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MC_MoveContVel

Description

This function block performs a single-axis non-ending move at a specified velocity with the option of continually updating the ongoing motion with the current input parameters. After MC_MoveContVel execution begins (Execute input - low to high), follow up changes to input parameters immediately affect the ongoing motion, without requiring an additional low to high transition on the Execute input.

This type of move can be terminated with the MC_Halt function block or by aborting it with another move.

Figure 11-139: MC_MoveContVel

Time Diagram

The example below shows the behavior of the combination of a MC_Stop function block with a MC_MoveContVel function block.

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_MoveContVel reports an error indicating the busy MC_Stop command.

MC_MoveVelocity: Timing Diagram

Arguments

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 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	—
Velocity	Description	The target axis velocity. Negative values of velocity will move the axis in the negative direction. Positive values will move the axis in the positive direction. A value of 0 is valid and indicates a deceleration to zero velocity.
	Data type	LREAL
	Range	All finite 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	—
ContinuousUpdate	Description	Determines if the inputs of the function block are re-evaluated every cycle or if they are only evaluated on the rising edgeA rising edge is the transition of a digital signal from low to high. It is also called positive edge of Execute. If TRUE when the function block is triggered (on the rising edge of Execute), the function block uses the current updated values of the input variables and apply it to the ongoing movement of the axis. This will continue as long as ContinuousUpdatestays TRUE. The impact of ContinuousUpdate ends as soon as the function block is no longer busy (Busy output is FALSE) or ContinuousUpdate is set to FALSE.
	Data type	BOOL
	Range	False, True
	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_MoveContVel ST"Structured text"
A high-level language that is block structured and syntactically resembles Pascal example *)
Inst_MC_MoveContVel( MovVelReq , Axis1, Vel, 100.0, 100.0, 0, True, MC_BUFFER_MODE_ABORTING );

Freeform Ladder Diagram

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