MC_MoveVelocity

Description

This function block performs a single-axis non-ending move at a specified velocity. This type of move can be terminated with the MC_Halt function block or by aborting it with another move.

Consider using the MC_MoveContVel function block. It is more flexible and allows for the continuous update of motion parameters.

MC_MoveVelocity

Figure 7-142: MC_MoveVelocity

Time Diagram

The example below shows the behavior of the combination of a MC_Stop FB with a MC_MoveVelocity FB.

A rotating axis is ramped down with FB2 MC_Stop
The axis rejects motion commands as long as MC_Stop parameter “Execute” = TRUE

FB1 MC_MoveVelocity reports an error indicating the busy MC_Stop command.

MC_MoveVelocity: Timing Diagram

This function block starts a motion-related action and therefore stores data for calculations and error checking. Please see Calling Function Blocks Multiple Times in the Same Cycle if you are using a dual-core controller.

Arguments

For more detail on how inputs and outputs work, refer to PLCopen Function Blocks - General Rules

Input

Execute	Description	Requests to queue the move
	Data type	BOOL
	Range	False, True
	Unit	N/A
	Default	—
Axis	Description	Identifier of a declared instance of the AXIS_REF library function. For more details,see "About Axis Name and Number".
	Data type	AXIS_REF
	Range	[1,256]
	Unit	N/A
	Default	—
Speed	Description	The target axis speed. Direction is specified by the Direction input parameter.
	Data type	LREAL
	Range	Positive values
	Unit	User unit/sec
	Default	—
Acceleration	Description	Trapezoidal: Acceleration rate S-curve: Maximum acceleration
	Data type	LREAL
	Range	Positive values
	Unit	User unit/sec²
	Default	—
Deceleration	Description	Trapezoidal: Deceleration rate S-curve: Unused
	Data type	LREAL
	Range	Positive values
	Unit	User unit/sec²
	Default	—
JerkIn physics, jerk is the rate of change of acceleration; more precisely, the derivative of acceleration with respect to time	Description	Trapezoidal: 0 S-curve: Constant jerkIn physics, jerk is the rate of change of acceleration; more precisely, the derivative of acceleration with respect to time
	Data type	LREAL
	Range	—
	Unit	User unit/sec³
	Default	—
Direction	Description	A 0 or False value specifies that the axis should move in the positive direction. A 1 or True value specifies that the axis should move in the negative direction.
	Data type	SINT
	Range	[0, 1]
	Unit	N/A
	Default	—
BufferMode	Description	The specified buffer mode. For more information see "Buffer Modes".
	Data type	SINT
	Range	MC_BUFFER_MODE_ABORTING MC_BUFFER_MODE_BUFFERED MC_BUFFER_MODE_BLENDING_PREVIOUS MC_BUFFER_MODE_BLENDING_NEXT MC_BUFFER_MODE_BLENDING_LOW MC_BUFFER_MODE_BLENDING_HIGH
	Unit	N/A
	Default	—

Output

InVelocity	Description	Indicates the command velocity has reached the programmed velocity
	Data type	BOOL
Busy	Description	High from the moment the Execute input is one-shot to the time the move is ended
	Data type	BOOL
Active	Description	Indicates this move is the active move
	Data type	BOOL
CommandAborted	Description	Indicates the move was aborted
	Data type	BOOL
Error	Description	Indicates an invalid input was specified or the move was terminated due to an error
	Data type	BOOL
ErrorID	Description	Indicates the error if Error output is set to TRUE. See table in PLCopen Function Block ErrorID Output
	Data type	INT

Example

Structured Text

            (* MC_MoveVelocity ST example *)
            
Inst_MC_MoveVelocity( MovVelReq , Axis1, 200.0, 100.0, 100.0, 0, True, MC_BUFFER_MODE_ABORTING );

Ladder Diagram

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