Centroid Community CNC Support Forum

Unless I am missing something Shawn, the drawing still shows the Potentiometer as completing the circuit between P12 and GND.

Nigelo wrote: ↑Mon Sep 02, 2024 10:31 am Unless I am missing something Shawn, the drawing still shows the Potentiometer as completing the circuit between P12 and GND.

Hi Nigel, yes, you are correct and I think that is there to illustrate the "internal" circuit in the VFD that allows speed control from the pot on the VFD. Since there is no call out or specs for the variable resistor and of course there's nothing wired to P12 when you open the VFD that it's clear that nothing wires to that input.

You can see from the drawing that it uses a different control input, P12. He's not wiring anything to P12 from the Acorn per all the Acorn generic schematics and his current revised schematic. I think most VFD drawings illustrate this circuit but since we are not using that input for anything it'll get ignored. At least this is how I interpret it. Many of the VFD manuals I see have this variable resistor circuit drawn in just to illustrate how it's working.

I'm hoping that I made it clear enough that the Acorn wires only to COM and AI1 and that's how he has it drawn in his most recent drawing but thanks for pointing this out. I just ignore that illustration as I know it's not used that way but not everyone may understand this so again, thank you.

If Tuffduck is still confused we'll straighten him out. After all, he is Canadian.

Thanks for all of your help Shawn!

tuffduck wrote: ↑Mon Sep 02, 2024 3:12 pm Thanks for all of your help Shawn!

No problem, let us know if you get it working or have more questions.

Hi, I have the VFD all wired up and I had to change the spindle voltage to 5V and when I tested it with my volt meter I get 12V, Is there a way to force this to 10V? Thanks

Show us how you have it wired and what your multimeter is hooked to. When you test the analog out on Acorn there can be nothing else hooked to the output but your meter. You cannot have the VFD and multimeter hooked up at the same time. We dont have enough info to help you. There should be no reason to have to set the output to 5v. Add pics to your google album so we can see what you are doing.

In the spindle bench test, you have to test without anything connected.

I am using 10V and never got more than 10.08V wich is within the tolerance of my Multimeter.

Uwe

Today, I pulled all the covers off and stared. I changed spindle settings in the wizard back with the 5V option off. It is actually Al2 thatwas giving of 12V and not Al1. So got that far. The way the drawing is and the way the actual terminals are a liitle different. I switched the 2 COM wires around because everything else was correct and now it works. The only thing is that the VFD show 210Hz instead of 200Hz for 12000 rpm. Should I be concerned with this? Thanks