Re: [Emc-users] Pico Sytems UPC and a Hardinge CHNC
Kirk Wallace wrote: > Just in case, my guess is that the internal resistor was sized for > current limiting 5 Volts, so the current would go up by around 120% > without an external resistor, which is okay? > The 5 V isolated source is IN the UPC (and USC) board. It cannot be bypassed the way it is wired. You create a one by closing a circuit from the individual signal to the isolated ground. So, each digital input is a sourcing terminal that is grounded to complete the circuit. So, you never supply current to the input, you sink current from it to the ground terminal. (Harder to explain this in words that to draw a picture.) The internal resistor is 1 K Ohms, so you get about 3 mA from the 5 V source, through the opto-coupler's LED, the resistor and then to ground. If you were to apply 12 V to the input, that would reverse bias the opto-coupler's LED with about 7 V, which is definitely above the ratings. I know that adding a diode drop in the circuit will not prevent it from detecting the switch closure. Jon -- 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
Re: [Emc-users] Pico Sytems UPC and a Hardinge CHNC
On Tue, 2012-01-24 at 12:26 -0600, Jon Elson wrote: > Kirk Wallace wrote: > > > > 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. > > > Yes, that is what I'd recommend. I think only the diode is needed, the > resistor is already > provided in the UPC board. > > Jon Just in case, my guess is that the internal resistor was sized for current limiting 5 Volts, so the current would go up by around 120% without an external resistor, which is okay? -- 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
Re: [Emc-users] Pico Sytems UPC and a Hardinge CHNC
Kirk Wallace wrote: > > 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. > Yes, that is what I'd recommend. I think only the diode is needed, the resistor is already provided in the UPC board. Jon -- 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
Re: [Emc-users] Pico Sytems UPC and a Hardinge CHNC
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
[Emc-users] Pico Sytems UPC and a Hardinge CHNC
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. -- 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
