Benchmill with steppers, missing steps, pulse revs, unable to tune

[Toysrfun]

here is a report. I will follow up in a moment so I can get the cnc offline with more info coming from my phone.

[Toysrfun]

Ok. Here is the build:

Bench mill:

1.) 3x 1600oz Nema 34

2.) 70v toroidal psu

3.) 4kw HuangYang Vfd

4.) 3hp 3400rpm 3ph motor

5.) DM860A drivers

6.) no limit switches attached

7.) estop switch only

[Toysrfun]

Issue is I’ve tried every single dip switch option and nothing functions as it should. I had this same issue on another machine I dumped a year ago and it wouldn’t work with steppers either. My two centroid machines running servos run fine. I tried my backup Mach 3 as usual because it always pulls through and in that software I was able to tune the servos and it appeared to function fine. I can barely push 25ipm slow jog before missed steps as shown in report or any of the other many ways I’ve tried.. Hardware is all brand new and everything tests functional. I have not yet connected limit switches or Vfd. Bench test appeared fine without a load. Not really sure where to go this machine doesn’t deserve the ac servos I have on the shelf. Frankly I’d like to just get it running and kick it out of here at this point.

[Toysrfun]

It would be nice if we had velocity mode and the other features to tune the steppers so I could dial them in. Not sure at this point what else can be done if there isn’t a way to adjust them. Ask the motors are direct drive on x and y and belt driven on the z. It’s a enco rf30

[Toysrfun]

Just to clarify the report is only 1 of 30 ways I tried. I’ve tried every dip switch option on the drives. The problem when you start using 50,000 pulse revs the speed of the motors are slower than snails.

[Gary Campbell]

1) Set the steppers and software to 1600 steps per rev (Leadshine default)
2) Set pulse rate to 100,000
3) Connect to the DB25 header when using stepper drives

[martyscncgarage]

Genuine Leadshine drives? Have you tried connecting them to the DB25 using a DB25 male breakout board? I would try this and not connect to the headers on Acorn. (remember, MACH also used the DB25 port and Acorn's DB25 was designed to mimick that)

The report will not show missed steps.
How are you determining there are missed steps? Can you post a video showing us?
I would set the drive to 2000 and 2000 motor steps per rev in CNC12 as you have it. Leave it there.

Keep in mind, that step/dir signals are just that, whether then go to a stepper driver or a servo drive, it makes no difference.
What does make a difference is how you wire them, (wiring practices), set the drives up (common to all drives).
Just as a general rule, I use shielded cable from Acorn to the drives always and I ground the drain wire back to where the earth ground is terminated. (One point, all grounds and shields terminate here)

Also test with the VFD turned off to make sure there is no interference coming from it.

Just suggestions for you to try.
Marty

[swissi]

Just to clarify the report is only 1 of 30 ways I tried. I’ve tried every dip switch option on the drives. The problem when you start using 50,000 pulse revs the speed of the motors are slower than snails.

I apologize if I got this wrong but I believe the problem here is that you did not understand the proper concept on how to configure the stepper motors in CNC12. It's different than Mach3. The Steps/Revolution that you configure in the CNC12 Wizard need to match the settings on your driver. Fine tuning the exact travel per revolution is done with the "Overall Turn Ratio" in the Wizard which needs to match the actual physical parameters of your lead screw (and gear box if axis is being geared).

You are talking about 50'000 pulses per rev. Let's do a quick calculations here:

Code: Select all

Your Z Axis is geared with a ratio of 17.1 revs/inch
The maximum step frequency of your motor driver is 200kHz = max. 200'000 pulses/sec
200'000/50'000 = 4 which is the maximum revolutions your driver can command per second with a pulse rate of 50'000
With a gear ratio of 17.1/inch and max 4 revs/sec the maximum speed the Z-Axis can move is 14 inch/sec

-swissi