On Sunday 21 July 2019 07:08:52 andrew beck 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 am probably a poor one to advise since I have not a separate E-Stop on any of my machines, depending on the f1 and f2 keys to do it all, which also still leaves me subject who owns the keyboard focus. > (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. I use the F1 key to enable power and this includes the vfd by way of the usual 40 amp 400 volt SSR's which are easily controlled. The F2 key enables motion. In this way you have an onscreen tally as the the machines state. > 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) This can be done in the .hal file by enableing the servo drives from the status of the F1 key latch. > and then also enable the vfd Same here, fire the SSR's from the same signal. > > 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. I have not tried to do that, you will have lost your home if the power is cut. I use steppers and with the drivers still enabled by F1, the stop distance is rarely more than 1 count at working speed. But can if in a rapid move at the time of the stop take several steps which the feeback encoder will miss, so you should rehome. Servo's are another story, and should return to the null point when re-enabled. Here, I consider the F2 key as an E-stop as it stops motion as fast as it can, while leaving power on everything. Leaving power on the servo's, it seems to me would give a faster stop than killing power with its slow decay to zero. I don't think it would be too hard to rig a big red button to be the equ of pressing the F2 key. I made progress on getting more spare inputs, and am considering something like a doorbell button I can slap. But I can't find such a button without a light bulb across the contacts. You would have to cut the light bulb out and remove it, otherwise the switch is closed forever to a bob input pin. One could supply that pin with enough pullup power to light the bulb, but most doorbell are 24 volt circuits, so an si diode would be needed to protect the bob's input. So I'm not "kosher" but unless lcnc doesn't have keyboard focus, it works for me, and the diffs are minimal. I'd have a bigger problem figuring out where to put the switch so its in a consistent location so muscle memory could be depended on once you got used to it. Believe me, there is nothing more frustrating that recognizing the sound of a 15 hp water pump thats suddenly single phased, and your hand is headed to the off button, but is still 18" from it when the lights go out because the 1200 amp/phase building breaker has tripped like a 12 gauge, followed a few milliseconds later by the realization this fix is going to need around $125,000 and at least two unscheduled quorums on the state legislature called. One to authorize the purchase, and when its been built and ready to ship, write the check. Yeah, broadcast power klystrons are that expensive. Thats why we don't use them anymore. > 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. Good combo, I'm using it twice myself. > 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 Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
