On Wed, 23 May 2012, Jon Elson wrote: > Date: Wed, 23 May 2012 21:31:26 -0500 > From: Jon Elson <el...@pico-systems.com> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Encoder Redundancy? > > Peter C. Wallace wrote: >> Which is a good illustration of the limitations of step/dir servos since >> LinuxCNC can't "see" whats happening in the drive, which rules out a lot of >> hardware fault mitigation strategies. >> > Well, really, detecting all possible cases of a failed encoder is not > that easy. > In this case, using my Gecko Interface board, LinuxCNC CAN see the encoder, > and would have E-stopped the system, IF it had seen uncommanded movement. > But, with the encoder not powered or otherwise not working, it gets no > indication of the runaway. > > Jon
That was my point: step/dir servos do not provide a easy way to detect a runaway. If LinuxCNC is running the loop, a saturated PID output is an easy way for systems with "normal" servos to detect runaway. This works fine with unpowered or open wire encoder situations. > > ------------------------------------------------------------------------------ > 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 > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
