On Sat, 18 Jul 2009, Leslie Newell wrote: > Date: Sat, 18 Jul 2009 22:04:47 +0100 > From: Leslie Newell <les.new...@fastmail.co.uk> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Hostmot2 homing > > Hi Peter, > > What is the default value for the filter? I found that a value of 1 > nearly sorted the problem. A value of 2 was pretty well rock solid. Just > to be sure I set it to 6 as my max frequency is well under 200kHz.
Default is 0x800 which gives divide by one (33 MHz for 5I20s) This allows the maximum count rates (~4 MHz with filter bit set, ~16 MHz with filter bit clear) > > I guess it is already on your to-do list but I would guess that it would > be well worth adding this as a parameter with a recommendation in your > docs to set it for as low a frequency as practical. Yes, that recommendation (and a description of the filter timing) is in the regmap file, but not in the Hostmot2 manual as the driver does not support setting QFilterRate as yet. > > Thanks, > Les > > > >> Well if the extra filtering of the TTL inputs helps, I would do the trick >> with >> raw-write to setup the filter time constant (the QFilterRate register at >> 0x3400). Currently the filter frequency is 33 MHZ which gives a 450 ns time >> constant: good for encoder count rates up to ~4 MHz, if the filter was set to >> divide by 8 (loaded with 6) you could still count up to 500 KHz but reject >> pulses up to 4 uSec long. You can divide the 33 MHz by up to 2049 (which >> _will_ be too slow, limiting your count rate to ~2KHz (filter on) or 10KHz >> (filter off) >> > > ------------------------------------------------------------------------------ > 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 > Emc-users@lists.sourceforge.net > 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
