Relative Positioning with MC_MoveRelative

MC_MoveRelative is used to move an axis to a position relative to its current position. This function block will move the axis into DiscreteMotion state. MC_MoveRelative can be executed without the axis being homed.

  • A positive distance value will move in the forward direction.

  • A negative distance value will move in the negative direction.

  • LS_Connect and MC_Power must be executed before this function block can be used.

  • The examples in this topic can be found in the XMC_SingleAxis_FBs.zip downloadable from Example Applications.

Element Name Element Type Description
Execute Input Edge detected request to execute the function block.
Axis Input/Output Axis reference variable. This can not be a constant.
ContinuousUpdate Input Specify the update setting of the input value. This is explained in section 6.1.5 of the XMC user manual.
Distance Input Specify the target distance to move.
Velocity Input Specify the maximum speed of the move.
Acceleration Input Specify the acceleration of the move.
Deceleration Input Specify the deceleration of the move.
Jerk Input Specify the change rate of acceleration and deceleration.
BufferMode Input Specify the sequential operation setting. See BufferMode table below.
Done Output Indicates the function block completed successfully.
Busy Output Indicates the function block is currently being executed.
Active Output Indicates the function block is controlling the axis.
CommandAborted Output Indicates the function block was aborted.
Error Output Indicates whether an error occurs or not.
ErrorID Output Error Identification number.

 

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.

//Set axis reference

Axis1 := 1;

 

IF (_AX01_RDY) AND (_AX01_SV_ON) THEN

//Example of MC_MoveRelative

INST_MOVERELATIVE(Execute:=Execute_MoveRelative, Axis:=Axis1,

ContinuousUpdate:=0, Distance:=INST_MOVERELATIVE.Distance, Velocity:=INST_MOVERELATIVE.Velocity,

Acceleration:=INST_MOVERELATIVE.Acceleration,

Deceleration:=INST_MOVERELATIVE.Deceleration,

Jerk:=INST_MOVERELATIVE.Jerk, BufferMode:=0,

ErrorID=>INST_MOVERELATIVE.ErrorID);

END_IF;

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LM510