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Author Topic: VFD Spindle control 0 to 10V (not -10 to +10V)  (Read 17567 times)

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Offline kcrouch

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Re: VFD Spindle control 0 to 10V (not -10 to +10V)
« Reply #20 on: March 05, 2012, 04:22:32 PM »
Sorry, but the Galil does not provide for that feature. You would need an additional axis to provide that function. You could add a RIO and use the analog output on that, but I think that another Axis would be cheaper.
Having way too much fun! Something must surely be wrong.
Re: VFD Spindle control 0 to 10V (not -10 to +10V)
« Reply #21 on: March 05, 2012, 04:30:03 PM »
Thank you for the reply,

I have purchased a used dmc-1830 that I can resell, but having manual speed control with a POT on a manual toochange machine is not too bad a thing.

Another thought though, could one write a script that outputs a binary coded decimal on some output pins for the S speed code?  One could have a DAC to read those pins and output the 0-10v for the vfd.

Mark

Offline kcrouch

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Re: VFD Spindle control 0 to 10V (not -10 to +10V)
« Reply #22 on: March 05, 2012, 05:10:18 PM »
Yes, you could, but I would rather have the outputs available for other uses. You could possibly use 4 of them along with a digital to analog chip, but you would still need to isolate the converter and its ground from the VSD. I have let lots of smoke out that way.
Having way too much fun! Something must surely be wrong.
Re: VFD Spindle control 0 to 10V (not -10 to +10V)
« Reply #23 on: March 05, 2012, 05:19:41 PM »
Yes, smoke is not good when we have an expensive card like the galil!

I'll set up the wiring as though I have an 1840 card and keep my eye open for a good deal.

I am using an ACtech vfd, made next door in CT., and I think it has a serial control feature.  Maybe I can make use of that?

Thank you for your help.  If I make progress on this front I'll post it.

Mark
Re: VFD Spindle control 0 to 10V (not -10 to +10V)
« Reply #24 on: March 05, 2012, 07:31:54 PM »
ACtech show isolated I/O this may also apply to the 0-10v Analogue input, I have found  many VFD's have isolated input. It is easy to test.
Nosmo.
 
Re: VFD Spindle control 0 to 10V (not -10 to +10V)
« Reply #25 on: March 06, 2012, 08:42:47 AM »
I read the ACtech manual last night and didn't see a reference to isolated inputs but I suspect that they may be.  I did drive the 0-10v input directly with an Ah-ha if16 motion card with no issues.  To check for isolation should I test for line voltage on the inputs with respect to chassis ground?  Also, the serial link in the ACtech drive is for the optional keypad so a no-go there.

Modbus is an option.  I need to find out if anyone has used modbus for i/o and spindle control while using dmc-18x0 for motion.

Mark
Re: VFD Spindle control 0 to 10V (not -10 to +10V)
« Reply #26 on: March 06, 2012, 10:33:59 AM »
First check with resistance  meter with power off from common terminal to either side of the power in and to ground.
Next, power up and  check ac voltage from any terminal to earth ground, you may see a reading with a high impedance meter, if you do see an odd reading, use a 1k -2k resistor from the terminal to ground, if the voltage collapses or reduces then it can be assumed that the voltage was due to leakage, reduce resistor value as necessary.
This test will tell if there is leakage that supports any kind of current.
I saw the mention of isolated I/O in one of the ACLenz description bulletins.
Nosmo.