AMS DCB-274 manual Step Resolution, Initial Velocity

ADVANCED MICRO SYSTEMS, INC.				SMC-27X2 SOFTWARE
Command	Function		Type		NV Bytes
H	Set Step Size Resolution		Default, Immediate, Program		2
	Mnemonic	Data 1		Data 2	Result
	(Name) H (n)	0-5		None	None

H (Step Resolution)

This command selects step size resolution. The SMC-27X2 has an internal lookup table of up to 32 bytes corresponding to 1/8 step. This specifies which table is to be used. Each time this command is executed the values are reset to “step 1” and the armature is repositioned to the start phase. Initial and final velocities may require appropriate changes.

The H command sets the phase switching sequence:

				Steps per rev.
	Sequence		H Command	(1.8 deg) Motor)				Remark
	1/8 Micro		H 0	1600		Highest resolution smoothest
	1/4 Micro		H 1	800		Resonance reduced or higher resolution
	Half		H 2	400		High torque - 1 phase on/2 phase on
	Full		H 3	200		Highest torque - 2 phase on
	1/2 Micro		H 4	400		Low torque - half step
	Wave		H 5	200		One phase on - full step
	This command is generally implemented during the initial customer default parameter assignment. However,
	it may be implemented and changed within a program. Following, is an example:
	P 0		Enter program mode.
	H 1		Change the resolution to ¼ step.
	P		Exit program mode.
Command		Function					Type		NV Bytes
	I	Set Initial Velocity					Default, Immediate, Program		3
		Mnemonic			Data 1			Data 2	Result
		(Name) I (n)			SPS (40-36,000)			None	None

I (Initial Velocity)

This parameter sets the initial velocity in steps per second. This is the first speed used at the beginning of acceleration. It must be slow enough that the motor can start without loosing steps (stalling).

As with all velocity parameters, the initial velocity is divided by the divide factor (D). Using the examine (X) command displays updated velocities. The initial velocity applies to:

1.All index commands (+, -, R).

2.First execute in constant velocity.

3.Decelerate to 0 in constant velocity or soft stop.

4.Final phase in home command if home speed is above initial velocity.

See “Default Table” in the beginning of this section.

This command is generally implemented during the initial customer default parameter assignment. However, it may be implemented and changed within a program. Following, is an example:

P 0	Enter program mode.
I 100	Change the initial velocity to 100 SPS.
P	Exit program mode.

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