On Thu, 2009-06-11 at 20:14 +0200, Sven Wesley wrote: > While reading another post I realized that EMC can handle the encoder input > by itself - and at the same time I realized that I can run one of my > machines at home as a direct encoded closed loop. After some more reading > and digging at the cnclinux wiki I think it should be possible to do it with > a Mesa card, so I went to the Mesa webpage and somewhere between the first > and second click on that page I was lost... > I have a machine with linear encoders for a DRO. > I want a driver thingy that I can control with EMC. > I can get any servo between 36 and 90 V for a decent price. > I want to add another parallel port and run the encoders directly to EMC. > > Is this possible, what card do I need and how the heck do I configure EMC? > > > Regards, > Sven
The terminology can get in the way sometimes because 'encoder' can mean different things. For this post, encoder means a linear or rotary device that converts motion into electrical pulses in a quadrature form (A,B). Decoder means a device or software that converts quadrature pulses into counts in a register. The simplest encoder system can have an encoder with A and B signals connected to a pair of parallel port pins, then connected via hal to a software decoder, http://www.linuxcnc.org/docview/html//man/man9/encoder.9.html The software decoder outputs a count which may be connected to other components such as PID. For high resolution or fast motion, the software decoder may be too slow. If you need more speed, a hardware decoder on an FPGA card can be used. It does what the software decoder does, but in hardware and EMC2 just sees the hal connection as a count. I haven't tried it, but theoretically you could use a pair of general purpose digital inputs on the FPGA, then hal connect the A and B signals to a software decoder in EMC2. I have left a lot of the details out, but basically you need to figure out which decoder will work for you, then use hal to connect the signals. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ Crystal Reports - New Free Runtime and 30 Day Trial Check out the new simplified licensing option that enables unlimited royalty-free distribution of the report engine for externally facing server and web deployment. http://p.sf.net/sfu/businessobjects _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
