On Thu, 2008-10-23 at 10:36 -0400, Dave Keeton wrote: > I think that using Modbus to operate a vfd for spindle control is ok, > but again the discussion is going back to issues of timing critical > functions such as motor and drive control. ... snip > Dave
I agree that Modbus should only be used for non-reatime functions, but I didn't see anyone suggest to the contrary in the recent posts. I did try to imply that whatever HAL component is written needs to do what it needs to do within the time available in the thread that it lives in. I had trouble with my SPI component due to this. I think just about everything you would want to with spindle speed and most other I/O can be done in non-realtime. This reminds me that there is a time critical element in ModBus in that the spec calls out timing constraints on the ACK or RTS or some such thing. It seemed that experts disagree to how handle the timing issues. Kirk ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
