I am busy converting a Motorman 6-axis robot to Linuxcnc. The original Yaskawa motors and servo drives are used. The motors are all fitted with absolute encoders. The encoders have differential A and B pulse trains, but the A channel is used in the beginning to send 8 bytes of serial data plus some incremental pulses to establish the absolute positions of the axes when activating the robot after a start-up. The 8 bytes give "P(+ or -)XXXXX(CR)" with M=XXXXX the number of full turns of the motor from the home position. The next incremental pulses (Po) give the number of counts of a partial turn. So if R is the number of counts/rev, the position in counts is M*R + Po. After this short burst of serial data and pulses the encoder behaves like a normal incremental encoder.
I have set up one motor on a bench and have tuned the PID for it. I have to reset the encoder count to zero before I carry on after the initialization, ie. I currently ignore the initial serial data and pulses, but of course like to use this data to have absolute encoding functional. A component seems necessary to read the serial data and count the initial pulses to set the initial offset. Has anybody perhaps prepared such a component. I have looked at the lsrio16.comp and could probably make something similar work for me. The tricky part for me would be to get the right clock speed to synchronize with the serial data speed of 9600 baud. I am using a Mesa 6i26 + 7i77 interface system. Rudy ------------------------------------------------------------------------------ Learn the latest--Visual Studio 2012, SharePoint 2013, SQL 2012, more! Discover the easy way to master current and previous Microsoft technologies and advance your career. Get an incredible 1,500+ hours of step-by-step tutorial videos with LearnDevNow. Subscribe today and save! http://pubads.g.doubleclick.net/gampad/clk?id=58041391&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
