On 03/15/2016 12:28 AM, Gene Heskett wrote: ... snip
> What type of interface Kirk? A Pico Sys +10 V analog output. I keep thinking it's PWM but it's not. It uses a DAC. > I intend to use a pwmgen, which would update its analog equ at the > servo rate, normally at 1 KHz. If thats a problem, coming out from > zero radius where the first 1/8 would be a pretty large & fast > slowdown, I think I would look at it as a windup in the PID caused > by the 2500 rev limit, and would try to apply the usual suspects > fixes for a windup condition. I've had symptoms of that show up in > my testing speed changes while looking for the best pid response, > and had to reduce the IGain if the speed chnage commands were too > close together in time. ... snip I don't recall running my speed commands though a PID. CSS has a maximum RPM setting which I had to turn down to about 800 RPM to avoid errors before getting the dynamic braking working. A simple MDI or g-code command from 2500 RPM to 300 worked fine and at the VFD's decel setting. I'm guessing that a step from 2500 RPM to 300 RPM is handled differently from having CSS go from a small radius to a large one. My guess was that the difference was the constant stream of speed commands, but the output stream is constant all of the time anyway, which shoots holes in my guess. The VFD may have a noise filter on the analog input that makes the difference. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ ------------------------------------------------------------------------------ Transform Data into Opportunity. Accelerate data analysis in your applications with Intel Data Analytics Acceleration Library. Click to learn more. http://pubads.g.doubleclick.net/gampad/clk?id=278785231&iu=/4140 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
