On Saturday 27 October 2018 21:46:59 Alan Condit wrote: > I have a homemade encoder on my lathe spindle. I am feeding the > encoder outputs into the encoder spindle inputs on the 7I76. The > reported rpm seems to be fluctuating wildly. I want to look at the > signals to see if the width of the signals is about the same for the > index on time and for channel A and B on and off times. Is it possible > to look at the encoder signals with hal scope? Or do I need to drag my > oscilloscope out to the shop. I don’t see the pins in the hal file. > > Am I even thinking about this correctly? > > Alan > You will have to drag it out Alan, the halscope is simply not fast enough. And look at the bobs output.
And home-made I've done, but you have to resort to hal tricks , or at least I have if the encoders resolution is greater than 2 degrees a passing edge. I was plumb amazed that with a 1000 line encoder on the tail end of the motor shaft, with scales in the 7000 to 14000 range, that I was able to run the P-Gain from 3 on up to the 20-40 area. Spindle speed control is so accurate that until the chirp of the current limit of the pwm-servo I'm driving that motor to around the 2 hp mark with, I have no clue that its working that hard. So I would highly recommend a higher resolution encoder. The encoder I bought on ebay for about a $20 bill turned out to have differential outputs that I had to use a couple rs485 boards $1 each these daysto make it a single ended signal, which meant I had to bypass the opto's on the bob to get a clean signal into a 5i25 card. Otherwise it was way too fast to get a usable signal into the 5i25. -- Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
