MC_AccelerationProfile (FB)

FUNCTION_BLOCK MC_AccelerationProfile

This function block commands a time-acceleration locked motion profile.

Note

Alternatively to this function block, the CAM function block coupled to a virtual master can be used.

Example of an acceleration profile

A profile is made from a number of sequential “A to B” positioning points. It is simple to visualize, but requires a lot of sequences for a smooth profile. These requirements are often beyond the capability of low-end servos. Alternatively, by using a modest amount of constant acceleration segments it is possible to define a well-matching motion profile. With this method the capability range of low-end servos can be extended. It is possible to make matching to either:

1. Position versus time profile

2. Master versus slave axis

Advantages

• Compact description of a profile.

• Smooth profile properties by nature.

• Low processor power requirements.

Disadvantages

• Higher programming abstraction level with existing tools.

Acceleration profile, 10 segments only

Resulting position profile

Note

MC_TProfile is an ABB specific datatype.

Note

When Done = TRUE (profile is completed), Axis will run with the last Velocity value.

InOut:

Scope	Name	Type	Initial	Comment
Input	Execute	BOOL		Starts the function block at rising edge
	TimeScale	LREAL	1	Overall time scaling factor of the profile. Range: >0
	AccelerationScale	LREAL	1	Scale factor for acceleration amplitude. Range: AccelerationScale <> 0
	Offset	LREAL	0	Overall offset for profile, the profile result will be increased by Offset
	Number_Of_Pairs	INT		Number of sampling points, elements in TimeAcceleration array. Range: >=2
	iType	MC_ABB_iTypes_Enum		Type of interpolation. Possible values are: MCA_SPLINE_COMPLETE MCA_SPLINE_NATURAL MCA_POLY5 MCA_POLY3 MCA_LINEAR
	TimeAcceleration	POINTER TO MC_TProfile		Reference to Time / Acceleration
	BufferMode	MC_BufferMode		Not supported, default mcABORTING used
Output	Done	BOOL		Shows the status of the function block. Done = TRUE if the execution is finished
	Busy	BOOL		The function block is not finished
	Active	BOOL		Indicates that the function block has control on the axis
	CommandAborted	BOOL		Command is aborted by another command from other PLCopen function block
	Error	BOOL		Signals that error has occurred within function block
	ErrorID	ERROR_ID		Error identification. For error details refer to Enumeration ERROR_ID
Inout	Axis	Axis_Ref		Reference to axis