On Fri, 10 Jul 2009, Leslie Newell wrote: > Date: Fri, 10 Jul 2009 19:29:55 +0100 > From: Leslie Newell <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Subject: Re: [Emc-users] Hostmot2 homing > > Thanks Peter, > >> rate sample rate yet, but this could be tried by using the raw-write command >> in your HAL init file. With a 5I20, the encoder sample rate is 33 MHz, when >> the filter is on, 15 clocks are required to recognize an input (the ~.5 uSec >> above) If for example the sample rate were lowered to 3.3 MHz, those 15 >> clocks >> would now be ~5 usec, much better at eliminating PWM interference, and stil >> capable are reading encoder inputs up to ~400 KHz > > How would I go about doing that? I'll start playing with chokes and > other filtering first. I prefer to stop noise rather than trying to > account for it in firmware. However it would be useful as a fallback plan. > > >> If you disconnect one side of the differential inputs, that input will likely >> not work as differential inputs have a 130 Ohm termination resistor and >> enough >> hyteresis that they will not switch when only one input is driven. > > That is a pity. One of the great things about a balanced line setup is > that you can detect a broken wire. > >> There is no >> encoder fault detection, that is better left to FE and PID saturation detect. > > I am not convinced. For instance if the cable fails just as you stop of > while stopped, 'I' could easily drive the motor quite hard before any > fault is detected.
No, PID saturate can get that in 20 mS or less... > > Les > > ------------------------------------------------------------------------------ > Enter the BlackBerry Developer Challenge > This is your chance to win up to $100,000 in prizes! For a limited time, > vendors submitting new applications to BlackBerry App World(TM) will have > the opportunity to enter the BlackBerry Developer Challenge. See full prize > details at: http://p.sf.net/sfu/Challenge > _______________________________________________ > 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. ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/Challenge _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
