Re: [CAD_CAM_EDM_DRO] I'm curious

yahoo@... wrote:

>Why don't I see more CNC guys putting together drive system from major
>manufacturers.
>I've been watching this group for the last month and looking in the archives
>it seems like this hobby is stuck in the late 70's.
>
>I've looked at these "Gecko" type drivers they sell to drive Bi/Uni polar
>motors at best half step for $150 and up, and all this is purely amateur
>hour stuff.
>
>Ridiculous! Seriously this seems really crazy to me. Why on earth would I
>drive several hundreds if not thousands of pound worth of machinery moving
>at high speeds with pulses from a parallel port and using DOS no less.
>When you can talk to an professional industrial grade indexer via serial or
>device driver and run it under Windows or Linux if you must. These indexers
>are very intelligent and handle all the I/O, Encoders, drivers, backlash,
>deadband, linked moves, curve interpolation, limit monitoring, and more.
>
>I just did a quick search for Compumotor products (my personal favorite) and
>here what I found today;
>
>A pair of 50000 Microstep Stepper Drivers starting at $19 with $180 buy it
>now
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7532426297
>or other microstepper drivers (Zetas 4 are great)
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7530904583
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7530594973
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7530907082
>Paired up with any S 57 or 83 series motor
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7532121199 $25 (low
>torque)
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7531200682 $24 (low)
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7530594904 $10 (high
>400oz)
>slap some $40 US Digital 2000 line encoders on these and it a closed loop at
>8000 ppr.
>
>
>Servo Drivers?
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7532283428 $75
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7531003102 $23
>Pair it up with these motors;
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7532283649 $45
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7531512855 $35
>
>I see PC-23 and 6000 series indexers for sale for a few hundred all the
>time.
>
>There's a 6K2 with an Expansion i/o module for $780 but that's a bit high.
>
>There are also TWO whole 4 axis system starting at $1000 with indexer,
>drivers, motors!
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7532416649
>
>Whew! Glad I got that off my chest... Guess the reaming is next :)
>
>

Why? Because every one of these units is different! If you don't use
step/direction from the parallel port, then you need a driver custom written
for each drive, because all the commercial stuff is proprietary.
I know that Yaskawa servo pack drives of the SGDP series (P for
positioning) can be set to take step & direction. Those are nice drives,
but quite expensive, even used.

Also, if you've been reading this list for a while, you will know that some
companies give absolutely abominable support to people who have older
equipment. (Others go WAY beyond what is reasonable, too, and I thank them
profusely!) Yaskawa has all the docs on their old drives on the web, but
try to find docs on old Allen-Bradley gear, for instance.

Jon