2013/6/9 John Kasunich <[email protected]> > 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. >
Well, it's a shame I did not checked that before, but now I see motion.spindle-brake only. 2013/6/10 Jon Elson <[email protected]> > 2013/6/9 Florian Rist wrote: > > >>> Other is powering brakes when commanded velocity magnitude > >>> exceeds some near-zero value. > >>> > You really don't want to do this on most machines. Possibly on a CNC > turret > punch you need to hold the work when the punch comes down, but otherwise, > locking the axis every time it stops moving causes a discontinuity in > the servo > drive. In some cases it could cause the drive to go into current limit > and fault > while locked, depending on drift and stiffness of the servo amp. When > the brake > is released, the drive would suddenly jump. That's a good point. I have not used it, but most servo drives have a setting for velocity limit to engage brake, and I wanted to replicate that. It's just the logic probably must include certain f-error limit, or PID outputs (as I pointed before) etc. Even so, having brakes repeatedly switching on and off is not good for machine tool, while for other applications it can be nesessary. Looks like using enable outputs is the best solution here. 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
