I have managed to read the initial serial data which defines the absolute position of an axis. The A and B channels of the absolute encoder are taken to the 7i33 on P2 of a MESA 5i23 as usual, The A channel which also carries the serial data when enabled initially, is also taken to a GPIO input on P4 of a Mesa 5i23, which also has a 7i37 on P3 for other purposes.
A component running at a thread rate matching the baud rate of 9600 of the serial data catches the serial data and interprets it to give the number of full revs Nf of the encoder from its set ref point. After the eight bytes of serial data is received, the encoder also sends out a number of A/B pulses providing the increment count C for a fraction of a rev. This count is given by the 5i23 encoder count. The total number of revs from ref point is then Nt = Nf + C/400, for 400 counts per rev. With Nt and the joint scale of degrees/encoder-turn I have the joint position as degrees from its absolute ref point. I now have to use the value to set the absolute position for the joint, but have not found the best way to do this in Linuxcnc yet. Any ideas from the experienced Linuxcnc users on this? Rudy ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60133471&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
