On 03/30/2017 04:04 AM, andy pugh wrote: > On 30 March 2017 at 04:11, Jon Elson <el...@pico-systems.com> wrote: >> Now, I am using ilowpass on a 2.6 install, possibly >> something has changed. > Nothing has changed since 2014 > https://github.com/LinuxCNC/linuxcnc/commits/master/src/hal/components/ilowpass.comp > > The whole component is only 2 lines of code: > > ;; > value += (in - value) * gain; > out = (int)(rtapi_s64)(value * scale); > > > Right. Jeff Epler wrote that for me at one of the CNC Workshops at Roland Freistad's place. It is so SIMPLE, I am having some trouble seeing how it could be the culprit, unless maybe given very wrong parameters.
Anyway, comparing the input and output from ilowpass should confirm that it is (or is not) causing the problem. I'm thinking there is a combination of a weak encoder output drive, electrical noise, maybe A<-> B crosstalk and the PPMC encoder counter is counting somewhat erratically. I think putting Halmeter on the encoder count output and then cranking the encoder known distances at varying speeds might quickly show this is happening. (or not...) Jon ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
