Newbie- Wanting opinions on this controller.

[CaptKidd]

This is all pretty much over my head at my current knowledge level, so it this sounds ridiculously amateurish, so be it.

I'm considering building a controller called the AVRSTMD. The specifics can be found at http://avrstmd.com/. Firstly, I'm more aware of the AVR family than the PIC family, which seems to be the more popular. Without having any experience whatsoever with any of this, this seems to be a relatively complex controller. I have no steppers so far, but it appears to be adaptable to most of them.

Has anyone ever used this controller? What are your experiences with it if you have used or built it, or what is your opinion of it based on what the link describes? How difficult would it be to set something like this up under EMC2, if at all?

Thanks for any help.

[jschmitt]

I have one. It worked fine and is easy to build. I was running it near the limits on current and volts, so I needed a fan to keep it cool. The two H-bridges are like $12.00 a piece, rather expensive to replace.

Make sure your motor is not too big for it. I believe the limits 3.5A and 48V.

[CaptKidd]

jschmitt,

How many do you have? Are you using just one for one axis?

You're correct about the LMD chips being expensive. That's the only drawback I see in it now, but not having any experience with drive motors is probably going to bite me. I'm not even familiar enough to know what a "chopper" is.

Are you using EMC2 or something else? How difficult is it to set up. There are so many jumperable settings on that board, I'd only guess where to start.

Thanks

[jschmitt]

Originally Posted by CaptKidd jschmitt, How many do you have? Are you using just one for one axis? You're correct about the LMD chips being expensive. That's the only drawback I see in it now, but not having any experience with drive motors is probably going to bite me. I'm not even familiar enough to know what a "chopper" is. Are you using EMC2 or something else? How difficult is it to set up. There are so many jumperable settings on that board, I'd only guess where to start. Thanks

I have 1, I tried to run my motor bipolar serial at max A and just did not get very good rapids-not the boards fault, the motor was mismatched with the board. Yes it only will drive one axis.

A chopper limits current to the motor, by using transistors or mosfets to quickly switch power on and off as current approaches a set level. This way you can raise voltage to the motor without frying the motor. More voltage helps with higher torque at higher speeds.

I am using EMC2. It is not real difficult to set up. The jumper setting are not hard. Print out the page and take your time setting. (I believe his name is Arron) was helpful and patiently answered my questions. If you want to try to solder up a board, this one is pretty easy to do, and it has a test switch so you can test it without a computer so at least you know it works.

[H500]

If you're a newbie, look at the TB6560HQ chip. It's much simpler and does not require a microcontroller to work. Best of all, it's only $5 at digikey and only 1 chip is needed per motor.

[CaptKidd]

H500,

I've already got 6 LMD18245s, but I'll look at that one for the future. I'm going to try and "Eagle"ize the schematic and build my own AVRSTMD boards, so being a rookie at this, I might have to restart my efforts at any time during the process. I'm really on a tight budget for now.

Do you have any references for controllers I could build using this chip?

Thanks

[H500]

Here's a thread on the tb6560.
http://cnczone.com/forums/showthread.php?t=65000

One of my early projects involved the lmd18245. I wired it up on a perf board. It's a decent chip. But it's too expensive and easy to kill. One wrong move and you're out $30 for a set.

[Drools]

I'm using 3 avrstmd controllers (1 per axis). I'm using 280oz NEMA23 motors with a 40VDC unregulated power supply. I have the current limiting set for 2.8a. As well I'm got the microstepping set at 1/10, 20000 steps per in Mach3. I have been running this setup for a few months cutting hard wood, plastic and making PCBs. The motors hardly get warm but I should check the heatsinks on the chips to see if they are getting hot. I'm well within spec for the chip so I'm not too worried about it. Any more questions about them I would be happy to help.