MC_MoveContVel

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 with the option of continually updating the ongoing motion with the current input parameters.

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 Modify PLCopen Axis for more information. See AXIS_REF Structure.
Velocity	LREAL	All finite values.	User unit/sec	No default	The target axis velocity. Negative values of velocity move the axis in the negative direction The orientation components of a vector in space.. 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 move the axis in the positive direction. A value of 0 (zero) is valid. 0 (zero) indicates a deceleration to zero velocity.
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.
ContinuousUpdate	BOOL	FALSE, TRUE	N/A	No default	Determines if the inputs of the function block are re-evaluated every cycle or if they are only evaluated on the rising 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 continues as long as ContinuousUpdate stays 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.
BufferMode	SINT	See Description	N/A	No default	The specified buffer mode. MC_BUFFER_MODE_ABORTING = 0 = Abort MC_BUFFER_MODE_BUFFERED = 1 = Buffered MC_BUFFER_MODE_BLENDING A way that consecutive function blocks cooperate in the transition from the first to the next._PREVIOUS = 2 = Blending Previous MC_BUFFER_MODE_BLENDING_NEXT = 3 = Blending Next MC_BUFFER_MODE_BLENDING_LOW = 4 = Blending Low MC_BUFFER_MODE_BLENDING_HIGH = 5 = Blending High See Buffer Modes.

Outputs

Output	Data Type	Range	Unit	Description
InVelocity	BOOL	FALSE, TRUE	N/A	Indicates the command velocity has reached the programmed The act of performing a sequence of instructions or commands. velocity.
Busy	BOOL	FALSE, TRUE	N/A	High from the moment the Execute input goes high until the time the move is ended.
Active	BOOL	FALSE, TRUE	N/A	Indicates this move is the Active move.
CommandAborted	BOOL	FALSE, TRUE	N/A	Indicates the move was aborted.
Error	BOOL	FALSE, TRUE	N/A	Indicates either: An invalid input was specified. The move was terminated due to an error.
ErrorID	INT	-32768 to +32767	N/A	Indicates the error if Error output is TRUE. See PLCopen Function Block ErrorIDs.

Remarks

This function or function block returns cached data.
See Program a Multi-Core Controller.

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.

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 1: MC_MoveContVel

Time Diagram

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

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_MoveContVel 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_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 );