----- Original Message ----- From: "John Kasunich" <[EMAIL PROTECTED]> To: "Enhanced Machine Controller (EMC)" <[email protected]> Sent: Sunday, July 29, 2007 10:14 AM Subject: Re: [Emc-users] More on Spindle Control
<snip> >> The bottom line of what I want is to be able to change speeds with >> the S >> command and the drive not kick out when decelerating. > > Doesn't the drive itself have accel and decel rate limits? Yes, right now the decel is set on 3 seconds. This works fine in the 4 lowest gears but sometimes kicks out in 5th gear and almost always in 6th gear, depending on how many Hz I'm running. >> Is there some difficulty >> with running the spindle closed loop that I'm not aware of? > > I'd be concerned about the granularity in the speed feedback. Can't > say how bad it would be without real numbers to work with. What is > your > spindle encoder PPR? What is the desired speed range? I get 2000 counts per revolution on the spindle(1000 line encoder running at 1/2 the spindle speed). Desired speed range perhaps 300-3000rpm. > If switches aren't practical, you could probably use pyvcp to allow > the > operator to tell the system what gear they are in. Then an open loop > system will work. If they enter the wrong gear, you'll get the wrong > speed, but you won't have to tune PID, and it will be unconditionally > stable. The pyvcp sounds like a good idea, I wasn't sure how to set things from the screen. I don't guess this would be setable in the .ngc file, would it? I write operator instructions in the ngc files so if I need to make the part again in a few months from now I'll know how it was set up. Another idea I had is that when the S value changes, I could slowly increase or decrease the spindle speed until it was close, and then run open loop until the next S change. That way spindle syncronized moves won't cause a problem, like they would with a closed loop, when the spindle position is zero'd. Thanks again! Roger Neal ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
