Author Topic: VFD RPM control wiht Pokey57CNC 1-10V output does not propperly work  (Read 231 times)

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Offline exflueger

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Hello
Everything on the setup is working fine including. Hoever, one big problem is unsolved so far.
Maybe you can help me for this (Mach3, Pokeys57CNC, Fuling inverter DZB215DK)

The Pokeys57CNC will allow me to turn on/off the spindle with Mach3 via OC1 on the Pokeys which works fine. It also outputs exactly up to 10v on the 0-10V socket when not connected to the VFD. Looks good. Also masured at the VFD, as long as the VFD is not powered on. No shorts in the cables. Everything is fully shielded. The cable to the VFD is a LAN cable, twisted pair, each pair shielded and the whole cable shielded. Plus a Ferite at the end. So unlikely a noise problem.

Now: When connected to my VFD and after the VFD is turned on it will automatically draw almost 8V from the board (without an M3 command). The 10V shrink immediately to about 1V

I can't get an acurate speed on the spindle. When running can't get a speed over 8'330 rpm when set at 18000k. When it runs at this speed i measure 4.8V at the VI (PWM) input

The board is connected via VI and iGND. Pokey config according to Page 26 of the Polabs Mach3 plugin manual. Mach 3 is set to PWM control.

It's like the VFD is drawing in voltage, it's as if it needs a standard xxV then needs to be 'topped up' by the board. Every measurement I take from the board is several volts lower than the expected as soon as the VFD is powered on.

I've checked the board several times when not connected to a VFD and the output is as you'd expect at 0/12/24k rpm.

I have no clue where to search any longer.

I really appreciate any hint whre to search.

Offline TPS

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Re: VFD RPM control wiht Pokey57CNC 1-10V output does not propperly work
« Reply #1 on: December 21, 2018, 03:09:25 AM »
no sure i foud the right Manual, but the one i found is talking about a
analog Input select Switch for 0-10V and 4-20mA.

anything is possible, just try it.
if you find some mistakes, in my bad bavarian english,they are yours.

Offline exflueger

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Re: VFD RPM control wiht Pokey57CNC 1-10V output does not propperly work
« Reply #2 on: December 21, 2018, 07:17:12 AM »
Hello
Thank you very much (Danke vielmals) that you even serched for a manual. My Version of the Inverter has a dedicated VI for 1-10V voltage input and a separate CI input. So no switch. The noise redcution (Ferrite and Capacity  as shown on the Diagram I have implemented as well).

Offline TPS

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Re: VFD RPM control wiht Pokey57CNC 1-10V output does not propperly work
« Reply #3 on: December 21, 2018, 07:56:31 AM »
for a test would be good to connect a potentiometer (10k) to tha analog Input
and measure the voltage there.
anything is possible, just try it.
if you find some mistakes, in my bad bavarian english,they are yours.

Offline exflueger

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Re: VFD RPM control wiht Pokey57CNC 1-10V output does not propperly work
« Reply #4 on: December 21, 2018, 09:14:09 AM »
Thsi is what I did first to find out if it is an Inverter problem. Worsk perfectly, 0-10V at 0.5mA. Thsi way the spindle rotates zero to full RPM nicely.

Offline exflueger

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Re: VFD RPM control wiht Pokey57CNC 1-10V output does not propperly work
« Reply #5 on: December 21, 2018, 09:54:44 AM »
Now I also did a test by directly 'infusing' 0-12V from my Lab power supply into the Inverter to VI and DCM.
Works also like a charm.


Offline TPS

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Re: VFD RPM control wiht Pokey57CNC 1-10V output does not propperly work
« Reply #6 on: December 21, 2018, 03:19:20 PM »
ok sounds like you have all 'basic' tests allready done.
maybe you can give me some more detailed Information about your wiring,
just  to confirm. (ok i know that is "i know every better mode")
all that sounds like a grounding (0V) Problem.

TPS
« Last Edit: December 21, 2018, 03:22:09 PM by TPS »
anything is possible, just try it.
if you find some mistakes, in my bad bavarian english,they are yours.

Offline exflueger

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Re: VFD RPM control wiht Pokey57CNC 1-10V output does not propperly work
« Reply #7 on: December 25, 2018, 02:34:46 AM »
If somebody has the same problem, here the solution:
I did several experiments meanwhile and also went back to the idea that the Inverter infuses to much noise down the lines. So I tried the Ferritering again. But this time with two really big Ferrite Tubes and a large amount of windings and put them separate to both lines, one per line (Vi and iGND). And I added a Capacitor with 10uF between Vi and iGND.
It became much better. Not perfect but much better. So this was the right trace to follow.
So I did the XXL hard core version of it (see Pic's).
Two really big ferrites, lots of windings and, very important: a 0.022uF Capacitor between iGND and 0-10V output.
With all this it now works 100% OK

Thank you TPS for the coaching!

Offline rodm717

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Re: VFD RPM control wiht Pokey57CNC 1-10V output does not propperly work
« Reply #8 on: December 25, 2018, 05:57:41 AM »
Nice! I see you are also using the postep60-256 drivers as well. might wannt to tie those twisted lines off before your fan eats em' ;)

Offline exflueger

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Re: VFD RPM control wiht Pokey57CNC 1-10V output does not propperly work
« Reply #9 on: December 25, 2018, 08:19:08 AM »
Hi
This was just the test-setup. Now all is nicely fixed, no food for the Fan.  :-)