MC_MoveVelocity

PLCopen motion icon

Function Block A function block groups an algorithm and a set of private data. It has inputs and outputs. - Performs a single-axis, non-ending move at a specified velocity For a group of axes this means: In ACS the velocities of the different axes. In MCS and PCS it provides the velocity of the TCP.

Inputs

Input	Data Type	Range	Unit	Default	Description
Execute	BOOL	FALSE, TRUE	N/A	No default	On the rising edge The transition of a digital signal from low to high. AKA: positive edge., request to queue the move.
Axis	AXIS_REF	1, 256	N/A	No default	Name of a declared instance of the AXIS_REF library function A function calculates a result according to the current value of its inputs. A function has no internal data and is not linked to declared instances.. See Axis Name and Number. See AXIS_REF Structure.
Speed Speed is the absolute value of the velocity without direction.	LREAL	Positive Position means a point in space which is described by different coordinates. Depending on the used system and transformation it can consist of a maximum of six dimensions (coordinates).This means three Cartesian coordinates in space and coordinates for the orientation. In ACS there can be even more than six coordinates. If the same position is described in different coordinate systems the values of the coordinates are different. values.	User unit/sec	No default	The target axis speed. Direction The orientation components of a vector in space. is specified by the Direction input parameter.
Acceleration A change in velocity over time. Because velocity is a vector, it can change in two ways: a change in magnitude and/or a change in direction. In one dimension, acceleration is the rate at which something speeds up or slows down. However, more generally, acceleration is a vector quantity expressing the change with time of the velocity both in magnitude and in direction. See these Wikipedia articles for more information: http://en.wikipedia.org/wiki/Velocity http://en.wikipedia.org/wiki/Euclidean_vector http://en.wikipedia.org/wiki/Rate_(mathematics)	LREAL	Positive values.	User unit/sec²	No default	Trapezoidal: Acceleration rate. S-curve: Maximum acceleration. See S-curve and Trapezoidal Acceleration / Deceleration.
Deceleration	LREAL	Positive values.	User unit/sec²	No default	Trapezoidal: Deceleration rate. S-curve: Unused. See S-curve and Trapezoidal Acceleration / Deceleration.
Jerk In physics, jerk is the rate of change of acceleration. More precisely, the derivative of acceleration with respect to time.	LREAL	No range	User unit/sec³	No default	Trapezoidal: 0 (zero). S-curve: Constant jerk. See S-curve and Trapezoidal Acceleration / Deceleration.
Direction	SINT	0, 1	N/A	No default	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.
BufferMode	SINT	MC_BUFFER_MODE_ABORTING MC_BUFFER_MODE_BUFFERED MC_BUFFER_MODE_BLENDING A way that consecutive function blocks cooperate in the transition from the first to the next._PREVIOUS MC_BUFFER_MODE_BLENDING_NEXT MC_BUFFER_MODE_BLENDING_LOW MC_BUFFER_MODE_BLENDING_HIGH	N/A	No default	The specified buffer mode. See Buffer Modes.

Outputs

Output	Data Type	Range	Unit	Description
InVelocity	BOOL	No range	N/A	Indicates the command velocity has reached the programmed The act of performing a sequence of instructions or commands. velocity.
Busy	BOOL	No range	N/A	High from the moment the Execute input is one-shot to the time the move is ended.
Active	BOOL	No range	N/A	Indicates this move is the Active move.
CommandAborted	BOOL	No range	N/A	Indicates the move was aborted.
Error	BOOL	No range	N/A	Indicates either: An invalid input was specified. The move was terminated due to an error.
ErrorID	INT	No range	N/A	Indicates the error if Error output is TRUE. See PLCopen Function Block ErrorIDs.

Remarks

This function block starts a motion-related action and stores data for calculations and error checking.
See Call Function Blocks Multiple Times in the Same Cycle if using a dual-core controller.

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

This type of move can be terminated with the MC_Halt function block or by aborting it with another move.
See Function Blocks - General Rules about how inputs and outputs work.

Figure 1: MC_MoveVelocity

Time Diagram

These images show two examples of the combination behavior of an MC_Stop FB with a MC_MoveVelocity FB.

A rotating axis is ramped The gradual acceleration and deceleration of a stepping motor. This is essential if performance beyond the start/stop range is required. The slope of the ramp is a function of screw pitch, load, drive voltage and design, and motor. 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.

Figure 2: Time Diagrams: First and Second FBs

Figure 3: Time Diagram

FBD Language Example

Not available.

FFLD Language Example

IL Language Example

Not available.

ST Language Example

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