There are bidirectional versions of very similar parts....

On 8/9/2011 11:04 PM, PICdude wrote:
> Quoting Marcel Duchamp<marcel.duchamp@sbcglobal.net>:
>
>> Have you looked at the LTC6101 from Linear Technology?
> Had not, but now that I check why it did not come up on my digikey
> search, I am finding that "current sense amp" yields more results.
>
> This looks nice, though I have to figure out what it does for
> bi-directional current sensing.  Guessing for now that I'll need to
> use two simultaneously around a single sense resistor.  Will read the
> datasheet tomorrow.
>
>
>> One thing about sensors like this is that they exhibit errors due to
>> offset voltage which means that as your measured current drops toward
>> zero, the error goes to infinity.  You can possibly avoid this by always
>> loading your circuit with a known amount of current and then subtracting
>> that out of the readings.  The other thing is to use as large of a value
>> of sense resistor as is possible since a large measured voltage vs any
>> fixed offsets improves the accuracy as well.
> I'll be sending the output to a PIC, so compensating for offset can be
> done there.
>
>
>> You probably will have to figure out a way around the various sources of
>> errors as attempting to do analog measurements better than 1% over
>> temperature, line voltage, etc. quickly gets challenging.
> I can temperature compensate (same PIC measuring a temp sensor), but
> was looking for simplicity.  Not a big deal though.
>
> Cheers,
> -Neil.
>
>
>

--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.