I have made huge strides on my Supermax conversion from an Anilam Crusador M to a 5i25/7i77. I was very happy to have the encoder resolution and motor/encoder directions setup so that I can start tuning. I was able to follow John Thornton's Velocity tuning instructions, but I have the almighty dither...
Specs for the system are West Amp Servo's w/ tach feedback and 0.01mm resolution glass scales connected to the 7i77. Has anyone been able to tune this system and remove the dither without an additional high-res encoder added to the system? I've read as much as I can, mostly on the forum and here are the options I've found. 1. Try to tune out the dither. PCW mentioned maybe add a touch of pid-bias or FF3 (need to add FF3 to PID comp). NOTE: I need to go and work this a little more, but not optimistic. 2. 7i87 for tach feedback, but PCW says you're still dead reckoning and w/ time you'll drift. (ie no velocity when idle). And, I didn't see any more about this after about January 2013. I wish this would work because it would be rather inexpensive for hardware. 3. External encoders on ball screws or back of motors. I've heard people mention it, but haven't actually read about someone being successful with it. 4. Higher resolution linear scales. Ok - I'm going for the jugular here, I found on Ebay some 1um renishaw linear encoders and scales from the same guy. I'm thinking I can get a discount and get 3 axes of 1um linear scales for $400. It's more than adding rotary encoders, but I think the futzing around and simplicity of the final solution is compelling. Also, I can remove (and sell) the glass scales, put the renishaw's in place and wire in. Suggestions? Thank you, Mark ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
