12v --> 10v Nowforever D100S2R2B inverter & MKS-V-V02 CDXHCTECH board

[Doddy]

Okay, had a quick look at the data sheets for both the inverter and the controller. OP is quite correct - the controller expects to be supplied a 10V supply from (e.g.) inverter, and will presumably generate a 0-Vref for the spindle speed. What is needed is to reduce the 12V reference voltage to 10V. A simple way to do this would be to place 3 silicon diodes in series with the 12V output from the spindle.

+12 -------->|------>|------>|------------- +10V In

Diodes 1N4001, or similar would be good enough and cost pennies each.

You could put a LM317 regulator inline - with 2V difference between Vin and Vout, it should manage well enough, but it's probably a sledgehammer to crack a nut.

There is also a AO1 analogue output on the inverter, range 0-10V, but I can't figure out a way to use this to generate a constant 10V output.

[Neale]

I would go for the diode solution as well. Even if you buy from Maplin, they're still cheap enough and it's a better solution than resistors. Tweak the calibration as also suggested here (if needed - give or take a few per cent, spindle speed isn't that important) and job's done.

[magicniner]

A fixed 2 Volt drop may be acceptable for the OP's requirements and that's an elegant solution if such is the case, I had Tunnel Vision on an output proportional to the input,

- Nick

[Doddy]

I'm impressed with the inverter - the manual claims the electrolytic caps within are "wearing parts" and must be replaced after 5 years.

At least they're honest.

[Clive S]

Great minds think alike

http://www.cnczone.com/forums/chines...52398-cnc.html

[magicniner]

I'm impressed with the inverter - the manual claims the electrolytic caps within are "wearing parts" and must be replaced after 5 years.

At least they're honest.

That's interesting, I have a couple of 1hp Siemens VFDs which are well over 10 years old and get daily use, standards must be slipping ;-)

[Neale]

That's interesting, I have a couple of 1hp Siemens VFDs which are well over 10 years old and get daily use, standards must be slipping ;-)

...or Siemens don't push the limits quite as much as the Chinese? I seem to remember that the HY manual says that you need to re-form the electrolytics if the inverter isn't used for a year, and you should use a variable voltage supply and work up to full voltage slowly. My guess is that daily use is actually better for the caps than letting the thing stand unused for long periods. I try to use 105degC caps for high-power applications rather than the cheaper 70degC versions - maybe Siemens do as well!

[EddyCurrent]

The reason I suggested changing the parameters is this;

The manual for a Nowforever E100 shows that it uses 12v for the 0-10 input.
The graph shown in the first post of this thread shows that speed error gets worse as the frequency increases.
It suggests to me that the upper frequency setting should be adjusted so that at maximum input voltage to Analogue Input 1, the frequency was such that spindle speed was correct.

Regarding diodes, we used to use this method on reversing roller tables to give a central dead band for the operators, but on some of the newer drives this did not work as planned.

[Doddy]

The reason I suggested changing the parameters is this;

The manual for a Nowforever E100 shows that it uses 12v for the 0-10 input.
The graph shown in the first post of this thread shows that speed error gets worse as the frequency increases.
It suggests to me that the upper frequency setting should be adjusted so that at maximum input voltage to Analogue Input 1, the frequency was such that spindle speed was correct.

Regarding diodes, we used to use this method on reversing roller tables to give a central dead band for the operators, but on some of the newer drives this did not work as planned.

My interpretation of the E100 manual is that - yes - it provides a 12V supply to the speed controller but that the AI1 input still remains expecting a value from 0-10V from 0-100% RPM. That's pretty much backed off with the graph that the OP provided (full RPM at 20000dmd/24000full x 12V(ref) = 10V). Reading the manual the value for the AI1 input is programmable from 0..10V, but not beyond. There is a gain setting that can be applied also, but I'd expect, again, that requires that the AI1 input is limited to 10V. My concern is that the response to the AI1 input will be limited at 10V, and so no amount of scaling applied by the controller in the VFD would counter this.

Of course, remote interpretation of a Chinglish manual is never an exact science.

Ref the diodes / roller table - I guess you're using the forward bias of the diode to generate a dead-band around the pot's central position?, nice idea (strange that modern machines didn't work with that - be interesting to look at the input characteristics of the modern machines - maybe super hi-z could cause some unexpected results. In the OP's case though - driving the interface board down through 3 silicon diodes should generate a reasonably steady voltage drop somewhere around the 2V region.