http://en.wikipedia.org/wiki/Signal_reflection
http://en.wikipedia.org/wiki/Signal_integrity
http://electronicdesign.com/communications/back-basics-impedance-matching-part-3
google about impedance matching, there's many info about it
2013/11/6 Roberto Spadim <[email protected]>
> maybe you have wrong impedance on the wire and the sensor is ok, try to
> equalize the impedance of this sensor wire
>
>
>
> 2013/11/6 Jeff Siddall <[email protected]>
>
>> On 11/05/2013 03:16 PM, Jeff Siddall wrote:
>> > On 11/05/2013 01:45 PM, Roberto Spadim wrote:
>> >> check the checksum statistics and check if you have short circuits bad
>> >> checksums and others problems
>> >
>> > Everything is zero in the BUS and CRC statistics except for:
>> >
>> > /statistics/errors/BUS_readin_data_errors: 65
>> > /statistics/errors/CRC8_errors: 16
>> > /statistics/errors/CRC8_tries: 30678
>> >
>> > Does anything stand out there?
>> >
>> > None of that appears to line up with the amount of bad data I am seeing.
>>
>> I believe I have discovered the issue with my temperature readings and
>> dropping devices. One of my DS1825s had a broken pin (AD0). It appears
>> when an address pin floats it can really mess up the bus. I took some
>> voltage readings and with that sensor connected the bus voltage was
>> erratic between 2.5 and 5 V.
>>
>> With that sensor removed the readings all seem normal again.
>>
>> Jeff
>>
>>
>>
>>
>>
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>
>
>
> --
> Roberto Spadim
> SPAEmpresarial
>
--
Roberto Spadim
SPAEmpresarial
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