forum.cncdrive.com

Gerry...
I looked them up, they are similar. I have used the EM806 drives on my SideWinder Rotary machine a few years back. Used them on the Teknic 75vdc power supply. Ran at 1/8 step, 5mm screws 8128 /inch. Topped out just under 400ipm around 50kps (may have been WinCNC controller limit in those days)

A few more check for those drives:
Is there a rotary switch? Set to "custom" or "0"?
Was the SW4 autoconfigure done?
SW8 set to "rising edge"?

I'll do some more testing, but it probably won't be until tomorrow.
I know the rotary switch is on "0".
Need to try SW8 in both positions.
I "think" I may have tried the auto config when I first set it up, but it was almost a year ago, and I don't remember. I've been using the Pro Tuner software to configure the drives.

Just a minor follow up.
Gary, I tried playing with switch 8, and it made no difference.

I also checked for lost steps, and it doesn't appear to be losing any. I had the motor spin about 400 revolutions back and forth, several times, and it appeared to return to the same spot. Not very scientific, though.

I also checked with Mach3, and got the same results.

And I also found out that it does the same thing at 400Khz, but at even higher speeds.

And doing some math, I realized that the stepper was spinning at 2400rpm when the issue shows up. with 1/16 microsteps, 12800 steps/unit gives 4 revolutions per unit. With a velocity of 600 units/minute, that would be 2400 rpm. So it actually runs OK to a bit over 2600rpm.
At 400Khz, it works fine to at least 3200 rpm, but had the same issue when set to 4000rpm. I was in a hurry, and was just throwing in some quick numbers.

In actual use, I won't be spinning the motor over maybe 800-900rpm, so it'll be fine.