Jon, After going through some doc about emc, I understood the encoder should work with one signal (A and Z). I'll give that a try.
I did some tests with the ir leds and fototransistors of a canibalized mouse and I guess this will work. I'll add an 7414 schmitt trigger to avoid noise. What I couldn't find in the doc was which polarity the signal must have. Although not important for A or B, maybe for the index pulse it is of importance. Also, do you know if there are special constraints about the Z pulse? Must it be high (or low) before the A becomes high or doesn't this play any role? Thanks for the info. Below a link to the technical drawing for mounting this on a sherline spindle: http://users.skynet.be/gedp/FILES/encoder.JPG http://users.skynet.be/gedp/FILES/encrend01.png Thx for the info, Geert Jon Elson wrote: > Geert De Pecker wrote: >> Is the problem with software encoding related to the speed of the pulses >> coming in? If so, would a low res encoder (homemade) of eg 20 ppr be a >> solution? >> > Yes, but you don't want it to be too coarse. There is some > filtering in the motion of the slaved axis, but if the encoder > was too coarse, there could be some stair-step like movement in > the Z axis. 20 slots in a home-made encoder would give 80 > quadrature counts, or 4.5 degrees per count. I would expect > that to work fairly well. Without quadrature, it would be 18 > degrees per count. I'd have real doubts about the accuracy or > "linearity" of a thread with an encoder that coarse. I am using > one with 6912 counts/rev, I know that is overkill, but it is > what I had. >> Does it have to be a quadrature encoder (see in the HAL doc that both A >> and B are used) or is there a solution with 2 signals: one index Z and >> eg only 'A'? I would assume that when 'B' is not used and >> encoder.N.x4-mode is false, it would also work? >> > The current code and hardware available all expect a quadrature > encoder. You could set up a variation on the code to allow a > different encoder scheme with only 2 channels, for instance. > Without changing the code, I don't think you could get it to > count with just one channel, even with the N.x4 mode false. > That just divides the counts by 4. > Jon > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
