I think there are two levels of "Stop". One can be implemented in software and might be a function key (rather unreliable) or simple mechanical button that is monitored by hal. These solutions work if the software works. But if there is a serious bug in EMC or your configuration this solution fails
The most reliable thing is to buy one of those big 2" diameter estop buttons that have a mechanical latch that you trist to release. This is a big button that you hit with a fist to activate. The best setup is if the e-stop button supplies power to keep relay contacts closed. SO if the power is cut (by slamming your fist on the button) then power is cut to the motors. Be sure to handle back EMI with diodes across the reply. You need to use the "normal closed" contacts in the switch so that if some connector comes to lose the machine stops. Failures in connections should always half the machine. Do NOT use a latching relay. You want the machine to stop when the power to the relay stops The question is what kind of problem you are addressing? Are you trying to solve the problem of when a g-code file has a bad number in it? Or when there is a serious software bug or a serious hardware failure. If the later then the e-stop system has to be 100% independent of the computer controller. Of course, you can always simply connect everything, the computer, and the motors to the same AC power switch. If there is a problem with back EMF, address that. On Sun, Jul 21, 2019 at 4:11 AM andrew beck <andrewbeck0...@gmail.com> wrote: > Hi guys > > I have got my cnc mill control panel working ok now just have some > questions about the best and proper way to implement the safety E stop > circuit and initial power on of the cnc machine > > I did some searching of course, but thought I would ask here and see what > the latest and best way is. searching on the forum, some of the info was a > little dated. so if anyone has any advice I would most appreciate it. I > saw on Youtube what samco(skunkworks) (I think his name is chris Radek) > has done. And this is pretty much what I want i think. > > I think this should happen when the E stop is pushed. > > Cut control power to all servos and main spindle VFD. > (I think I may need to just send a E stop signal to the VFD as it doesn't > have control power that I can cut.) It seems a big extreme to cut main > power and possible damage the vfd with loose high voltages etc. > > It should tell linuxcnc that the E stop is pushed. > I need to set up a latching relay somehow to make sure the E stop doesn't > turn back on until I turn it on within linuxcnc. > > Servo Power on setup. > > I want a Button I can push which enables all the servo drives( there is a > Servo on pin on the servo drives) and then also enable the vfd however I > need to do that. This is separate to the E stop. Currently I am only > using step and direction control and I am wondering how hard it will be to > tie in the encoder signals to linux cnc with another mesa card. otherwise > when i push the E stop I will have to re home the machine. anyway please > sing out with any feedback you have and ideas. I would love to get some > ideas here from those who have done this all before. > > I am using a mesa 5i25 7i76 combo. > > And I have all sorts of contactors etc. > > Regards > > Andrew > > < > https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail > > > Virus-free. > www.avast.com > < > https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail > > > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
