Re: PC104das16jr/16 and MUX counter problem

From: John Conner <conner_at_empiredi.com> · Date: Sun, 16 Jun 2002 21:41:23 -0600

Looking at the samples, I don't think it is the MUX.  Looks like the channels 
are open circuits.  But you say they are grounded.  You might try replacing 
the
load cell with a simple voltage source and apply it to various channels.  
Another
thing to try would be a second DAS16 if you have one.  Do check the grounding 
of the unused channels.  

John 

> Hi Frank,
> 
> here is what our data looks like:
> 
> 0 0 0 0 0 0 0 0 0 0 0 0 0 7232 0 0=20
> 0 0 0 0 0 0 0 0 0 0 0 0 0 7227 0 0=20
> 0 0 0 0 0 0 0 0 0 0 0 0 0 7982 3689 =20
> 0 0 0 0 0 0 0 0 0 0 0 0 0 8045 3700 1149=20
> 350 0 0 0 0 0 0 0 0 0 0 0 0 8509 3954 1245
> 296 0 0 0 0 0 0 0 0 0 0 0 0 9234 2986 1342
> 0 0 0 0 0 0 0 0 0 0 0 0 0 8123 3509 1454
> 0 0 0 0 0 0 0 0 0 0 0 0 0 7503 3216 0=20
> 0 0 0 0 0 0 0 0 0 0 0 0 0 7217 0 0=20
> 0 0 0 0 0 0 0 0 0 0 0 0 0 7427 3074 0=20
> 0 0 0 0 0 0 0 0 0 0 0 0 0 8177 3200 1234=20
> 0 0 0 0 0 0 0 0 0 0 0 0 0 7219 3326 0=20
> 0 0 0 0 0 0 0 0 0 0 0 0 0 7145 0 0=20
> 0 0 0 0 0 0 0 0 0 0 0 0 0 7215 234 0
> 0 0 0 0 0 0 0 0 0 0 0 0 0 7214 115 0=20
> 0 0 0 0 0 0 0 0 0 0 0 0 0 7207 345 0=20
> 0 0 0 0 0 0 0 0 0 0 0 0 0 7223 216 0=20
> 
> When we increase the weight on our load cell, more and more channels get=20
> involved. The output looks almost like the output of your cmd program, th=
> ough=20
> we only use a simple program that only reads data from every channel. Do =
> we=20
> have a hardware problem with our MUX ? John told me that cutting cntr2 ou=
> t=20
> line on the cable might solve the problem, but we didn`t try yet. Or is i=
> t=20
> probably a grounding problem ?
> The other problem we`ve got is that the data on channel 14 varies pretty =
> much,
> even if there is no weight on the load cell..the data here should be more=
> =20
> constant.
> 
> Daniel
> 
> > Can you send a couple lines of data so I can see exactly what you mean =
> by
> > 'scattering'?
> >
> > Frank
> >
> >
> >
> > _______________________________________________
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> > comedi_at_stm.lbl.gov
> > http://stm.lbl.gov/cgi-bin/mailman/listinfo/comedi
> 
> --=20
> ----------------------------------------------------------------------
> "Schlage die Trommel und f=FCrchte dich nicht" (Heinrich Heine)
> 
> Daniel Koch (danielkoch_at_gmx.net)
> 
> 
> 
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