Perform a Circular Move

Circular moves can be programmed using absolute or relative positions using the following function blocks:

• MC_MoveCircAbs which commands interpolated circular movement on an axes group to the specified absolute positions.
• MC_MoveCircRel which commands interpolated circular movement on an axes group to the specified relative positions.

Prior to performing any coordinated moves, some setup is needed.

• See Create a Linear or Circular Coordinated Motion Application.
• Once these steps have been performed, a circular move can be performed.

In these examples, two circular moves are performed:

• Absolute Circular Move
• Relative Circular Move

Absolute Circular Move

In this move, an absolute circular move goes from (0, 0) to (90, 90).

• CircMode specifies that the aux point (0, 180) is crossed during the paths start to end.
• Call MC_MoveCircAbs.

PosCircAuxAbs[0] :=   0;   // A point on the circle that is crossed on the
PosCircAuxAbs[1] := 180;   // path from start to end point.
PosCircEndAbs[0] :=  90;   // Absolute end point.
PosCircEndAbs[1] :=  90;

Inst_MC_MoveCircAbs(TRUE, Group1_ref, CIRC_MODE_BORDER, PosCircAuxAbs, PosCircEndAbs, CIRC_PATH_CLKWISE, MaxVel, MaxAcc, MaxDec, 0, CS_ACS, BM_BUFFERED, TM_NONE, TransParam);

In the example, a circular move is performed on axis group Group1_ref.

• CircMode is defined as CIRC_MODE_BORDER.
  • This mode indicates that the AuxPoint array input indicates a point on the circle which is crossed on the path from the starting point to the end point.
  • See Circular Moves Diagrams about CircMode movement options.
• The AuxPoint array, PosCircAuxAbs, defines an absolute point on the circle which is crossed on the path from the starting point to the end point.
  • The contents of this array are determined by the CircMode variable CIRC_MODE_BORDER.
• The EndPoint array, PosCircEndAbs, contains the absolute end point for each axis in the group.
  • The absolute end point of the axis stored in position 0 (IdentInGroup) of the group is 90.0.
  • The absolute end point of the axis stored in position 1 of the group is 90.0.
• PathChoice is only relevant when CircMode is set to CIRC_MODE_CENTER.
  • In this case, this parameter is not used.
• The maximum velocity is specified by variable MaxVel and is specified in User unit/sec.
• The maximum acceleration and deceleration are specified by variables MaxAcc and MaxDec and are specified in User unit/sec².
• The maximum jerk is not supported and can be set to a value of 0.
• The coordinate system is ACS.
• The BufferMode is set to BM_BUFFERED, indicating the move is buffered. 
  • See Buffer Modes.
• The TransitionMode is set to TM_NONE, indicating no transition mode is used.
  • See Transition Between Moves.
• The TransParam array is required.
  • The contents can be set to 0 because the transition mode is not being used.
  • The TransParam array is a 2-element array containing the corner distance and velocity for the transition.

Relative Circular Move

This is a relative circular move whose end point is (90, 90) from the end of the first move.

• CircMode specifies that the aux point (0, 90) is the relative center of the circle.
• The BufferMode input is set to Buffered; this move waits for the first move to complete before it begins executing.
• Call MC_MoveCircRel.

PosCircAuxRel[0] :=  0;   // Relative center of the circle.
PosCircAuxRel[1] := 90;
PosCircEndRel[0] := 90;   // Relative end point.
PosCircEndRel[1] := 90;   // Start pt 90,90 + rel 90,90 -> 180,180 absolute end pt

Inst_MC_MoveCircRel(TRUE, Group1_ref, CIRC_MODE_CENTER, PosCircAuxRel, PosCircEndRel, CIRC_PATH_CLKWISE, MaxVel, MaxAcc, MaxDec, 0, CS_ACS, BM_BUFFERED, TM_NONE, TransParam);

In the example, all the variables have the same meaning as the circular absolute example except:

• CircMode is defined as CIRC_MODE_CENTER.
  • This mode indicates that the AuxPoint array input indicates the center point of the circle.
  • See Circular Moves Diagrams about CircMode movement options.
• The AuxPoint array, PosCircAuxRel, defines the relative center point of the circle.
  • The contents of this array are determined by the CircMode variable, CIRC_MODE_CENTER.
• The EndPoint array, PosCircEndRel, contains the relative end point for each axis in the group.
  • The relative end point of the axis stored in position 0 (IdentInGroup) of the group is 90.0.
  • The relative end point of the axis stored in position 1 of the group will be 90.0.
• PathChoice is relevant when CircMode is set to CIRC_MODE_CENTER.
  • In this case, PathChoice is CIRC_PATH_CLKWISE which specifies the direction of the path.