Peter W. John K. and the EMC crew at large. I am helping a friend convert a Shop Task to EMC control.
We have fitted the steppers & belts and anti-backlash kit parts from Shop Task, mounted roller switches at each end of the bed and carriage axis and an upper switch for the Mill quill. Gecko G251's are mounted on a heat sink rail. A Keling KL-5010 Linear power supply is fitted with a over voltage bleed circuit to dump power over 54V. Plan is to have a Mill and a Lathe machine profile depending on the job at hand. Due to the 1/10 step nature of gecko drives a Mesa 7i43 was selected to provide stable pulse streams up at the rates we want. The Screws are .1” lead and the belt drive is a 2:1 reduction so end result is 40,000 pulse per inch. Its taken 20 months to get this far and we have almost everything else needed in a box ready for final assembly/wiring. AND THAT IS Where my questions start. Looking at the low end BOB(s) most are just using the power supplied from the para port and running it through a switch or series of switches for HOME and LIMIT. I have heard that due to the low power involved such wiring is subject to noise and false trips. Thanks to the Mesa 7i43 spare I/O is not a problem – but I am not sure as to how to best use this I/O for the switches and to drive 3 SSR ( Stepper power on, Lathe spindle, Mill spindle.) The roller switches have both N.O. & N.C. contacts. Back in the days when Radio Shack still stocked tubes, I worked for awhile in electronics assembly, I don't have a background in the theory, but I can follow the schematic well enough to get by. So now its time to tear off a big sheet of butcher paper and rough out a wiring diagram. ( The “Big Picture”, I'm in trouble now! ) I now think I'm going to need a 7i37 for the limits and to drive the SSR's. My E-stop chain runs power through a DPDT switch then to an SSR so EMC must enable the power and can cut power – but I don't know how to feed back to EMC if the E-stop manual switch is still active ( power to supply off – and power from Capacitor shorted through dump resistors). Likewise does the output to the gecko's need to be isolated? I have a few “National Instruments” 50 IDC to screw terminal break outs but I have not had time yet to hunt down what I/O lines HM2 uses for its stepgen output. ( care to point out the proper link for this info?) We just installed the limits and we feel so close... I will have to leave for work again in a few weeks and I'd like to get this running so that the issues will be learning EMC flavored G-code while cutting air test parts while I'm gone. I have put both of my own machine conversions on hold since I promised to make this conversion happen. I have poured my own money into this project and now I'm ready to get what it takes to complete the job – I just need help making the right choices because I want to get it right the first time. I just fixed my net box so I can get on IRC and with a little hand holding and spoon feeding maybe hammer this out. Thanks all. I mentioned John K. because he's been down the Shop task conversion road, so any pointers or ideas or pot holes to avoid are greatly welcomed. Greg Bentzinger ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
