On Fri, 12 Jul 2013, propcoder wrote: > Date: Fri, 12 Jul 2013 19:41:22 +0300 > From: propcoder <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: [email protected] > Subject: [Emc-users] 5V PWM to +-10V analog converter circuit > > Maybe someone knows where to find tested and working schematics? > > I need to control five Yaskawa Sigma-5 servo drives. I am planning to control > them in velocity mode, analog input (zero-centered, max +-12V) with LinuxCNC > + MESA 5i23 using higher frequency PWMs. > Strange thing is that I can't find +-12V power supply terminals which would > be useful for such converter. I am about ordering small DC-DC converter 24V > to -9V, +9V: > http://www.farnell.com/datasheets/1707820.pdf > > I found schematics of PWM to analog converter which uses two digital > optocouplers. 5V PWM signal isolated and transfered to +-10V PWM and filtered > by RC circuit. I like this idea, but can't find the page anymore. I started > to draw it by myself (picture attached). I understand I would need faster > optocouplers. Any recommendations? > > > Optos will be fine for spindle control, but for servo axis control they will be rather iffy
for example the quoted ACPL P480 will cause noticeble linearity and dead zone issues if a high enough PWM rate is used (it has 250 ns worst case pulse width distortion, for a 5I23 with its 96 MHz PWM base clock, thats ~25 PWM clock cycles: more than 1/2% dead zone) The other issue is that for Axis drives you need good bandwidth and low ripple, this basically means pushing the PWM frequency up as high as you can (bad for optos) and multipole filters to get the best compromise of response time and ripple. Peter Wallace Mesa Electronics ------------------------------------------------------------------------------ See everything from the browser to the database with AppDynamics Get end-to-end visibility with application monitoring from AppDynamics Isolate bottlenecks and diagnose root cause in seconds. Start your free trial of AppDynamics Pro today! http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
