Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!brutus.cs.uiuc.edu!usc!apple!sun-barr!texsun!csccat!jack
From: jack@csccat.UUCP (Jack Hudler)
Newsgroups: sci.electronics
Subject: Re: chip for step motor control
Keywords: help
Message-ID: <3301@csccat.UUCP>
Date: 11 Sep 89 17:15:51 GMT
References: <2968@ccnysci.UUCP>
Reply-To: jack@csccat.UUCP (Jack Hudler)
Organization: Computer Support Corporation. Dallas,Texas
Lines: 25

In article <2968@ccnysci.UUCP> jhuang@ccnysci.UUCP (Jian Huang) writes:
>I am looking for a stepper control chip. There are some
>good chips for DC motor such as National LM628, but only a
>few step motor control chips which can not meet my
>requirement: 100k pulse rate, changing parameters
>(speed, target position) on the fly. I would appreciate if
>anyone can give me some help.

100k pulse rate into a 200 step motor would yield 500 rps, unless you
intend to use microstepping translators you could not attain such 
high rate of speed from steppers. 
However I assume you are using micro-steppers. 
If you are using micro-steppers then you know the cost of doing so,
so you could spend some more and buy an indexer that would meet your
needs, after all they spent big bucks developing stepper controllers,
why re-invent the wheel?
I have use one from Compu-Motor, it's the PC23 (for IBM PC/XT-AT),
it can produce 500k pps and with 3 axes,encoders,joy stick and limit
switchs, all for $2000. 

Hmmm.. changing speed and target on the fly.... sounds like your trying
to control a telescope.. :-)
-- 
Jack 		Computer Support Corportion		Dallas,Texas 
Hudler		UUCP: {texsun,texbell,attctc}!csccat!jack