On Fri, Mar 20, 2009 at 03:15:41PM -0700, richard harris wrote: > > I am running Elson's servo system and > EMC 2.2.6. > > Over the last few days I have run > several hundred parts single point threading a M22x1.5 threads > without a single bad thread. Yesterday I switched to cutting a > M20x2.5 and suddenly on ever other part the lathe will rapid during a > cut. I had a similar issues months back and upgraded EMC to 2.2.6 > and the issue went away. The lathe will go to the start the thread > it will do a brief pause for the index pulse and shoot off at G0 > through the part. I went back to my M22 code and ran 30 parts > without fail, I even reduced the spindle speed to what I am cutting > the M20 at thinking I might get more noise from the VFD at the lower > end of the rpm band and no effect. I also increased the number of > passes on the M22 program to replicate the M20 program and no > failures.
I looked here http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Released and do not see any relevant changes in PPMC since July 2007. This smells like an index problem. The thing that can cause it is when, due to a driver bug, the driver reports an index pulse has occurred but it doesn't reset its count. PPMC had this problem in 2007 but it is long since fixed to the best of our knowledge. MAYBE there is still one more bug lurking in this driver. Your task now is to capture the failure on halscope and do a screen grab showing what happens. You should plot ppmc.0.encoder.xxx.position, ppmc.0.encoder.xxx.count, and ppmc.0.encoder.xxx.index-enable. You should probably trigger on the index-enable. Chris ------------------------------------------------------------------------------ Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are powering Web 2.0 with engaging, cross-platform capabilities. Quickly and easily build your RIAs with Flex Builder, the Eclipse(TM)based development software that enables intelligent coding and step-through debugging. Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
