On 10/07/2013 05:45 AM, Ricardo Moscoloni wrote: >>> I don't like USB much for using with LinuxCNC. The VFD/Modbus components >>> work well enough or can be modified easily enough to get what I need. >>> Plus I don't know Ladder. >>> I have a few VFD's that I run three twisted pair to for FWD, REV, and >>> speed PWM. With a micro controller I could get that plus monitor >>> frequency, load, and other things with two pair. > > well thats interesting! the avr will connect to LCNC through serial port?
Yes. Either with RS-232, or more formally RS422/RS485. It is common to use an adapter on an RS-232 port to get RS-422. > i like to hear what is the usb disadvantage in this particular application. The first thing that comes to mind is that I have had major latency hits in the past by plugging in a USB device, so I have gotten used to avoiding USB when I can. USB was designed to interconnect consumer devices for short runs in home or office environments. Modbus/RS422 was designed for industrial environments. Many VFDs, PLCs and other machine devices have Modbus built-in or available as an option. I don't know of any off-hand with USB. > where i* can find some info about modifying those components (* > without much programming skills....) ... snip The Wiki link: http://wiki.linuxcnc.org/cgi-bin/wiki.pl?VFD_Modbus has an outline of the procedure for modifying an existing component at the bottom of the page. It is probably too sketchy for a beginner, but it really isn't that difficult to do. The sample file: http://wiki.linuxcnc.org/cgi-bin/wiki.pl?New_File_From_Vfs11 has a comment at each file location that needs to be edited for the particular device you have. The C programming should not change. You will need the device manual with a list of the functions and their corresponding register addresses, then create HAL pin names for each function. It would help to go through the comp section of the LinuxCNC manual and make a couple simple components before trying to run comp on your Modbus component. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60134791&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
