On Tue, 6 Aug 2013, andy pugh wrote: > Date: Tue, 6 Aug 2013 22:23:35 +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 19:47, Peter C. Wallace <[email protected]> wrote: > >> Looks like 64X or 32X would be the maximum interpolation ratio without using >> a >> higher mux frequency. 256X requires an equivalent counting frequency of about >> 8MHz. This is out of the range of muxed encoders. > > Are you basing that on the max frequency of the chip? > > This was what he said: > "Sounds like we're way off the limits in terms of count capability of the > 7i77. > "transition distance" is set to 0.77 us > Even at rapid of 2000 mm/min, we're only at 0.85333 Mhz into the 7i77 and > 3.3 khz into the interpolator"
A.8853333 MHz signal is a 3.41 MHz count rate, right at the 7I77s limits. If you set the transition distance to .77 usec, the maximum count rate will be 1.3 MHz so you will lose counts above 666 mm/min. > > -- > 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
