On 13 November 2010 02:00, Peter Cauchy <[email protected]> wrote: > If the parallel port is not putting out BTW 4 and 5v, I do not > understand how to increase this.
It possibly helps to stop thinking in terms of voltage and consider current. The driver has opto-isolated inputs. When a current flows through the LED in the opto-isolator either OPTO->DIR or OPTO->STEP then the intenal LED lights, and turns on the output photo-transistor (which might well be working on a completely different voltage, and be referenced to a completely different earth/ground level) If you set the p-port pin to 0V, then current flows through the opto and turns on the internal logic. When you set the p-port pin to +5V then current can no longer flow into it (and its voltage should rise to 5V). Parallel ports are typically open collector with a pull-up. http://en.wikipedia.org/wiki/Open_collector If, wired as described here, the voltage measured on the p-port pin does not rise to the OPTO voltage then it might be that one of the opt-isolators is not working properly. If you connect an ammeter between the p-port pin and the DIR terminal you should see 0 mA with the pin high, and probably 10mA or so with the pin low. For messing about with this, the P-Port tester here is probably helpful: http://wiki.linuxcnc.org/emcinfo.pl?Parallel_Port_Tester -- atp ------------------------------------------------------------------------------ Centralized Desktop Delivery: Dell and VMware Reference Architecture Simplifying enterprise desktop deployment and management using Dell EqualLogic storage and VMware View: A highly scalable, end-to-end client virtualization framework. Read more! http://p.sf.net/sfu/dell-eql-dev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
