On Sun, 8 Apr 2012, Jeshua Lacock wrote: > Date: Sun, 8 Apr 2012 15:14:15 -0600 > From: Jeshua Lacock <jes...@3dtopo.com> > 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] Mesa counter card? > >
>Can anyone tell me how I would wire up the encoders? Are they connected >through the parallel cable, or some other way? > >If anyone from Mesa is listening, can you provide a crude diagram? I am a >visual learner, so that would be most appreciated. TTl (single ended) Encoders can be connected to the bare FPGA pins. Normally encoders have 3 pins each: A,B and I (or Z) so if for example a 5I25 FPGA configuration had encoder 0 connected to parallel port pins 1,2, and 3 you might wire encoder0-A to parallel port pin 1, encoder0-B to parallel port pin 2 and encoder0-Z to parallel port pin 3. (if you dont have or need the index/Z pin it can be dropped) There is a risk with direct connection of these signals that the FPGA card could be damaged if either ESD or excessive voltages were applied accidentally to the I/O pins (This also applies to standard parallel ports). The 5I25 is safe for inputs from -.6V to +7V. If a voltage beyond this range is applied to the FPGA pins, the 5I25 will likely be damaged. For this reason we supply breakout boards that are more rugged. Also for high speed and noise immunity, differential encoder signals are preferred to single ended signals. These differential signals are also supported by our breakout cards. All that said, for simple step/dir + TTl encoder use, you can get away without any breakout card. For example the G540 configuration is pinned out to connect directly to a G540 multi axis step drive. This in no way means it would only work with a G540, just that its pinout matches the G540 so no special cable/adapters are needed to connect the 5I25s DB25 connector to the G540s DB25 connector. If you wanted to use the step/dir outputs of a G540 configuration on individual step drives you would just need to check the G540 FPGA pinout and wire the "parallel port pins" accordingly. That is, there is nothing G540 specific about the configuration except its pinout. If you have an existing parallel port pinout with encoders and step/dir, this can easliy be duplicated in a custom 5I25 configuration. This probably sounds more exotic than it really is, as only a single pinout definition file needs to change to generate a new configuration, basically a 5 minute cut/paste edit job and a re-compile. >Best, >Jeshua Lacock >Founder/Engineer >3DTOPO Incorporated ><http://3DTOPO.com> >Phone: 208.462.4171 Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
