Hi I also want to build 2nd gantry machine. my first gantry machine is where table moves and i doesn't need dual drive because design of machine. this type design is 2 times bigger in compare to design where table is fixed. i will build new gantry with fix table without of dual drive by installing gear rack http://www.rushgears.com/Gear_Types/gearRack.php/?referrer=GoogleGearRack&gclid=COm2wab0vZ8CFSAkagodxk7jzg on both side of machine and joint gears with simple shaft. only 1 servomotor need to drive that axis. Diameter of shaft can be from 1" - 1.5" Overall accuracy of machine can be same as any dual drive. using gear rack will make whole machine much simple and less expensive.
thanks aram > > Arnold, > > I have not solved it but I think I know the direction to go. After > digging though the mailing list archive I found one thread that addressed > homing of a dual servo gantry. It looks like it will take some work in > HAL - I have included an excerpt of the thread below that sums it up > fairly well. Other than this, the info I have found has been for steppers > or solutions that handled gantry squaring outside of EMC2 by mechanical > means or though the servo drives themselves. I would be surpised if > someone has not figured this out given the number of large format machines > running EMC2. I am 6 to 9 months away from having a gantry to test with > but I would be happy to work with you on this if someone doesn't chime in > with a solution. This is something that should become a native element of > homing in EMC2 as it is fundamental to the operation of a dual drive > gantry. > > > > Jeff > > > > Re: [Emc-users] syncing two motors to one axis > From: Jon Elson <el...@pi...> - 2009-04-01 17:28 > > Len Shelton wrote: >> So let's say you have two drives, two motors, and two home switches on >> the >> same axis (gantry type machine). The problem with this arrangement is >> synchronization. The control needs to be aware of the two motors and >> needs >> to home both at the same time. While homing, we need to bring both >> motors >> towards the home switches together then independently home each motor >> when >> it reaches the home switch. >> >> How can this be done in EMC2? >> > We've gone over this a dozen times, at least. It would take about 10-15 > lines of HAL and several HAL components to perform the logic. > Basically, you make the two motors run at the same rate. As each motor > hits the home switch, it stops. When both have touched home, they move > together again to complete the precision home sequence to the encoder > index pulse. EMC2 already has features in HAL to handle tandem axes > like this, once homing is done. You feed the lettered axis (as in "X") > position to two numbered "joints" as in zero and one. So, the only > detail up in the air is how to do the homing. > > Jon > > >> Message: 9 >> Date: Sun, 10 Jan 2010 11:32:40 +0100 >> From: Arnoldritercnc <arnoldriter...@gmail.com> >> Subject: Re: [Emc-users] Homing dual drive gantry >> To: "Enhanced Machine Controller (EMC)" >> <emc-users@lists.sourceforge.net> >> Message-ID: <4b49acc8.7050...@gmail.com> >> Content-Type: text/plain; charset=ISO-8859-1; format=flowed >> >> I have the same problem. Jeff, have you solved it? >> Any help will be very appreciated >> >> Thanks > > _________________________________________________________________ > Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. > http://clk.atdmt.com/GBL/go/196390709/direct/01/ > ------------------------------------------------------------------------------ > This SF.Net email is sponsored by the Verizon Developer Community > Take advantage of Verizon's best-in-class app development support > A streamlined, 14 day to market process makes app distribution fast and > easy > Join now and get one step closer to millions of Verizon customers > http://p.sf.net/sfu/verizon-dev2dev > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Throughout its 18-year history, RSA Conference consistently attracts the world's best and brightest in the field, creating opportunities for Conference attendees to learn about information security's most important issues through interactions with peers, luminaries and emerging and established companies. http://p.sf.net/sfu/rsaconf-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
