CMC_SInterPolation (FB)

FUNCTION_BLOCK CMC_SInterPolation

The function block can be used for a simple point-to-point interpolation.

It can be combined with the function block CMC_SIPosiLoop as position control loop.

The function block allows to create a very simple, basic axis for linear movement. The function block can be either used independent to create a basic axis with/without position control loop or it can be used in combination with PLCopen function blocks.

The function block creates a positioning interpolation towards TargetPosition and uses the given velocity and acceleration values. The function block has to be used within the real-time cycle. The result is given to output Position. The TargetPosition and also Velocity and Acceleration can be changed anytime and will be used at once. With Enable = FALSE, the function block sets the output Position to ActualPosition, this is similar to an open loop.

Behavior of inputs

Enable	Stop	Behavior
FALSE	x	Output Position = ActualPosition
TRUE	FALSE	Interpolates output Position to reach TargetPosition with the given velocity and acceleration.
TRUE	TRUE	Ramps down to velocity = 0.

Behavior of outputs

InSync	Active	Behavior
FALSE	TRUE	Function block is activated, position and velocity is not yet reached.
TRUE	FALSE	Function block is activated, position is reached, output Position = TargetPosition.
FALSE	TRUE	Function block is either disabled or stopped, velocity

Different use cases for this block

Use in Combination with MC_MoveByExternalReference

A positioning axis can be created with modifying the parameters for positioning “on the fly”, without the need of a certain statemachine to follow.

Use to Create a Simple, basic positioning Axis

A very basic, simple positioning axis can be created by using this blokc without the PLCopen blocks.

Be aware that there is not additional check if the axis really follows, also no scaling for the position is included.

If function block CMC_SIPosiLoop is used, it will check for position or velocity following error.

Note

This block has to be called within the REAL-TIME task

InOut:

Scope	Name	Type	Initial	Comment
Input	Enable	BOOL		Level triggered, Enables the interpolation
	Stop	BOOL		Stop, level triggered, interpolate down to velocity = 0
	TargetPosition	LREAL		[u] Target position
	ActualPosition	LREAL		[u] Actual position
	Velocity	LREAL	1	[u/s] Value of the maximum velocity (not necessarily reached). Range: >0
	Acceleration	LREAL	1	[u/s^2]Value of the acceleration and deceleration. Range: >0
	Cycle	LREAL	10	[ms] Cycle time of the PLC program.
Output	Position	LREAL		[u] New absolute position
	InSync	BOOL		Position reached TargetPosition
	Active	BOOL		Interpolation active