Thanks for the help, guys. 20,000 counts per revolution is in fact pretty high for an encoder. The "latest thing" however is the new sin/cos encoders which output counts in the millions. http://www.engineeringtalk.com/news/enc/enc109.html I originally thought the video card might be the problem source so I replaced it last week (and lowered the period to .0001) but the problem still remains. My next step is to make an attempt at recompiling without the debounce code. I have *some programming experience but a duffer's guide on this would be great! Really, any instructions or recommended reading you could suggest would be appreciated. Regards, Craig *-----Original Message----- *From: [email protected] [mailto:bdi4emc-help- *[email protected]] On Behalf Of bdi4emc-help- *[email protected] *Sent: Friday, November 24, 2006 3:00 AM *To: [email protected] *Subject: Bdi4emc-help Digest, Vol 10, Issue 4 * *Send Bdi4emc-help mailing list submissions to * [email protected] * *To subscribe or unsubscribe via the World Wide Web, visit * https://lists.ourproject.org/cgi-bin/mailman/listinfo/bdi4emc-help *or, via email, send a message with subject or body 'help' to * [email protected] * *You can reach the person managing the list at * [email protected] * *When replying, please edit your Subject line so it is more specific *than "Re: Contents of Bdi4emc-help digest..." * * *Today's Topics: * * 1. Re: X-Axis Display Problem (David Szakovits) * 2. Re: X-Axis Display Problem (Paul) * * *---------------------------------------------------------------------- * *Message: 1 *Date: Thu, 23 Nov 2006 11:43:13 -0500 *From: David Szakovits <[email protected]> *Subject: Re: [Bdi4emc-help] X-Axis Display Problem *To: "Help and advice for BDI-4 users." * <[email protected]> *Message-ID: <[email protected]> *Content-Type: text/plain; charset=ISO-8859-1; format=flowed * *i am not sure that i am not seeing the same sort of thing. i definitely *get some freezing. i have been warned about the on board video that i *have and i am going to buy an AGP card to see if that might fix the *symptom but being a emc-novice, i do not know what to expect or if it *will fix the problem or if at all related. *djs * *Craig Gadd wrote: * *>Hello Paul, *> *>I'm having a problem with my BDI setup and was hoping that you might have *>some advice on a problem I have. I'm running BDI 4.51 with a Motenc Lite *>Card installed. The card is connected through a 50 pin ribbon cable to a *>Vital Systems breakout board which in turn has been wired to a single *>encoder which has 20,000 quad/cts per revolution). *> *>When I launch the generic.run, or emc.run things seem to behave normally *>with the units showing for the axis which has the encoder on it. The *units *>will update if I turn the motor slowly, and everything seems to work. *When *>I spin the motor quickly however, the unit display of the axis seems to *>"freeze" and will not recover. The rest of the interface continues to *>function properly though. Any ideas on what might cause this and how I *>might fix it? I've tried Tkemc,Xemc, and mini but they all seem to behave *>the same. *> *>Thanks, *> *>Craig *> *> *> *>_______________________________________________ *>Bdi4emc-help mailing list *>[email protected] *>https://lists.ourproject.org/cgi-bin/mailman/listinfo/bdi4emc-help *> *> *> * * * *------------------------------ * *Message: 2 *Date: Thu, 23 Nov 2006 17:51:41 +0000 *From: Paul <[email protected]> *Subject: Re: [Bdi4emc-help] X-Axis Display Problem *To: [email protected] *Message-ID: <[email protected]> *Content-Type: text/plain; charset="iso-8859-1" * * *Hi Craig * *On Thursday 23 November 2006 06:52, Craig Gadd wrote: *> The card is connected through a 50 pin ribbon cable to a *> Vital Systems breakout board which in turn has been wired to a single *> encoder which has 20,000 quad/cts per revolution). * *That is a pretty high resolution encoder ! * *> When I launch the generic.run, or emc.run things seem to behave normally *> with the units showing for the axis which has the encoder on it. The *units *> will update if I turn the motor slowly, and everything seems to work. *When *> I spin the motor quickly however, the unit display of the axis seems to *> "freeze" and will not recover. The rest of the interface continues to *> function properly though. Any ideas on what might cause this and how I *> might fix it? * *Many years ago, Fred Proctor (as I recall) was having problems with erratic *encoder counts and added a routine to "debounce" the input - This is hard *coded with an arbitrary limit of 10 times the max velocity. When the rate *of *change per servo cycle ecceeds this limit, any further input is ignored and *a *following error *should be triggered. * *With a 20,000 count/rev encoder and a moderate max velocity, I would *imagine *it would be quite easy to trigger the debounce routine - When you come to *connect the servo amps up and tune the system, as long as you don't go over *the top on the acceleration settings, you shouldn't experience any *problems.. *If you do, we can disable the debounce routine easily enough by *adding -DSIMULATED_MOTORS to the RTFLAGS of src/Makefile.inc.in and *recompiling vitalmod.ko * *If you need a step by step duffer's guide to setting up a build environment *and recompiling the kernel modules, just ask. * * *BTW With any servo system there is nothing to be gained by setting the *BASE_PERIOD parameter anywhere near what you might use with a stepper *system. *0.00005 or 0.0001 should be fine. * * *Regards, Paul. * * * *------------------------------ * *_______________________________________________ *Bdi4emc-help mailing list *[email protected] *https://lists.ourproject.org/cgi-bin/mailman/listinfo/bdi4emc-help * * *End of Bdi4emc-help Digest, Vol 10, Issue 4 ********************************************