Acceleration/Deceleration Parameter: AccelType

Description

This function is used to define the acceleration type for the axis.

The acceleration type specifies the shape of the acceleration profile used when changing velocities on an axis. The movement controller provides three major types of acceleration profile:

Rectangular: this acceleration profile changes the velocity in the shortest amount of time. However, it also causes the largest amount of jerks to the axis.
Triangular: this acceleration profile takes the longest period of time to change the velocity (twice as slow as the rectangular acceleration profile). However, it causes the smallest amount of jerk to the axis.
Trapezoidal: The trapezoidal profiles change velocity faster than the triangular but slower than the rectangular acceleration profile. The jerk on an axis is more significant than the triangular but less than the rectangular. There are three choices of trapezoidal acceleration profile, specified by how much longer than the rectangular profile each takes to finish changing the velocity:
- 1.25 times longer than the rectangular profile,
- 1.5 times longer,
- 1.75 times longer.

The acceleration type can be modified at any moment. It will be applied to movements in the queue.

In general, the movement controller processes the commands in the queue ahead (two points along) of where the axis is currently moving to.

NOTE: This is the only way to change the acceleration type of a group of co-ordinated axes. The acceleration type is rectangular by default.

Acceleration codes

The possible acceleration types are as follows:

Code	Type	Description
0	RECTANGULAR_ACCEL	t1 = 0, Tacc = Taccrec
1	TRIANGULAR_ACCEL	Tacc = 2Taccrec
2	ACCEL_TRAP_125	t2 = 3t1, Tacc = 1.25Taccrec
3	ACCEL_TRAP_150	t1 = t2, Tacc = 1.5Taccrec
4	ACCEL_TRAP_175	t1 = 3t2, Tacc = 1.75Taccrec

Associated Functions

The associated functions of this parameter are:

GetAccelType which sends a read request for the actual acceleration type,
SetAccelType which sends a write request for the new acceleration type.

These functions use, according to the language objects, the WRITE_CMD, READ_PARAM or WRITE_PARAM instructions.

Associated Language Objects

The table below presents the different language objects linked to the AccelType parameter.

Object	Name	Function code	Instruction type	Description
%MFr.m.c.40	ACCEL_TYPE	-	READ_PARAM	Read command
%MFr.m.c.40	ACCEL_TYPE	-	WRITE_PARAM	Write command

%MWr.m.c.26	ACTION_CMD	1540	WRITE_CMD	Read command
%MWr.m.c.26	ACTION_CMD	2540	WRITE_CMD	Write command
%MFr.m.c.20	RETURN_CMD_1	-	-	Result of the read.
%MFr.m.c.27	PARAM_CMD_1	-	-	Value to write.
%MWr.m.c.19	ERROR_CMD	-	-	Error report. See (WRITE_CMD Command: Programming Errors)