On Tuesday 28 November 2006 21:41, Chris Radek wrote: > Have you also observed these incorrect direction changes > on halscope hooked to the parport pins (at the HAL > level)?
Nope... I figured the first thing you'd ask is whether I could hitch up a real scope and verify the actual pins. In any event, I'm an oscilloscope kind of guy and don't trust this software-monitoring-software stuff. HALscope can capture only the leading edge of a move, because I must set it to sample at the BASE_PERIOD rate in order to capture the step pulses. Alas, the post-trigger half of the buffer doesn't have enough samples for anything but the shortest of moves, much shorter than a doink on the keyboard. I think the "Multiplier" setting should solve that, but the up-down arrows are grayed out and changes to the numeric value don't stick. Evidently, the Lords of Cosmic Jest have taken an interest in this project, as I can't get it to fail this morning. My esteemed wife, who spent many years doing software testing, reminds me that this is typical behavior. I set up both HALscope and the real 'scope to monitor the Z axis, loaded the cam milling code (with the mill disconnected), and will let it run. [time passes] Worked perfectly, of course. Wish I had the mill running, I might have gotten a good cam out of the deal. That suggests turning on the HALscope thread futzes with the timing just enough that the direction-setting code either won't misbehave or misbehaves -much- less often. I did, however, see one anomaly. The cutter moves upward at one point during the milling and the direction signal went high - low - high before the step signal started, on both the HALscope and the real 'scope. It was up for 1 ms, down for 1 ms, then back up again. About 25 ms later, the step pulses began ramping up for the Z axis move. That would not have caused a motion error, because no step pulses occurred during the direction glitch, but it's the same type of misbehavior as when the problem occurs. Another datum that may help. The errors tend to accumulate as though the direction signal were erroneously low. I have seen a few high glitches, but the tendency is definitely the other way. The bad bit doesn't come from the Great Zero Ocean, but that's the way to bet. [time passes] AH-HA! Caught one! Manual jog toward -X. The direction signal went high for 2 ms, low for 11-ish, then high again. The first step pulse is smack in the middle of the low glitch; it's the first of many that appear to be ramping up normally for the X axis move. Screen shot attached. I think it'll get scrubbed from the bulk list, but the CC to Chris should work. I vaguely recall that something like this was corrected a while ago, but don't remember the details. I'll try returning to 2.0.0, but it'll be a while before I have anything more to relate: some -real- work's gotta get done before I can play in the shop again! Onward... -- Ed
Direction glitch.png
Description: PNG image
------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
