On Mon, 6 Feb 2012, Erik Friesen wrote: > Date: Mon, 6 Feb 2012 17:57:10 -0500 > From: Erik Friesen <e...@aercon.net> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Control board > > The mesa card looks interesting to me. The catch is, how is one going to > go about doing spi and pulling the data into emc2?
There is FPGA firmware support for SPI with up 16 channels and up to 32 bits of data/channel and clocklow/2 = 16.666 or ~25 MHz) There is also HostMot2 driver support for the SPI firmware (in LinuxCNC 2.5 or >) I assume everything > would have to be bit banged, and is not taken care of in the fpga. It also > says it has quadrature encoder interface, but once again, how is this > handled? If this was handled with a accessible register, that would work > pretty well. > Its fully supported by the HostMot2 driver. if you have a running LinuxCNC system type: man hostmot2 for Mesa HostMot2 driver/firmware capabilities on your system > On Mon, Feb 6, 2012 at 1:28 PM, Kirk Wallace > <kwall...@wallacecompany.com>wrote: > >> On Mon, 2012-02-06 at 12:29 -0500, Erik Friesen wrote: >>> I am not so sure about the parallel port and encoder idea though, the >>> encoders I see are up to 1000 per rev, that requires a pretty fast base >>> period to handle that, not? <2us ? >> >> In reference to my reply, I suggested that using the parallel port for >> encoders, but only if the encoder pulse rate is similar to the step >> rate. An FPGA PCI or parallel port board would be needed for decent >> encoder rates. >> >>> I also am not very clear on emc2 capability to manage analog inputs, it >>> seems easier to offload the deciding to an external mcu of some sort. >>> Also, how would emc2 handle encoders with steppers? >> >> In the normal stepper configuration file, the position command and the >> position feedback are software "shorted" together. >> >> core_stepper.hal >> ~~~~~~~~~~~~~~~~~~~~~~~ >> ... >> 25 # connect position feedback from step generators >> 26 # to motion module >> 27 net Xpos-fb stepgen.0.position-fb => axis.0.motor-pos-fb >> 28 net Ypos-fb stepgen.1.position-fb => axis.1.motor-pos-fb >> 29 net Zpos-fb stepgen.2.position-fb => axis.2.motor-pos-fb >> ... >> ~~~~~~~~~~~~~~~~~~~~~~~ >> >> This is because when a step is sent out, it is assumed that the step >> completes properly, and besides, a normal stepper system has no way of >> providing feedback. I haven't worked on a stepper system with encoders, >> but I think one replaces the above stepgen feedback with the encoder >> output. >> >> This link indicates there is are example files somewhere?: >> http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Steppers_With_Encoders >> >> For the cost, this may be a good analog trip indicator: >> http://www.sparkfun.com/products/9147 >> >> The biggest problem might be in conditioning the analog signal to a 0 - >> 5 Volt range. One could use the USB connection as is, or change the >> program to just send out a one bit or watchdog signal. Being a >> microprocessor, the trip conditions could be quite sophisticated. >> -- >> Kirk Wallace >> http://www.wallacecompany.com/machine_shop/ >> http://www.wallacecompany.com/E45/index.html >> California, USA >> >> >> >> ------------------------------------------------------------------------------ >> Try before you buy = See our experts in action! >> 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-dev2 >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > ------------------------------------------------------------------------------ > Try before you buy = See our experts in action! > 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-dev2 > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Try before you buy = See our experts in action! 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-dev2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
