On Wed, 1 Aug 2012 15:55:15 +0100, you wrote: >On 15 July 2012 18:21, Jon Elson <[email protected]> wrote: > >>> I am not privy to how the encoder module works internally, but it seems to >>> me that if a timestamp could be put on the base thread sample >> The software encoder component, Mesa encoder counters and the Pico Systems >> UPC controller all can do this. > >I just, on a whim looked at this. The software encoder contains: > 382 /* increment main timestamp counter */ > 383 timebase += period; > 384 /* done */ > >Now, I might be wrong, and need to check tonight, but I have more than >a sneaking suspicion that the "period" parameter passed to a realtime >function isn't the actual time elapsed since last invocation, but is >rather the rounded idealised value. >So, if you have a thread period of the same order of magnitude as the >thread dither, this might well introduce quite significant errors. >I think that ideally the timestamps would be CPU clocks, but that >would involve overhead.
Andy - further on spindles, as per Sam's suggestion I tried net spindle-position encoder.0.position-interpolated => motion.spindle-revs rather than net spindle-position encoder.0.position => motion.spindle-revs At low speeds with low encoder counts it sounded totally different - much worse with odd pauses :( I've not actually cut a thread with it, but for the same spindle speed I reckon the pitch would be off - it just doesn't seem to be driving the Z axis at the correct feed and looking at the Z axis velocity display on the gui, it's all over the place. Unfortunately I'm still on limited activities until I see the surgeon again next week, and on strict instructions not to lift anything heavy - wrong chuck is on lathe so couldn't actually cut something to prove it one way or t'other. Steve Blackmore -- ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
