So the e-stop should be mounted to the physical machine and not be a button on your cell phone. Makes sense.
But an interesting question is this: Let's say you have a foolproof e_stop mounted to the machine and then one day you build a remote monitoring web page that can live stream video form a mill that is far away. Should yu put an e-stop button on the web page, knowing full well that 100 computers need to work to get the e-stop message from phone to cell towers to server to the mill. Is it "wrong" on have this unreliable button? One argument is that it can fail if the server is down the other is that at least you have a good change to shut down the remote machine. Obviously the e-stop on the physical machine can use a relay or even a NASA-style cable guillotine. But it is unclear abot remote e-stop. One argument is that if you are near the machine you could be injured if the e-stop fails to stop the machine but if you are 5 miles away looking at a video the e-stop is only there to save a part from a g-code error so it need not be as robust. Notice tht LinuxCNC's "axis" app has a red-estop button you can click. It works only as long as the software works On Fri, Jun 5, 2020 at 12:38 PM John Dammeyer <[email protected]> wrote: > On any kind of pendant that has an ESTOP the button must physically > interrupt the circuit. So if you are using USB, for example the cable > needs to have two extra conductors for the NC ESTOP circuit. > > Doesn't matter if the Pendant is a full featured CNC controller or just a > simple unit with an MPG and a few buttons. > > John > > > -----Original Message----- > > From: N [mailto:[email protected]] > > Sent: June-05-20 12:30 PM > > To: Enhanced Machine Controller (EMC) > > Subject: Re: [Emc-users] How to get data to HAL from USB, serial or > socket? Emergency stop > > > > > ... > > > I think e-stop is a desired feature but it will never be as reliable > as one > > > that is wired to the machine that does not depend on computer software. > > > > Agree. Something simple to check, have seen there are safety classed > relays but are not sure about the standards. > > > > Safety Integrity Lev SIL and functional safety come to my mind. It is > simple to implement an emergency stop in software and/or > > hardware but bugs happens and is rather likely to have severe > consequences as it quite often is a reason to push emergency > > button. There are safety standards that must be fulfilled. > > > > > > 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 > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
