Use a 12-bit ADC - Githubissues

PaxInstruments / t400-electronics

Electronics for the Pax Instruments T400 temperature datalogger

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Use a 12-bit ADC #34

Closed charlespax closed 10 years ago

charlespax commented 10 years ago

Is it possible to use a 12-bit ADC with software to achieve the desired accuracy and resolution?

charlespax commented 10 years ago

Suggestions made to me:

Get a faster 12 bit one (and possibly use an external multiplexer)
Lower the reference voltage so the 12bit resolution is in the lower voltage range, thus giving a better uv resolution per bit

charlespax commented 10 years ago

Take a look at this app note http://www.cypress.com/?docID=46585

charlespax commented 10 years ago

The whole K-type thermocouple range is about 60 mV. 60 mV / 2^12 = 0.01465 mV/LSB.

cibomahto commented 10 years ago

Just out of curiosity, what's the reason for the change? Price? Current draw?

If the ADC has a gain multiplier (like the current one), increasing the gain will also help improve the resolution, albeit with some small noise from the amplifier.

charlespax commented 10 years ago

I was just adding notes from a conversation. Not looking to change anything at this point.

charlespax commented 10 years ago

For the T400 we will stick with the MCP3424. This question should be answer if a future device requires measuring a thermocouple.