Re: [CAD_CAM_EDM_DRO] Phase vs. Step/Dir?

On Sun, 24 Aug 2003 12:10:37 -0600, you wrote:

>Harvey,
>
>I disagree with your answer. To me step and direction deals or phase
>deals with the logic level signaling to the drives. What you are
>explaining is the power level signals to the motors. In phase signaling
>you have 4 logic level signals to the drive with each one controlling a
>drive transistor or MOSFET directly. With step and direction you have 2
>logic signals to the drive and the drive has some intelligents to
>interpret the step and direction signals and convert them to the 4
>signals needed to drive the transistors or MOSFETS.

I was thinking of the mode controls on the L297 chip, which allow wave
drive/half step, etc. Those lines can account for the extra lines
going to the driver board.

You are correct in stating that there are drivers that have one line
per motor phase... I was not thinking of those drivers.

Sorry for the confusion.

Harvey

>
>You are correct that there are various drive methods for a stepper
>motor, but that is a different thing than the signaling method to the
>drive.
>
>Tim
>[Denver, CO]
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>
>> -----Original Message-----
>> >I think I understand what Step/Dir is. There is a signal for the
>> >direction, and the "step" part of it is what gets pulsed to actually
>> >move the stepper. Correct?
>> >
>> >So can someone explain what "phase" is? I get the impression it's a
>> >different scheme to drive a stepper but that's my only clue.
>>
>> Various drive schemes...
>>
>> one is the 1 2 3 4 1 2 3 4 phase sequence, which is called
>> "wave drive" or "full step".
>>
>> another is
>>
>> 1 12 2 23 3 34 4 41 1..... Which is called half stepping.
>> See if you can find the specs on the L297 and 298 chips, and
>> migrate to the app notes for these chips... Gives you a good
>> idea of what the chips will do, as well as the fundamentals
>> of driving steppers. They're made by ST microelectronics.
>>
>> Harvey
>
>