[Katoh]

G'day Friends
Nearing the end of my lathe conversion, and now simply going through and configuring Mach3 and checking wiring ect. I have come across an annoying problem that I can't just get to work. The vfd is controlled through its In/outs directly through Mach. Mach runs through a Peter Homman BOB and from there goes to one of Peter's DC03 Digispeed controllers.
Now all is well on that side, relays work and we have 0-10v output voltage going to VFD. I can control On/Off Forward and reverse but for some reason I can not get the VFD to recognize 0-10v variable input to control speed. I can re-program the VFD and control speed manually but not through mach.
Ive tried nearly every setting I can think off to no avail.
Has anyone got any suggestions?
The VFD is a cheaper Chinese job same as the one shown here.
VARIABLE FREQUENCY DRIVE INVERTER VFD NEW 2HP 1.5KW 7A | eBay
Cheers
Katoh

[neilw20]

Can you post a link to the manual or the manual?

[Al_The_Man]

Looks like the typical Huanyang?
http://www.jinlantrade.com/ebay/invertermanual.pdf
There are not the best out there!.
Al.

[neilw20]

Control voltage to V0 and VI
Jumper J1 jumpered 1-2 (disconnects internal pot I guess)
That's assuming I read the correct manual section 2 and you have all the parameters set correctly.

Looks like it was the jumper. :cheers:

[Al_The_Man]

Does the 0-10v input voltage actually vary when issuing an a S value?
Al.

[Katoh]

G'Day Friends
Many thanks for your inputs, Solved the problem this morning. On the VFD near the terminal strip is a little jumper that was set to VR all I did was set it to VI and like magic all worked, all other parameters were spot on the money.
Thanks to all.
Cheers
Katoh

[Katoh]

Gentlemen
Hate to do this but I've put my foot in my again!
Never had a VFD that caused me so much headache, I finally as posted got it running but now I'm getting erratic feedback through my control wires, not at every setting. Using 0-10v input for speed control, anything over 3v works fine but under it varies between 2-3 volts. Switch the spindle off or disconnect the motor and it works like a charm, I have the whole range.
My first thoughts were noise but all my cables are shielded and grounded to one common point on one side only. I'm using a Homman BOB and a Homman Digispeed DC03, its not the first one Ive built but the first one to have this problem.
Any Ideas?
Please.
Thanks
Katoh

[neilw20]

Katoh,

Post some pictures of your setup and wiring and we will SEE if we can help.

[Katoh]

Ill post some Photos in the morning, just got me buggered. There's like a separate 2 volt input after that motor starts but not an accumulative one, anything over 3 volt input is correct just under that it buggers up.
I wonder if I disconnect the 10v from the vfd to the digispeed and use a separate 12v input back to the digispeed if it would make a difference? I suppose one other thing I could try is to buy a new cable and replace the control cable I'm using now, in case it has a leak in somewhere, you never know stranger things have happened.
Cheers
Katoh

[neilw20]

Read the digispeed manual closely. It is good. I have used one. (but was DC06)
You are best to use an isolated output. You can power the digispeed OUTPUT from the 10v on the VFD. That is the right way to do it.
Put JP1 in the AV+ position,
AV+ goes to VFD 10v terminal.
Vout goes to VI. AGnd goes to VFD - ACM. The ONLY connection to ACM.
Then you only get max 9.5v, but you can change the gain setting in the VFD so 5v is full speed.
To fix that set parameter PD070 to 1 (was 0 = 10v) so input is 5v for full speed.
Then adjust output range of DC03 to be 0 to 5v for full speed.
Set PWM freq in Mach3 as per DC03 specs. (50Hz)
Doing this way should give 100% isolation and you should get zero speed if Mach3 min PWM is set to 0%.
Reality is you won't get it perfect, but it will be so close it doesn't matter.

[Katoh]

What you have describe is what I have done taken 10v from the vfd to the dc03, then bought it back to the VI and the ACM. My max is only 8.9v not a problem as I only want to increase speed by 100% or 100hz and have a minimum of 15hz. All works absolutely spot on with of course the vfd on, and the commands coming from mach. But when you get the motor turning it introduces this 2-3v into the system, anything higher than 3v back to the vfd works fine. so from speed range 0-100% anything over 30% sweet as, below that forget it, and it pulses I also noticed.
Here is a couple of pics, the vfd cabinet and the control cabinet.

[neilw20]

Try lifting the earthwire off the VFD wiring shield. Is it earthed both ends?
Try one end only.
Is signal cable to the VFD shielded. Connect shield at one end only.
It is VERY important that no current can flow in the shield.
Is the PWM set to 50Hz? If too low it will become erratic.

edit:
The LONG 25 way LPT cable looped around like a transform!! Hang the cable outside the box and see what happens.
It IS going to get lots of rubbish induced in it from the mains cables.
When the motor is running slowly it will be cycle skipping and might make more noise.

[Katoh]

Thanks for the input!
All cables are shielded and earthed at one side only. I am starting to believe that the BOB is creating a problem. There are two BOb's on the machine one is just input's the other outputs, now the digispeed works, but I cannot get the Steppers moving, at all!. Cant even get a twinkle out of them. Starting to think something sinister has happening.
I built a huge router years ago, never had a hiccup with it this ones just giving me the poo's. Mind you on the router I used an AC lenze VFD. (very nice unit)
May have to buy another bob and come back to this, lathes no good unless you can get it to move.
Thanks
Katoh

[Katoh]

G'Day Colleagues
To start with my Stepper problem has being solved, the results of that are not relevant to this thread, so that's all I will say on that matter, but it had nothing to do with the VFD or components.
The Issue of the floating or mysterious extra voltage comes from the VFD itself. As the saying goes you get what you pay-for, but there is a working and a very good way around this.
I was contemplating being cruel and leaving it at that, saying problem fixed thanks for your help!:bat:
But no if anyone has the problem, this is the fix.
Firstly disregard the 10v input from the VFD, use a separate stable 12v supply, most cnc's have to have both a 5 and 12 to run BOB's, cooling Fans leds ect. If you use a computer power supply it will have many a spare 12v outlets you can run off. I personally prefer to run these power outlets of a Buss Bar. Run the 12v into the digispeed in replace of the 10v from the VFD, you must also run the neg side to the digispeed also. From the VFD use a shielded cable to connect the ACM and VI to the digispeed as per usual.
At the digispeed you will notice both the ACM and the Neg side of the 12v supply are connected as one. Also this is important! you need to put a capacitor between the 12v and the the ACM/Neg where they enter the digispeed. Calibrate, 0- 10v with the trimpot.
Done:cheers:

Katoh