On Wednesday 19 March 2014 05:32:41 Ed Simmons did opine: > Hi all, > > I've just set up closed loop control of the spindle for our machine - we > haven't yet built the new control box so I've just been experimenting > with the correct software set up for what is planned. > > I'm happy to have spindle speed control in the machine now and I've > confirmed the control works with a combination of Hal scope and a real > scope and signal generator. Motion is correctly delayed until the > spindle is at speed. What I expected to also happen at this stage was > that the machine would stop if the spindle speed dropped out of range or > stopped - but this doesn't happen. > > I ran the splash gcode in axis, provided the appropriate spindle speed > input signal from the signal generator after the motion paused to wait > for the spindle at speed signal, then motion began. Once it was > 'cutting' I stopped the spindle signal to see what would happen and it > continued cutting. > > Is there a way of making sure no harm comes to the work/tool in the case > of the spindle stopping or slowing down substantially? > > Thanks in advance, > > Best regards, > Ed > This is something I've sorta "doodled on a napkin" about. It would need one of two sensors to detect the slowdown, and an input line back from that sensor. For me, a hall effect ammeter would be the best deal as this controller is extremely stiff in speed control, so the best way I could do it would be to sense the amperage and throw an e-stop if, once in motion, the motor current exceeded something in the 1 ampere range. Scale that to your machine of course since mine is a toy.
For those whose speed controls aren't as stiff, but have encoders like needed for rigid tapping, a wcomp comparing commanded to actual from an encoder could do a similar function. Once the method of detection has been determined, the rest of it is an exercise in editing your .hal file to apply the logic. A full e-stop can be initiated, or the feedrate could be zeroed, leave the spindle on for a few milliseconds so it might cut itself free, and then stop it. Its all hal file editing to do what you want. But obviously you can't zero the feed rate AND raise Z to a safe height. Or at least I've not seen a way to do that. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. Written by three acclaimed leaders in the field, this first edition is now available. Download your free book today! http://p.sf.net/sfu/13534_NeoTech _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
