Gene Heskett wrote: > On Tuesday 30 April 2013 12:52:04 jeremy youngs did opine: > > >> gene >> this is what jon offers and i am salivating over :) >> http://pico-systems.com/osc2.5/catalog/product_info.php?products_id=26 >> > > I can see why, but two things: The minimum PWM freq of 25khz, and the 12 > volt enable. > > I don't have any 12 volts in my boxes that isn't busy running fans. And > LCNC can't make a PWM at 25KHZ. Best it could do, on an atom board, would > be a 12.5 khz square wave. So I'd have to put some other card into there > to generate that high a repetition rate pulse. The 4 channel universal at > $250, while no doubt nice, is too much for my toy budget. > The 12 V is the logic supply, and it only takes 100 mA at the most. The 25 KHz is not strict, but the output filter won't work well at low frequencies. At the higher voltages there is a tradeoff between high frequency and high ripple current in the output heating up the filter inductors and the motor windings. But, trying to generate PWM by software is pretty tough. My PWM controller has 25 ns resolution on the pulse width. It doesn't make sense for just a spindle, but if you are going to run several servo axes with it, it is at least a better deal.
Jon ------------------------------------------------------------------------------ Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with <2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
