On Tue, 6 Aug 2013, andy pugh wrote: > Date: Tue, 6 Aug 2013 18:14:11 +0100 > From: andy pugh <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Subject: Re: [Emc-users] A puzzler > > On 6 August 2013 18:02, Stuart Stevenson <[email protected]> wrote: >> If the scale is off that far you may want to exchange it for a correctly >> functioning scale. > > I think the question is how to isolate the problem. > Between the scale, the interpolator, the 7i77, 7i25, LinuxCNC and PID > controller there is quite a lot that could be wrong.
Do you have the interpolator specifications? some have quite large quadrature distortion (large deviations from 90 degree phasing) which may cause the 7I77/5I25 to lose counts. Also is the encoder filter on or off? With filter on and standard Mux frequency (4.1666MHz), pulses less than 1.8 uSec (15 counts at 8.13333 MHz) will be ignored. This is a 1.111 MHz max count rate assuming perfect quadrature. With filter off, pulses less than 360 nS (3 counts at 8.13333 MHz) will be ignored. This count rate is limited by multiplexing to 4.16MHz assuming perfect quadrature. The multiplex rate can be increased to raise these count rates but this will require a raw-write to the muxed qcounter filter rate +deskew register (you would need to the 5I25-7I77 cable length for the proper de-skew setting) > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > ------------------------------------------------------------------------------ > Get 100% visibility into Java/.NET code with AppDynamics Lite! > It's a free troubleshooting tool designed for production. > Get down to code-level detail for bottlenecks, with <2% overhead. > Download for free and get started troubleshooting in minutes. > http://pubads.g.doubleclick.net/gampad/clk?id=48897031&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with <2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
