> Could you provide an example of a servo motor with feedback? I will try, but all my machines are stepper driven, so while I think I understand the concept of a servo drive I've never tuned one or worked with it directly. Feel free to correct any misunderstandings. I'm using arbitrary dimensions for the sake of example.
Controller: set X velocity to 0.1 Drive: X velocity 0.1, position 0 Drive: X velocity 0.1, position 0.05 Controller: set X velocity to 0.2 Drive: X velocity 0.2, position 0.1 Controller: set X velocity to 0.1 Drive: X velocity 0.1, position 0.2 Drive: X velocity 0.1, position 0.25 Controller: set X velocity to 0 Drive: X velocity 0, position 0.3 For synchronous motor drive the feedback would need to be velocity and spindle angle and position. snip >If you include feed override, especially >adaptive feed override (which runs in realtime, and is >intended to be >used for things such as EDM and plasma machines), >then you make it >impossible to use a non-realtime communications >scheme Basic feed override is easy-the new block is sent to the drive with a new rate or velocity. A rapidly changing rate override will require a number of packets. Adaptive would be a bit harder because it would require synchronized input. ACN is designed for realtime control. It does this through sequencing rather than time domain multiplexing. Either strategy does have a maximum bandwidth. Sequencing has a higher potential bandwidth, but the maximum will vary based on the load. The drive will have to use a time domain software loop, but as long as the sequenced messages arrive faster than the loop cycle time it will not affect the synchronicity of the system-messages arriving before they are needed just get saved for the next cycle. With 10-BaseT this could cause problems, but 100-BaseT should be OK. In practical application the protocol layer will self-synchronize with the software loop in the drive, since controller actions depend on feedback. snip >>Advanced controllers are a more involved discussion. >> >> > Arbitrarily advanced, you could say :) We could of course stick a > mini-EMC2 on each controller ... That is what makes arbitrarily advanced controllers a more involved discussion. :) How much of EMC2 to put in the drive, porting issues to microcontrollers with various architectures, these could be loooooong discussions. We started working on ACN around 1998. It was published in 2006. Embedded EMC2 (EEMC2? E squared MC2? the latter sounds like a formula...) is definitely worth discussion, I just didn't want to start there. Thanks, Javid ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
