jhuang@ccnysci.UUCP (Jian Huang) (09/08/89)
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. Thanks. --
jack@csccat.UUCP (Jack Hudler) (09/12/89)
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
inc@tc.fluke.COM (Gary Benson) (09/14/89)
In article <3301@csccat.UUCP> jack@csccat.UUCP (Jack Hudler) writes: >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 That's what I thought, too. Jiang, why don't you tell us the application? I cannot answer your question about a controller chip, but daisy-wheel printers use fairly highspeed steppers for printwheel and carriage motion as well as the platen indexing. Not 500 rps, but pretty quick, and at least in the case of printwheel positioning, they have a similar requirement to yours regarding changing parameters on the fly. As soon as a character is printed, the motor has to move to a new one by the quickest route. As I recall, (it's been almost 6 years since I worked with these things), both Qume and Diablo printers used discrete control logic, but when Ricoh entered the market, they used an 8085 to control all printer functions. If your requirements are as stringent as they seem, maybe a microprocessor is really what you're looking for. _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_- This is news program fodder. It contains no message content. Who made up the sutpid rule that a followup had to be longer than the quoted material? This is news program fodder. It contains no message content. Who made up the sutpid rule that a followup had to be longer than the quoted material? This is news program fodder. It contains no message content. Who made up the sutpid rule that a followup had to be longer than the quoted material? This is news program fodder. It contains no message content. Who made up the sutpid rule that a followup had to be longer than the quoted material? This is news program fodder. It contains no message content. Who made up the sutpid rule that a followup had to be longer than the quoted material? This is news program fodder. It contains no message content. Who made up the sutpid rule that a followup had to be longer than the quoted material? This is news program fodder. It contains no message content. Who made up the sutpid rule that a followup had to be longer than the quoted material? This is news program fodder. It contains no message content. Who made up the sutpid rule that a followup had to be longer than the quoted material? This is news program fodder. It contains no message content. Who made up the sutpid rule that a followup had to be longer than the quoted material? This is news program fodder. It contains no message content. Who made up the sutpid rule that a followup had to be longer than the quoted material? -_-_-_-_-_-_-_-_-_- end of fodder. I hate stupid programs _-_-_-_-_-_- -- GaryBenson_-inc@tc.fluke.COM-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_ -_-_-_-_-_-_-_-_-_-_-_-_-_-_-Tell the girls to slice the ham thin -J.C. Penney
jhuang@ccnysci.UUCP (Jian Huang) (09/16/89)
you are right. i am using micro-stepping mode. we are making stepper controllers for our precise positioning systems. our next goal is to have higher speed and complex contour motion. microprocessor does not have enough speed to deal with every pulse if it is used in pulse generation. PLL may be a possible way to do it. it seems difficult any way. --