Hi, If you are after closed loop spindle control for a KBIC style treadmill controller a 5Hz PWM signal driving a PWM to analog converter is unlikely to provide a satisfying result. Most close loop control systems use a 1KHz update rate. You may get adequate results with a 100Hz update but 5Hz is too slow.
Further to that, most converters including my DigiSpeeds filter the analog output to smooth the control voltage. Also the KBIC controllers are also doing the same thing resulting in a lag that will be hard to compensate for. That said you can have feedback that will help to maintain a constant speed and correct the speed over a few seconds. Earlier Mach3 version had this capability and it worked quite well. You could see the spindle speed creep up to the set speed over a second or two. When the speed dropped as cutting started, the speed would increase back to the set speed. Cheers, Peter On 16/03/2014 9:23 AM, andy pugh wrote: > On 14 March 2014 20:23, Gene Heskett <[email protected]> wrote: >> So it looks like I need another, but it seems to me there ought to be >> another choice besides this non-linear POS, and the PMDX-106. > > Why are you so obsessed by linearity? I thought you had already > managed to linearise in software? > Alternatively, why not run closed-loop spindle speed, then it doesn't > matter if the control is non linear. > > A further point is that the correct speed isn't a fixed RPM value > anyway, it is that area between "too fast" and "too slow" where the > machining works well. > ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. Written by three acclaimed leaders in the field, this first edition is now available. Download your free book today! http://p.sf.net/sfu/13534_NeoTech _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
