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Ger21
14-04-2017, 03:31 AM
My analog voltage is steady, but my frequency is very far from steady.
Anyone else seen this?
https://www.youtube.com/watch?v=1uozboD9EpE

routercnc
14-04-2017, 07:16 PM
My analog voltage is steady, but my frequency is very far from steady.
Anyone else seen this?
https://www.youtube.com/watch?v=1uozboD9EpE

Hi Gerry
Do you mean via an externally generated voltage, or from a voltage provided by the VFD? I'm using the 10V internal voltage via a manually set pot and has been ok for a few years.
Maybe your pot is a bit scratchy and the signal you measure with meter is smoothed out but the VFD is seeing the rapid fluctuations?
If it is an external supply then maybe wire up a pot direct to see if that is steady?
Edit
Sorry just noticed you tube link. Will view video first !

m_c
14-04-2017, 08:49 PM
I'd be inclined to put a scope on the output, as it could be some kind of harmonic/sampling/filtering issue that a multimeter won't pick up on.

I've not got a manual handy, but are there any filtering options for the analog input on those VFDs?
And I'm guessing there is no option to show the analog input voltage on the VFD?

Ger21
14-04-2017, 09:17 PM
No, and no.
I'm going to try a few things today, and see if I can get it more stable.

m_c
14-04-2017, 09:26 PM
I was thinking a small capacitor across the input terminals, but a electrolytic may not be good enough if it's a high frequency noise/harmonic problem. However it would be a simple thing to try if you have a small electrolytic capacitor about.

The best thing would be to put a scope over the input terminals to see if it is a noise problem, as without seeing what's going on, it's pure guesswork.

Doesn't UCNC support Modbus?

Ger21
14-04-2017, 11:35 PM
Thanks for the response.
No, I don't have a scope, or an capacitors either.
It's actually probably good enough for a wood router, but I'll have to wait until I can cut something to know for sure.

I was really just wondering if anyone else has tried controlling these with an analog signal? I'm curious if all of these Huanyang VFD's suffer from this issue?
I found one other post with the same issue on the Mach3 forum, but it had no replies.

These Huanyang VFD's use a non standard modbus implementation, so you can't control them with Modbus. But someone did write a UCCNC plugin, that supposedly works very well.
Since my breakout board has the speed control already there, I set it up that way first.

I'll be ordering an RS485 converter, and testing with the plugin when it comes in.
Thanks again.

JAZZCNC
16-04-2017, 10:56 AM
Gerry, I've fitted well over 100 Huanyang VFD's using analog and while do get some flutter it's nothing like what you are seeing. I'd be inclined to think like MC that it's noise issue so check cabling etc.

Ger21
16-04-2017, 01:47 PM
Thanks Dean, that's the info I was looking for.

I don't have any shielded cable handy right now. But I did make up a new spindle cable with twisted wires (It's only 12" long), and I grounded the spindle, as it wasn't grounded in the video. But it didn't make any difference.
It just seems to me that I'd see a change in the analog voltage, with a 25-30Hz swing in the frequency?

Since this is just a test, I'll revisit it later when I actually build the control box.

I've got an RS485 converter being delivered today, and will try the UCCNC Huanyang "modbus" plugin. It only cost me $7.

Ger21
16-04-2017, 05:15 PM
I just tested with the UCCNC plugin, and speed control with that method is perfect.
I guess that there's not really any downside to using the plugin/modbus, as the cost is only $7?

https://youtu.be/jmdV3Y_ffyo

Doddy
16-04-2017, 07:38 PM
I guess that there's not really any downside to using the plugin/modbus, as the cost is only $7?
https://youtu.be/jmdV3Y_ffyo

That was my conclusion. I've since re-wired with an Ethernet controller rather than a parallel BoB - reverting to analogue control and, to be honest, I'm inclined to re-instate the modbus for speed control.