On Wed, 23 May 2012, Jeshua Lacock wrote: > Date: Wed, 23 May 2012 00:08:12 -0600 > From: Jeshua Lacock <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Subject: [Emc-users] Encoder Redundancy? > > > Greetings, > > I turned on the power to my system today and my 180 pound gantry shot full > speed crashing hard into the end of my table. > > It hit with so much force it actually lifted the front two legs of the 500+ > pound table 6+ inches off the floor! Yikes! > > Luckily the machine only suffered minor damage, but needless to say I really > would like to avoid this from ever happening again. > > I was a stumped at first as the last time I used it everything was stable. > It turns out that I had a loose connection to the encoder. I am going to > soldier the wires on the pins of the encoder to prevent that from happening > again, but I was wondering if there is anything I can do to disable motor > power in the event a connection to a encoder is lost. > > I understand why it happened - without the encoder live the motor was just > attempting to position itself at 0. > > I am guessing there is not an easy way to detect this condition, but I > wanted to see if anyone else has any thoughts on the subject.
I think the saturated PID output is a fairly good way to detect this condition and certainly would have workied in this circumstance. The saturated PID detection does depend on some amount of I term to detect encoder failure type faults when the commanded position is static so a constant small error will eventually saturate the PID output. Errors when moving are easier to detect and handled by the built-in following error limits. > > > Thanks, > > Jeshua Lacock > Founder/Engineer > 3DTOPO Incorporated > <http://3DTOPO.com> > Phone: 208.462.4171 > > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
