I think the main thing about estop is that A. When hitting E-Stop all movement stops ASAP. B. There is no chance things start moving again after the E-stop button is reset. Typically a separate "start" button must be pressed before things may start again.
I recommend that these circuits be implemented in hardware. see therac-25 for how things could go wrong. https://en.m.wikipedia.org/wiki/Therac-25 I have seen machines that leave drives powered during estop but they have an enable loop that is part of the "hardware" estop loop. (the more modern machines tend to follow this pattern.) I have seen machines that completely cut power to all drives as part of the estop loop. It is up to you to engineer the appropriate way of handling this. I make these decisions by imagining that if my arm were caught in a particular machine .... which way of doing it would result in less injury. Big machines with lots of momentum would probably cause less harm with controlled powered stopping... cutting power on those drives may result in more harm. In a home machine with sketchy Chinese drives... cutting all power might be ultimately safer.... it all depnds. My father lost a hand in the 70's because he reached into a machine that did not follow this e-stop protocol. It is serious business even for small machines. Please take it seriously especially if people other than yourself will be operating them. -Curt On Sun, Aug 1, 2021, 3:47 PM Feral Engineer <[email protected]> wrote: > With safety relays, they require an external reset after being released. > Every machine tool I've been on in the last 20 years operates in this > fashion. > > Release estop > Press "power on" or "drive enable" button to reset the pilz > > Phil T. > The Feral Engineer > > Check out my LinuxCNC tutorials, machine builds and other antics at > www.youtube.com/c/theferalengineer > > Help support my channel efforts and coffee addiction: > www.patreon.com/theferalengineer > > On Sun, Aug 1, 2021, 3:14 PM Nicklas SB Karlsson <[email protected]> wrote: > > > Anyone have any experience or knowledge with emergency stop circuit? > > > > > > Connected a special safety relay breaking the 24 volt power supply > > driving the relays today. Then emergency stop have been pushed it have > > to be reset before relay is switched on again. > > > > > > Nicklas Karlsson > > > > > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
