stepper drivers, Compumotor 6200 indexer

Hello:

1) On the topic of higher current stepper drivers, ST has a 'fully
protected' 14 A H-bridge IC (for bipolar operation), VN771P. It's not a
single-chip solution, and unfortunately for casual builders, it only comes
in 28 pin surface mount package. VN770P is the 9A version. You need two for
a 2-phase motor, and need the "front
end" circuitry as well. I'm looking into what parts will accomplish
microstepping chopper control along with this chip, when I have time. As
(one of the) Doug(s) implied, higher voltage drives give higher speed/torque
characteristics, and these IC's unfortunately are rated only for up to 26 V
operation.


2) I bought a Compumotor 6200 2 axis indexer on eBay. It don't think it
falls into the groove with most of you using G-code with software as an
indexer, but if anyone does have a use for one, the guy has 7, and to my
knowledge sold 3 so far. Prices were approximately $335, 201, 223.

I just got manuals for it, and I can't believe how sophisticated it is,
compared to my plan to build a PIC or BASIC program. It has it's own program
language/operating system, RS-232 interface, encoder interface, limit switch
interface and 24 programmable inputs and 24 programmable outputs.

I think I will be able to test the RSF linear encoder I picked up by
writing a little program to display encoder count status, eliminating my
project of building a DRO just to test the encoder.

If anyone wants to keep an eye out for one, the seller on is Chris Whiteside
(I think his user name is CJWhiteside).

Murray