On Mon, 2012-01-23 at 20:55 -0500, Ed wrote: > Someone out there probably has worked this out. Hardinge uses home and > limit switches and the turret encoder that use a pullup to 12 Volts. The > UPC uses isolated 5 Volts for the input ports. > > The big question is how did you interface these? Current limited > opto-isolators come to mind, small signal relays may work if they are > fast enough. Any other ideas? Many thanks to any that can help. > > Ed.
I use opto-isolators: http://www.wallacecompany.com/cnc_lathe/HNC/00013-1a.jpg http://www.wallacecompany.com/cnc_lathe/HNC/ but I used the paradigm of a switch closure at the time I did the installation, after giving it more thought and referring to: http://pico-systems.com/images/univstep.png it looks as if the inputs already go to an opto-isolator on the UPC anyway. It may be that a resistor (and a general purpose diode for reverse voltage protection) in series would work just fine. Limiting the current to the opto LED is the primary issue. The UPC and turret encoder 12V supply grounds would need to be tied together in order to close the circuit. The logic sense may need attention too. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
