On Wed, 2007-12-26 at 11:04 +0100, Geert De Pecker wrote: > I probably wrongly assumed that the voltage should come from the KBIC > board. As you say, this would indeed be a flexible solution. Will look > out from such a converter. My controller case is almost full, have to > find some room to put this one in :-) > > Lester Caine wrote: > > Geert De Pecker wrote: > >> Next problem: the analog voltage on the C11 board doesn't go to the max > >> input voltage. I measured the voltage across the sherline potentiometer > >> and it is 9.2 volts. With the bench supply set to 9.2 and attached to > >> the analog voltage of the board, the max output is 8.2 volts. I'll see > >> what is gives when I try ot on the sherline speed control. > >> > >> Otherwise, the output voltage is very linear with the ordered spindle > >> speed. > > > > You will need a higher isolated supply. I use a little 12v to 12V DC > > converter > > to give the isolated supply, and just limit the range of the input. > > Sounds as if you are nearly there though. > > >
The C11 document specifies three power supplies. One computer side +5V, one CNC side +5V @ 2A and One CNC side +12V @ 300mA. I would think if you have satisfied these specifications, you should be okay. 12V should have enough headroom to regulate to 10 V and the VFD should only draw a few milliamperes at worst. Ops I forgot, you are going into the Sherline speed control, so I don't know what it draws. It shouldn't be drawing much anyway. You may want to make sure you are getting at least 22kHz (24kHz - ~10%) into the C11. You could setup HALscope to look at the siggen output and count the rising edges over a time period. If you are running siggen in the servo thread, my guess is that, you will only get into the 2kHz range. With my DAC project, I have just run into "FP needed" errors and computer lockups while trying to run HAL components in the base thread, so I need to learn more about what will run in the base thread. pwmgen will, but I don't know enough to guess at how to make it act like a variable frequency pulse generator. Another thought comes to mind. If you are only getting 2kHz out of siggen then maybe you could step up the frequency with a PLL. I have never used a PLL, but I think this is what they are supposed to do. Ideally, it would be nice to have a pulse generator HAL component. With the proper knowledge, I suppose it would not be too difficult to make, but that is like saying, if I had enough money, I'd be rich. -- Kirk Wallace (California, USA http://www.wallacecompany.com/machine_shop/ Hardinge HNC lathe, Bridgeport mill conversion, doing XY now, Zubal lathe conversion pending) ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
