Hi. I suggest to you to try the *mb2hal* component to do this job . I've tested it on TCP/IP and it works just fine. It is not so well documented as it should be (I mean some clear examples should give an opportunity of a wide usage of this well packed component. *THANKS to Viktor Rocco the Author of the mb2hal component*). You can do all the modbus stuff using mb2hal so all the pins from read and write functions are automatically generated . And you're not limitated to a max number of read or write instances as the modbus integrated into ClassicLadder have. So with mb2hal the "dirty job" is done trasparently for the integrator . As you should know the performances over serial/rs485 line depends also from the response time of the slaves and from how many instances you fragment your communication data/registers . One thing that I suggest to you is to buy a galvanically insulated converter, to use a proper connnection shielded cable and a speed of 19200 baud , take care about connections and in case use the termination resistors (in case of long wiring) at both line ends.
Alex On Fri, Dec 19, 2014 at 10:19 AM, 77dab <77...@tiscali.it> wrote: > > Yes, I know, I already made a Java software to control independently 8 > of those VFD via modbus, and it works. They can run up to 38600baud. > what timing do you think i can expect from a sistem like that in > LinuxCNC? something like 10 VFD messages per second? or better? > > On 18/12/2014 14:57, Todd Zuercher wrote: > > I am controling 8 VFDs on a single machine with Linuxchc through one > USB-RS485 converter (from Automation direct). No real problems for me > except some random com errors. It works good enough though. I have not > had to restart or anything like that because of them. They do fill up an > error log pretty fast when running from terminal. It can be a little slow > to respond sometimes, reading and writing to 32 different registers at > 9600bps plus rewrites for bad com. > > > > It can be a little tricky to set up, you have to know all the modbus > details about your drives (every manufacturers drives are different), and > configure mb2hal to use them (there is nothing automagic here). > > > > ----- Original Message ----- > > From: "77dab" <77...@tiscali.it> > > To: Emc-users@lists.sourceforge.net > > Sent: Thursday, December 18, 2014 6:53:40 AM > > Subject: [Emc-users] Modbus > > > > Hi all, > > I have on my hand some mitsubishi VFD with 550w winches. > > I would like to try to move them using LinuxCNC. > > the thing is not meant to be Real time, and I've read the modbus module > > lives in User space and it's not RT. > > So, my question: > > Since it isn't RT, can I drive the rs485 thru a USB->rs485 converter, > > using a laptop? > > > > Thanks, Davide. > > > > > ------------------------------------------------------------------------------ > > Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server > > from Actuate! Instantly Supercharge Your Business Reports and Dashboards > > with Interactivity, Sharing, Native Excel Exports, App Integration & more > > Get technology previously reserved for billion-dollar corporations, FREE > > > http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > ------------------------------------------------------------------------------ > > Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server > > from Actuate! Instantly Supercharge Your Business Reports and Dashboards > > with Interactivity, Sharing, Native Excel Exports, App Integration & more > > Get technology previously reserved for billion-dollar corporations, FREE > > > http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > ------------------------------------------------------------------------------ > Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server > from Actuate! Instantly Supercharge Your Business Reports and Dashboards > with Interactivity, Sharing, Native Excel Exports, App Integration & more > Get technology previously reserved for billion-dollar corporations, FREE > > http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
