[SOLVED] Stepperonline VFD Drive  - Page 1
Forum section: electronics / general

author: jpanhalt
author_rank: Super Contributor
timestamp: March 20, 2025, 06:52:58 pm
content: My lathe threading control is progressing slowly.* I am using a Stepperonline EV200 controller. It is wired as shown (i.e., typical 3-wire control where stop is an NC switch).My notes indicate the voltage is 10V DC. I do not know the current. I am thinking of using a small low-side mosfet to effect STOP. Can anyone confirm the control voltage and know the current?John*So many delays and interruptions... I have had reading of the Mitutoyo scale done for 2 years. The program now has entry of a stop point relative to a zero setting, calculation of distance to go, and a stop signal.

author: Kean
author_rank: Unknown
timestamp: March 20, 2025, 07:54:17 pm
content: Manual athttps://www.omc-stepperonline.com/index.php?route=product/product/get_file&file=3070/EV200%20Series%20VFD_Full_Manual.pdfThe digital input details are not well documented in the specs on page 5, but on page 8 it shows the digital inputs you are referring to feed into a set of optoisolators with anodes connected to +12V, and the cathodes connected to the input terminals via resistors. Optoisolators are generally configured by the series resistor for a maximum of 20mA operation, maybe 10-15mA at nominal voltage. You will just need to drive the inputs active low, so almost any NPN transistor or N-Ch MOSFET should be fine. I expect they were designed for control via PLC open collector outputs.Edit: Your note of 10V may have been mix-up with the analog input range, or it could have been a measurement of the optoisolated inputs being 12V less an approx 1.8V drop from the opto IR LED.

author: jpanhalt
author_rank: Super Contributor
timestamp: March 20, 2025, 08:15:01 pm
content: Thanks, my assumption was milliamps. The original manual for that series was quite confusing and did not have the "3-wire" control. I got that design via correspondence, and it is consistent with its other controller series. So far, I am pretty impressed with that controller. Communication could be better, but it has been surprisingly good. The control voltage is analog, but 10V vs. 12V won't make a difference.I am not sure it will stop fast enough, but visually it seems to. It's not quite as fast as disengaging the half-nuts, but doing that will be more complicated. I'm making a 1-3/4" x 8 internal, RH thread and cannot run the spindle in reverse. EDIT: I can run the spindle in reverse but don't want the chuck and workpiece to unscrew in my face.

author: Kean
author_rank: Unknown
timestamp: March 20, 2025, 09:35:28 pm
content: Have you looked at the Clough42 video series for his electronic leadscrew controller?https://www.youtube.com/playlist?list=PLDlWKv7KIIr90ZZ7Zqt-ge5nVVdS3WVggI'm not sure how you plan to synchronise the spindle and leadscrew if using a VFD instead of a stepper to drive the leadscrew. Or is the VFD for the spindle?I don't do enough thread cutting on my lathe to justify implementing something like this.

author: jpanhalt
author_rank: Super Contributor
timestamp: March 20, 2025, 10:07:23 pm
content: Yes, I viewed most of his ELS videos. My lathe has a fairly complete quick change gearbox that covers SAE, imperial, and Whitworth pitches plus others. That ELS might be useful for adding metric to a lathe that is inch. The problem is stopping the lathe and/or disengaging the half-nuts at the end. Clough42 was still using manual disengagement of the half nuts. That gets harder as you get older.This project will either stop the lathe or disengage the half-nuts at a predetermined offset from zero, which will typically be the face or end of what's being threaded, but it can be anything. Remember, with RH threads you are going toward the spindle, and if there's a shoulder, you can have a serious crash. With low-pitch threads, that risk increases with spindle speeds.I am trying to fit a couple of new chucks, and the spindle is Whitworth. Pre-made backplates like that are hard to find.