I can only imagine. It's the test jib that Technologics uses to calibrate the
ADC. And the voltage is being measured fine -- it's just that it's measuring
the wrong channel. I'm guessing that there's More Magic needed when switching
the ADC to a different channel.
________________________________________
From: on behalf of Joel
Morgan
Sent: Tuesday, March 08, 2011 6:50 PM
To:
Subject: RE: [ts-7000] TS-7400 EP9302 ADC channel switching
On Tue, 2011-03-08 at 18:39 +0000, Russell N. Nelson - rnnelson wrote:
>
> No, I'm using the TS-9441, which presents 0.85 volts and 2.5 volts on
> even and odd pins.
Is that a low impedance source?
> ________________________________________
> From: on behalf of
> Jason Stahls
> Sent: Tuesday, March 08, 2011 1:09 PM
> To:
> Subject: Re: [ts-7000] TS-7400 EP9302 ADC channel switching
>
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On 03/08/11 12:54, Russell N. Nelson - rnnelson wrote:
> > I'm having trouble reading two ADC channels in quick succession, or
> even in slow succession. Values from one channel bleed over into
> another channel. And it's not just my code, it's also the
> Technologics' test7400ADC. If you run it like this:
> >
> > while ./test7400ADC; do echo -n ''; done
> >
> > then sooner or later it craps out, and when it does, it prints a
> value that clearly came from a different channel. I've tried reading
> twice and discarding the first. inserting a 100ms delay betweeen these
> two reads, and it still happens. How can I fix this? I need to measure
> both voltage and current consumed, and I have the two sensors hooked
> up to ADC channels.
>
> I don't mean to be condescending, but are you sure it's not a
> interface
> issue? If you have any de-coupling caps or opamp buffers not biased
> right ect it could bleed over due to induction. So does the reading
> you
> get from the ADC match a scope/meter on the same lead?
>
> - --
> Jason Stahls
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--
--
Joel R. Morgan
Morgan Millwright Services, Inc.
Linux User #504110 http://counter.li.org/
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