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Author Topic: spindle speed, strange fault  (Read 3227 times)

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spindle speed, strange fault
« on: December 06, 2009, 08:02:30 AM »
hi guys, got a wierd one here but it may be so simple it'll be embarrasing, lol.

I've just setup the analogue board in my novamill to run from mach3, and the speeds are in reverse. It's at slow revs when i input high speeds and high when i input slow speeds. I've checked and changed everything i can think of, but knowing my luck it's a combination of two or more functions to reverse this.

Any ideas guys.
Re: spindle speed, strange fault
« Reply #1 on: December 06, 2009, 05:16:38 PM »
to give you an idea of the speeds related to the analogue output.

1000 rpm 9v
2000 rpm 6v
3000 rpm 4v
4000 rpm 2v

voltages are approximate.

Offline Hood

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Re: spindle speed, strange fault
« Reply #2 on: December 06, 2009, 05:24:13 PM »
Is that the voltage with the commanded speed or is that the voltage at the true speed?
If the latter then it would seem your VFD is backwards, maybe a parameter in it?
If its the former then afraid you will have to wait for someone who knows about the  use of VFDs and Mach as I have only ever used Servos as spindle with Mach control.

Hood
Re: spindle speed, strange fault
« Reply #3 on: December 06, 2009, 05:44:34 PM »
the voltage is correct to the actual spindle speed, it's the command that seems to be backward (2v is low speed and to get this, the command is m3 s4000). I've used a 10k pot to vary the speed which works fine.
Re: spindle speed, strange fault
« Reply #4 on: December 08, 2009, 10:14:01 AM »
You could build a quick small circuit with LM741 OP AMP to invert your signal....

JH
Re: spindle speed, strange fault
« Reply #5 on: December 08, 2009, 10:43:50 AM »
i have the schematic for the analogue board if that helps, but i'm not sure how to load it here.
Re: spindle speed, strange fault
« Reply #6 on: March 21, 2010, 10:30:24 AM »
Forgot to post the conclusion on this guys.

Eventually i changed the original Denford analogue board for an aftermarket board and everything is fine.

It seems that the digital signal from Denfords original board is the opposite to the Mach3 signal.

Thanks for everyones help.