Sparratic data
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I just connected an Analog devices ADXL311 accelerometer to my BS2 through a
LTC1298 ADC, however i've found that i get seemingly random data outputs when
run according to the specifications of both IC's. What could be causing this?
Thanks,
Christian T. Wentz
LTC1298 ADC, however i've found that i get seemingly random data outputs when
run according to the specifications of both IC's. What could be causing this?
Thanks,
Christian T. Wentz
Comments
writes:
> I have the circuit running off battery supply, and the LTC seems to work
> fine by
> itself - the capacitors are as recommended by Analog Devices, but maybe i'll
> try using capacitors for a different bandwidth and see how that goes.
>
If your ADC is like my ADC, you should have a .1ufd bypass on each ADC input
pin, and a 1.2K resistor in series with the ADC input. Works wonders for
stability.
Sid
[noparse][[/noparse]Non-text portions of this message have been removed]
Run off a battery to cancel out power supply affects....
Original Message
From: "Christian T. Wentz" <cwentz@m...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, July 20, 2004 2:20 PM
Subject: [noparse][[/noparse]basicstamps] Sparratic data
> I just connected an Analog devices ADXL311 accelerometer to my BS2 through
a
> LTC1298 ADC, however i've found that i get seemingly random data outputs
when
> run according to the specifications of both IC's. What could be causing
this?
>
> Thanks,
>
> Christian T. Wentz
>
>
> To UNSUBSCRIBE, just send mail to:
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>
Do you have the right capacitors on the ADXL?
What happens if you disconnect the ADXL from the LTC?
Does the shiftin/shiftout and CS high/low for the LTC work as it should?
(software).
I would try to get the LTC working properly first. Then afterwards connect
the ADXL.
Succes,
Klaus
Original Message
From: "SB" <steve.brady@r...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, July 21, 2004 12:12 AM
Subject: Re: [noparse][[/noparse]basicstamps] Sparratic data
> Noise?!
> Run off a battery to cancel out power supply affects....
>
>
Original Message
> From: "Christian T. Wentz" <cwentz@m...>
> To: <basicstamps@yahoogroups.com>
> Sent: Tuesday, July 20, 2004 2:20 PM
> Subject: [noparse][[/noparse]basicstamps] Sparratic data
>
>
> > I just connected an Analog devices ADXL311 accelerometer to my BS2
through
> a
> > LTC1298 ADC, however i've found that i get seemingly random data outputs
> when
> > run according to the specifications of both IC's. What could be causing
> this?
> >
> > Thanks,
> >
> > Christian T. Wentz
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject
and
> Body of the message will be ignored.
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>
>
>
itself - the capacitors are as recommended by Analog Devices, but maybe i'll
try using capacitors for a different bandwidth and see how that goes.
Quoting SB <steve.brady@r...>:
> Noise?!
> Run off a battery to cancel out power supply affects....
>
>
Original Message
> From: "Christian T. Wentz" <cwentz@m...>
> To: <basicstamps@yahoogroups.com>
> Sent: Tuesday, July 20, 2004 2:20 PM
> Subject: [noparse][[/noparse]basicstamps] Sparratic data
>
>
> > I just connected an Analog devices ADXL311 accelerometer to my BS2 through
> a
> > LTC1298 ADC, however i've found that i get seemingly random data outputs
> when
> > run according to the specifications of both IC's. What could be causing
> this?
> >
> > Thanks,
> >
> > Christian T. Wentz
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject and
> Body of the message will be ignored.
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
> Body of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>
>
>
Christian T. Wentz
BUT, we did run a LONG data line out of p16 and found that I had to add an
RC filter to clean it up enough to be ingested properly.
but narrowing your bandwidth should help.
I don't know about a pull (up/down) resistor in your application.
Is it giving bad readings BETWEEN readings? or is the noise actually in the
data?! Not sure if that makes sense....basically that the Signal to noise
ratio is good enough for the actual data, but when the data is absent the
noise causes false data....
Have you tried disconnecting power to the ADXL (but leaving it connected to
the LTC)? I like working backwords like this....remove power to a device --
problem persists?....then remove data lines (like mini antennas) -- problem
persists? Ground unused inputs -- problem persists? RC filter....cap to
ground....
This takes me to the stamp....I doubt your noise is here...more likely at
the LTC.
You working under a flourescent lamp? Near an electric field? You drying
your hair while working on stamps?? lol
how long is the wire run between the ADXL and your LTC??
Original Message
From: "Christian T. Wentz" <cwentz@m...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, July 20, 2004 7:39 PM
Subject: Re: [noparse][[/noparse]basicstamps] Sparratic data
>
> I have the circuit running off battery supply, and the LTC seems to work
fine by
> itself - the capacitors are as recommended by Analog Devices, but maybe
i'll
> try using capacitors for a different bandwidth and see how that goes.
>
>
>
> Quoting SB <steve.brady@r...>:
>
> > Noise?!
> > Run off a battery to cancel out power supply affects....
> >
> >
Original Message
> > From: "Christian T. Wentz" <cwentz@m...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Tuesday, July 20, 2004 2:20 PM
> > Subject: [noparse][[/noparse]basicstamps] Sparratic data
> >
> >
> > > I just connected an Analog devices ADXL311 accelerometer to my BS2
through
> > a
> > > LTC1298 ADC, however i've found that i get seemingly random data
outputs
> > when
> > > run according to the specifications of both IC's. What could be
causing
> > this?
> > >
> > > Thanks,
> > >
> > > Christian T. Wentz
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@yahoogroups.com
> > > from the same email address that you subscribed. Text in the Subject
and
> > Body of the message will be ignored.
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject
and
> > Body of the message will be ignored.
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
>
>
> Christian T. Wentz
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
> Yahoo! Groups Links
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>
>
>
>