I have finally got to the point on my lathe where I can start tuning. The setup is: Mesa 5i20 driving a 7i29 with 1024CPR encoders on the screws. The PWM gain is set so the velocity is roughly equal to the commanded input. For example a PID output of 60 will give about 60mm/sec movement.
I have the P and D set up to be just under the oscillation point and following error is fairly low. Adding I increases stiffness when the machine is stationary but also increases the following error when moving. Even more strangely, the following error keeps increasing on long moves. It is almost as if I is working the wrong way round while moving. If I turn down I, the following error while moving is much less and it does not increase on long moves. Adding FF1 also increases the following error. So far the best results so far are with P=1200, D=10, everything else 0. Has anyone got any idea what is going on here? Les ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users