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andypugh wrote:

They all do. This much I know, and a few other things about PWM choppers besides

Those Polou "drives" are better named chip carriers. They're missing a few essential components to make them useful in a CNC setup.

Rick G wrote:
The band called and you're out



But seriously now I have tried to find out what their current is set at. I don't think it is their biggest issue, I do believe it is a factor though.

According to what I read, I have turned the VREF POT to .6V, so that the current should be 1.5A.

Also when you say to increase the base period max jitter setting, how high should I set it to?

CptanPanic wrote:
Not the jitter. You should be OK with what you set. These numbers are in the section above jitter. It is labeled "Driver characteristics:" In your first post you said you have your Direction Hold/Setup = 200000 Maybe I'm reading the data sheet for your driver wrong but it seems to say to me that it only needs 200 ns which is pretty fast? Your time and space set at 1,000 are right at the driver minimums. So just for laughs maybe double those and see how they work? Your best step time and space are likely going to be either where they are now or somewhat higher. But drop that Direction Hold/Setup down because it looks way off to me. Although honestly Allegro saying it is 200ns doesn't sound quite right either. I think there you're just going to have to try different values and see what works best. I'm getting all of these numbers from Allegro's data sheet for the IC in your driver BTW. All of this is in Figure 1. Some interpretation of numbers in "Figure 1." has to go into "Driver characteristics:"

You never measured the current your driver is drawing? If you have a multimeter with a 10 amps scale you should be able to hook it up and verify if your 0.6 Vref is giving you your expected 1.5 amps.

All of this configuring can be a bit of a pain but once you're dialed in you should be OK.

pfred1 wrote:
It is worth noting that you only ever reverse the motors at zero speed, so there isn't anything to be gained from shaving down those numbers.

But yeah looking at the data sheet again, I didn't notice that the setup/hold time were in ns, so yeah I was 1000 off. But I guess you are saying these don't matter. I will increase the timing on the time/space, and also really measure the current. And let you guys know.
Thanks.