target position corresponds to the relative coordinate input for the EndPoint.

Circular Interpolation Using Center Point Specification (CircMode = 1)

In this method, the operation starts at the current position, and it does circular interpolation to the target position along the circular path, which has a radius of the distance to the specified central position.

In the figure below, the current position corresponds to the axes group coordinate at the start of the command, the center point corresponds to the coordinate input for the AuxPoint, and the target position corresponds to the relative coordinate input for the EndPoint.

Circular Interpolation using Radius Specification (CircMode = 2)

In this method, the operation starts at the current position, and it does circular interpolation to the target position along the circular path which has a radius of the value specified in the radius.

In the figure below, the current position corresponds to the axes group coordinate at the start of the command, the diameter corresponds to the X coordinate input for the AuxPoint, and the target position corresponds to the relative coordinate input for the EndPoint.