How to choose an ADC?

Hi, Jose,

it sounds like you need a general purpose ADC, let me move your post to our precision analog e2e.

-d2

Hi :) Don Dapkus !!!! I am agree!! tank you so much.

I Hope it give good results. 

I'm beginer about AD converters  and i need suport 

Ihope ou have a good day :)

Hi Jose,

What sampling rate or data rate are you looking for? For load cells, this usually does not have to be very fast. Most often load cells are paired with delta-sigma, aka oversampling, converters, to measure at a higher resolution.

Regards,
Chris

Jose,

As Chris has mentioned there are several variables that are a part of choosing the correct dataconverter.  Some possible choices for load cells are ADS1230 (20-bit), ADS1232 (24-bit), ADS1131 (16-bit) and ADS1231 (24-bit).  All of these devices are hardware configurable and communicate to the microcontroller using SPI protocol.  These devices have reference designs and also the datasheets show typical connections for using load cells.

Best regards,

Bob B

Hi!! Chris and Bob !!!!! tanks so much for your reply and your time.

my troble is that the load cell most supports fatigue cycles of tension and compression  around 60Hz to tests samples of metal (Im working for choose a load cell whit that feature ).

I wonder with 1 MSPS that could cover those needs. do you thing whit that sample rate would be enough?

or all those devises which kindly Bob have recommended me can help me?

I tried acquiring a 60Hz  sine waveform whit the pic (ofcourse firts it was conditioned ) and the result was poor in LabVIEW.

best regards I hope you have a good day.

jesus.

Hi Jose,

The devices I mentioned are for measuring a single measurement very precisely and the data rate is very slow.  If I understand you correctly, you are applying strain to a metal and flexing the metal back and forth at 60 Hz.  Correct me if I'm wrong with my understanding.

If the rate of change is 60 Hz, then by Nyquist you need to sample at least twice the frequency of interest.  You might want to take a look at the ADS1246, which can sample at higher data rates than I specified earlier.

If you give us the specific load cell you want to use, we can be a little more specific on devices.  1M sps dataconverter could possibly work with the right amplifier stage and anti-aliasing filter. However, this seems to be a little extreme as I think precision and low noise are probably greater factors than speed.

Best regards,

Bob B

Hi Bob :)tanks for yor time

It's Something like that. instead to flexing the metal. the metal is compressed (-> ------ <- ) and then stretched (<- ----- ->) .

sorry by the diagrams!! and I forget  mention that the test can be made whit a sweeping from to 1 Hz to 60Hz.

OMG!  thanks so much.  I didn't know about the noise you are right !!

I wonder with the instrumentation amplifier the noise is canceled I'll see the device you mentioned .

about the load cell I have thought make it firts.

A wheastston bridge  whit  a  strain gage made of constantan  and then buy a load cell 

how about this? do you think is enough whit just strain gage?

 best regards!!!! Bob.
 

Hi Jose,

Sounds like an interesting project.  You should be able to measure the strain as mentioned with a strain gauge in a wheatstone bridge configuration.  One other ADC you could look into is the ADS1256.

Best regards,

Bob B