Our Y axis has a brake. (vertical) we just have it hooked to the axis enable pins. When the drives are enabled - the brake is disabled... Seems to work great!
sam On 06/09/2013 03:44 PM, John Kasunich wrote: > At one time in the darks mists of history, EMC(1?) had an > axis brake output for exactly this function - it would turn > the brake on and off based on g-code commands. I'm not > sure if it made it into EMC2 and thus LinuxCNC. If I wasn't > lazy I would check the manual and see if the "motion" > component has a brake pin. > > On Sun, Jun 9, 2013, at 01:34 PM, Andrew wrote: >> 2013/6/9 Florian Rist >> <[email protected]<https://mail.google.com/mail/u/0/?view=cm&fs=1&tf=1&[email protected]> >>> Hi Andrew >>> >>> Hi Florian, >> >>> > It depends on when you need the brakes on. >>> >>> Well, the brakes are supposed to prevent the servo from moving when >>> powered off, for safety reasons but also to be able to power up the >>> machine without the need to home the axis (nor sure if this is really >>> possible) >>>> The simple solution is connect brakes to enable. >>> So I take the enable signal for the servo controller (7i39) and use that >>> to switch on the brae supply, right? >>> >>> I guess so. I usually use relay modules like this >> http://www.ebay.com/itm/251267628031 for that purpose. >> >>>> Other is powering brakes when commanded velocity magnitude >>>> exceeds some near-zero value. >>> sounds more elegant, but that means I have to use an extra i/o pin (no >>> problem there are plenty of them free) and generate the signal for it >>> (don't know how to do so, right now) >>> >> Yes. I would use abs to get absolute value of velocity and then comp to >> compare it to say 0.1 or 0.01 (slow enough but not zero). >> http://www.linuxcnc.org/docs/html/man/man9/abs.9.html >> http://www.linuxcnc.org/docs/html/man/man9/comp.9.html >> The question is which signal to use for velocity input: >> axis.N.joint-vel-cmd (or probably PID outputs) for each axis with 3 >> independent brakes, or motion.current-vel for common brake signal. >> Something like this. We can continue with details if nesessary. >> >> Andrew >> ------------------------------------------------------------------------------ >> How ServiceNow helps IT people transform IT departments: >> 1. A cloud service to automate IT design, transition and operations >> 2. Dashboards that offer high-level views of enterprise services >> 3. A single system of record for all IT processes >> http://p.sf.net/sfu/servicenow-d2d-j >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ How ServiceNow helps IT people transform IT departments: 1. A cloud service to automate IT design, transition and operations 2. Dashboards that offer high-level views of enterprise services 3. A single system of record for all IT processes http://p.sf.net/sfu/servicenow-d2d-j _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
