Fuling DZB VFD causing GR214V to trigger unexpected steps (RESOLVED)

[tblough]

It is just few wires including 4 wires to stepper drivers, VFD common, HomeAll, and eStop.

If that is the case, where are all of the shield wires connected? There should be a whole lot more than "just a few".

[Eric]

@tblough
Oh, right and thank you for the correction! You can see some of them sticking out next to the wire nut. As I’ve mentioned previously, I took them out of the wire nut at the time I took the picture. So, sorry for the confusion and they’re there!

[ShawnM]

I just thought it is quite odd that the issue appears only when I connect VFD and felt like a some type of grounding issue than noise. Of course I could be wrong and as you can see I’m switching them out one by one.

As for the fan, it suck air on one side and blows on the other side. I hope this is not related to this issue. If it turns out to be then will be resolved with metal enclosure. Thanks!

Regards,
Eric

The "noise" from the VFD is because of improper grounding and filtering. Noise and grounding go hand in hand. The VFD will emit EMI (along with other issues from the spindle motor itself) when it's running. If you dont have proper shielded and grounded wiring on all necessary signal wires you will have the issues you have.

There's a right way and a wrong way to add a fan to an electrical enclosure. The fan needs to be pushing cool, clean (filtered) air INTO the enclosure and the outlet vent which should be at the top 1/3 of the cabinet somewhere will exhaust the hot air generated in the cabinet.

[Eric]

@ShawnM
I agree with you and that was my best educated guess as well. The odd thing was that the issue happens when VFD is not running and in my case it was mounted far away from the controller. However, I finally figured it out and below is what happened. Also, I will definitely correct the fan direction to pressurize the cabinet the dissipate the heat and thank you for pointing that out!

UPDATE
Apologies for the long post, but I’ll try to go through the process of how I figured it out and what I did in case anybody faces the same issue.

As ShawnM mentioned, it is either ground loop or noise as they go hand in hand. Therefore, I wanted to isolate the issue to determine which one is the main cause. So, I started with assuming ground loop. The only possible path for ground loop is that the Acorn 25V and 5V power supply AC and DC grounds are tied together at the power supply for safety reasons and I’m running a separate 60V power supply which its ground is not tied together with the Acorn power supply. When current flows it follows the least resistant path so that it runs in loop. Thus, I’ve tried plugging the 60V to a completely separate AC circuit, but had no luck.

Now, my guess at this point is that it is likely a noise driven issue. I came across this video before and been thinking to install ferrite ring accordingly on my step/direction signal.



After doing bit of research, I did install them on each of my step/direction signal wires, but the issue was still observed occasionally. Since the issue happens when VFD is connected, I’ve changed the VFD idle display to show the voltage that it is getting from the Acorn 0-10V output. I noticed that the voltage is fluctuating 0.01-0.02V on the VFD display and it seemed like the issue happens when the fluctuation is observed. So, I’ve installed ferrite ring on 0-10V analog power and ground wires separately. As soon as I installed them the VFD display shows 0.00V whish is supposed to and the issue was gone. Just to be sure, I’ve left my machine just before the limit switches for a long time and it didn’t move at all.

In conclusion, I think the VFD feeds back high frequency noise when it is connected. The reason is that the Fuling documentation recommends to use VFD output filter before the load and I’m not using them as it is quite troublesome to find the right one. So, after all this high frequency noise can be filtered using ferrite ring, but you’ll still shorten your spindle bearing life nevertheless. Now my machine became dead quiet and I can almost certainly say that it also reliable at this point.

Long story short and to ShawnM’s point, you never should buy a cheap parts or cut corners to cause yourself a headache as in my case I wasn’t wiring the VFD according to the recommendation. Finally, I’ve installed extra ferrite rings just before the VFD on 0-10V line to be sure. I hope this helps and thank you so much everyone for your responses, cuz it helped me a lot to stimulate my thoughts and track down this issue.

Regards,
Eric

[cnckeith]

i moved this post into the Acorn Forum