Hi Andrew, I'm top posting because I'm not really responding to anything specific that you've said. Only on how I've done it.
First the machine, one similar to a Grizzly G3616, has a locking RED ESTOP button, a SPINDLE ON button, SPINDLE FWD/REV and a COOLANT PUMP ON switch. There's also a 110VAC circuit for power feed and I tapped onto that for the DRO. It's all relay logic inside the control panel and wired in such a way that if the ESTOP is hit while the SPINLDE and/or COOLANT PUMP are ON then power is removed from both and the 4PDT relay running power to them, controlled by the ESTOP NC contact, is now released. One of the four poles of that relay was wired so that if the ESTOP is released nothing starts up again. All DPDT controlled systems that were in the relay enable circuit have to be switched off again before the ESTOP circuit allows power to this master relay. The 110VAC circuit to the DRO and power feed are also controlled by the 4PDT relay. So the scenario is, you hit ESTOP, machine stops! You untwist and unlatch the ESTOP and nothing happens even though you forgot to turn the SPINDLE switch off. Once you switch the SPINDLE switch back to centre OFF, power comes back on. So I added a relay and luckily the ESTOP switch had a second unused NC contact. Two pairs of wires come out of the control box to the CNC system. One of them is the ESTOP NC circuit. They have to be connected so they can be wired through a second ESTOP button and also a relay controlled by the PC. Now, hit either the ESTOP, or have the PC open a relay controlled by the CNC software ESTOP circuit and again it's like you've pressed the ESTOP button on the machine. Everything stops. The second output pair of wires are to the contacts of the extra relay I installed. At the moment they control the 220VAC Current Limit power relay to the CNC motor transformers. So a limit switch or some other CNC based ESTOP condition removes AC power to the Servo and Stepper Motor power supplies. The AC to the PC and the Breakout Board are not shut off nor is the 24V instrument bus. Here's the only down side so far. The filter capacitors on the big 105VDC Servo supply do have a crowbar over voltage circuit to prevent the back EMF from a decelerating motor exceeding a high voltage set point. (about 115VDC) This protects the Servo Drives. This same crowbar circuit is automatically switched ON when AC power is removed so a few seconds after AC is gone the DC has been bled off the caps. No remnant of high voltage remains for safety. But that does take a few seconds. The HP_UHU servo drives and the STMBL on the Rotary A axis all have their ENABLE controlled by the ESTOP circuit so motion control stops. Bu t it does take a few seconds for the DC power to vanish. However, the stepping pulses to the motors has been stopped by the ESTOP condition. The motors continue to turn but without stepping pulses input and so even if the driver isn't put into a disable condition, the encoder pulses returned to the driver no longer match and a following error occurs and the driver goes into a following error condition. I have my limit switches set a little bit away from the hard mechanical stops so as the motor coasts to a stop the leadscrew so the table runs into the mechanical stop but not really hard. Once power is back and the limit switch is overridden the system has enough power to move off the switch. But the higher the speed the further it coasts. Haven't figured out how to deal with that yet without giving up more motion at the far end. I've included the latest drawing. The only difference between the drawing and the machine is that the PC, Monitor and PMDX-126 BoB are all running off a second 220VAC current limit relay controlled by the Mill Master switch at the back of the machine John Dammeyer > -----Original Message----- > From: andrew beck [mailto:andrewbeck0...@gmail.com] > Sent: July-21-19 4:09 AM > To: Enhanced Machine Controller (EMC) > Subject: [Emc-users] looking for help on the best way to implement a > Latching E stop circuit > > 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
G3616_CNC_Wiring.pdf
Description: Adobe PDF document
_______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
