On Wed, 2011-09-14 at 20:54 -0700, Ben Jackson wrote: > I have pin 1 of my parallel port connected to a relay that isn't driving > anything yet. When I start EMC2 I hear it click on/off. If I control it > explicitly with M64/65 (or other logic) it works fine, but even if I > do "setp parport.0.pin-01-out 0" it clicks at startup. I'm sure that's > the pin because if I "setp ... 1" it only clicks once and stays on. > > This might be happening with other outputs as well -- I always noticed a > stepper clonk at startup which might be the drivers enabling briefly. >
This should be normal. As Linux boots up and loads, it looks for and tries to set up any parallel ports, then initializes them for use with common peripherals. Pin 1 is commonly a data strobe pin and also uses inverted logic, so is "inactive" at 5 Volts. When data needs to be strobed the pin goes to 0 Volts. For EMC2, pin 1 is just another digital output so the standard Linux behavior doesn't match well. Other pins could change during boot up too. For this reason, it is preferred to use EMC2's charge pump feature to control enables for the parallel port buffers, break-out-boards, isolator boards, power supply or mains relays, ecetera. This way no parallel port output is passed to the machine until EMC2's machine ON feature is active. For more, see: http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?About_Charge_Pumps -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ Doing More with Less: The Next Generation Virtual Desktop What are the key obstacles that have prevented many mid-market businesses from deploying virtual desktops? How do next-generation virtual desktops provide companies an easier-to-deploy, easier-to-manage and more affordable virtual desktop model.http://www.accelacomm.com/jaw/sfnl/114/51426474/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
