EAS - Embedded Aquisition Systems

[Graham H]

Does anyone have any experience with the EASmicrostep driver. I am considering purchase and would appreciate some input.

Graham H

[fyffe555]

I've built four Microstep drivers from embeddedtronics.com and i'd recommend them even if it was a first time project.

I bought thier bare boards as it was cheaper than ordering or even making them. Nice quality. I got free samples for the pic's from Microchip.com and samples for the LMD18245 from national.com. National sent a bag full..

I had some problems programming the pic's until I built a decent programmer. nothing to do with the code, I did have to change the code available at the time to suit the 628's I used.

There are limitations which are the same with any driver using the LMD, 3a and ~40v might be less power than you'd like, the LMD18245 can be a bit delicate and I'd suggest not using more than 36-40vdc for the motors, never disconnect while powered up. I tried higher voltages and blew a chip, before it went I didn't get any measurable gains over 38v. I'd heatsink the LMD's too. The boards are small and so i'd suggest you mount the boards and the heatsinks seperately.

[Graham H]

Many thanks for the reply.

Bit dissapointed in the voltage limitation given the LMD18245 is supposed to be OK for 55VDC. My intention would be to use a zenner diode to limit the possibility of over voltage. My power supply transformers have a 36 V winding giving an unregulated 52 VDC output. Does sound as if I may have to use some voltage regulation.

Tks

Graham H

[fyffe555]

The 55v is the supply voltage PLUS any back emf the motor might generate. My little Pacsci motors at 40v and 3a in bipolar parallel run up to 1200rpm so i guess there's a bit of emf being produced.

YMMV but I'd say 52vdc is a bit much.

Also note that the draw requirements change rapidly and regulated supplies can cause issues. I've used linear with good result but had problems with a switcher. Depends how you can regulate it..

How's the weather down there? I just put my Brother on a plane for Adelaide..

[Graham H]

Any regulation will be linear, I'll just knock off 10 volts or so using some heavy power transistors.

Adelaide is 1200 miles away so I can't vouch for the weather there. Should be very good this time of year however.

Is there any better course of action you can recommend for Stepper drivers?

My steppers are NEMA 23 with 3A per phase about 220 oz inch and 1.1 ohm windings, I currently run Unipolar but will use Bipolar if I go with the EAS drivers.

Graham H

[fyffe555]

For Stepper driver's you've found the Picmicro solution, there's another by the name of PicStep from a countryman of your's; http://www.fromorbit.com/projects/picstep/. Similar to EAs and has had a lot of development.

There's various good well executed designs provided by Phil (pminmo as he posts here on the cnczone) at; http://pminmo.com/ Phil has put a huge amount of effort into designing and usually testing this stuff together with putting it on the web for free and I don't think he get's enough credit for it..

Other than that you're into commercial Gecko and Rutex territory and what ever you can buy locally from Ebay..

HTH

Andrew

[Graham H]

Hi Andrew,

Many thanks for the leads. I now feel a lot more confident with the directions I am taking.

Graham H

[ASLANOZ]

Hi all,
I just joined to your community, and i am little bit dummy. Nowadays trying to build picstep v4.0 but confused between picstep and EAS. Do anyone supply me
the photo of PCB of EAS driver with both sides? one of my friends has ordered but not came yet (there are some custom problems I think)thats why I didnt order it yet.