Hi Raymond, I used Automation Direct servo drives on that job and they can be setup to shutdown on excessive following error. (Deviation from the step and direction commanded position). They can also be shutdown by an external input. So if you cross wire the drives so if one shuts down on following error, it shuts down the other drive and visa versa, it becomes a self protecting system. If either drive has excessive following error it kills itself and also the other drive. That prevents the gantry from being racked out of position if something goes wrong.
A common reset wired to both drives can also bring them back to life after a shutdown. It works well and is quite simple once it is implemented. Dave On 1/9/2015 4:03 PM, rayj wrote: > Greetings Dave, > > I have some long term plans to build a gantry similar to the one you > describe. > > When you say it kicks out the controls, I'm not sure what you mean. Is > there some physical safeguard, like a detent or or clutch, or is it > something in the software you're talking about. > > TIA > > Raymond Julian > Kettle River, MN > > The things we admire in men, kindness and generosity, openness, honesty, > understanding and feeling are the concomitants of failure in our system. > And those traits we detest, sharpness, greed, acquisitiveness, meanness, > egotism and self-interest are the traits of success. And while men > admire the quality of the first they love the produce of the second. > -John Steinbeck, novelist, Nobel laureate (1902-1968) > > On 01/09/2015 10:47 AM, Dave Cole wrote: >> I did one of these several years ago. The machine has 1 KW servos on >> each end of the gantry driving ball screws. The gantry was quite >> rigid so when the power was removed it self squared. There was one one >> home switch. I ended up using servo drives in step and direction >> mode and fed them with a pulse train from LinuxCNC. That worked out >> fine. I fed the same step and direction signal to each gantry drive. >> If there is any significant following error on either drive, it kicks >> out the controls so the gantry cannot become racked out of shape. >> It has been running like that now for over 3 years with no issues and >> the machine runs up to about 700 ipm. The machine runs every day, >> sometimes two shifts per day. >> I considered doing two separate closed loop axes back to the PC, but I >> thought it would be easier to try the step and direction approach >> first. That worked, so I stuck with it. >> No regrets on that decision. >> >> Dave >> >> On 1/9/2015 10:57 AM, Eric H. Johnson wrote: >>> Hi all, >>> >>> >>> >>> I am looking to do an upgrade on a large XY table where the gantry is driven >>> by to oppositely mounted servo motors. Both sets of encoders run back to the >>> existing controller. Can I just give a generous deadband to the slave axis, >>> or is there a better way to address this configuration so the motors don't >>> fight each other. I believe it uses a single home switch which can then be >>> fed to both axes for purposes of homing. Anyone done this? Anything else to >>> look out for? >>> >>> >>> >>> Thanks, >>> >>> Eric >>> >>> >>> >>> >>> <http://t.senaltres.com/e1t/o/5/f18dQhb0S7ks8dDMPbW2n0x6l2B9gXrN7sKj6v4LCQRN >>> 7fcnk8RJ6s6N8rBF7Rd3_yKW18Chwm1k1H6H0?si=6453247850577920&pi=8828d77849c9460 >>> b95fcaf96870fbe9d> >>> ------------------------------------------------------------------------------ >>> Dive into the World of Parallel Programming! The Go Parallel Website, >>> sponsored by Intel and developed in partnership with Slashdot Media, is your >>> hub for all things parallel software development, from weekly thought >>> leadership blogs to news, videos, case studies, tutorials and more. Take a >>> look and join the conversation now. http://goparallel.sourceforge.net >>> _______________________________________________ >>> Emc-users mailing list >>> [email protected] >>> https://lists.sourceforge.net/lists/listinfo/emc-users >> --- >> This email has been checked for viruses by Avast antivirus software. >> http://www.avast.com >> >> >> ------------------------------------------------------------------------------ >> Dive into the World of Parallel Programming! The Go Parallel Website, >> sponsored by Intel and developed in partnership with Slashdot Media, is your >> hub for all things parallel software development, from weekly thought >> leadership blogs to news, videos, case studies, tutorials and more. Take a >> look and join the conversation now. http://goparallel.sourceforge.net >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > ------------------------------------------------------------------------------ > Dive into the World of Parallel Programming! The Go Parallel Website, > sponsored by Intel and developed in partnership with Slashdot Media, is your > hub for all things parallel software development, from weekly thought > leadership blogs to news, videos, case studies, tutorials and more. Take a > look and join the conversation now. http://goparallel.sourceforge.net > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com ------------------------------------------------------------------------------ Dive into the World of Parallel Programming! The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
