I need a DAQ

[cncjerry]

More like a want one.  I've been looking at some of the new Analog devices boards and the AD4110 and the Analogmax daq1.
Both just don't do it for me.  I thought the Ad4110 eval was decent at $99 USD but then I guess you need the system development platform board I think it is called, the interface between the board and PC,  and that is another $50.
Then I started looking at the Hantek products and Picoscope, Analog Discovery and other products like those.  I posted here because the application would drive the need. I don't need it to generate anything as some of those units have signal generators.  I would like it to be 24 bit and sampling needs to only be 100 per second though faster is ok.  I can live with 20 bits. I don't need fancy software as all the processing is offline.  Ideally I want to hook my lab freq reference to it and an external voltage reference. I thought about building my own like the AD4110 and might still go that route.  It will be used for time and phase related experiments initially, measuring some very low frequency and phase differences. I saw that Owon 6112
and that looked interesting with averaging and ET it looked like it got to 13bits only.

Thoughts?
 

[DaJMasta]

A DAQ or an ADC?


There are a number of USB DAQs in various configurations, but if you want 20 bits at 100 samples a second..... you just need a decent DMM.  Something like a 6.5 digit DMM should give you around that without PLC averaging and reading to memory or over an external interface can probably get you 100 samples a second.  A Keithley 2000, for example, can be pretty cheap on the used market and can give you 5.5 digits of resolution to about 270 samples a second over GPIB.


If you relax your number of bits requirement a bit, NI or Measurement Computing both make 14-16 bit USB DAQs with several channels and much higher sample rates, then many other companies make similar products (I think Dave's even showed a couple on the mailbag).  There's also the PXI or similar mainframe option if you're willing to invest in a chassis and controller as you can get high sample rates, high resolution, or both for relatively reasonable prices, and there's availability for many measurement channels at once.


On the cheap end of things, if you can limit your input signal range, audio ADCs are commonly 24 bit with 96kHz or more sample rate and are very cheap as consumer items.  With the right input circuitry to keep it within range and with a decently laid out commercial board, you can achieve some pretty low noise and high accuracy with your regular audio card as an input.

[thm_w]

https://www.picotech.com/data-logger/adc-20-adc-24/precision-data-acquisition
https://labjack.com/All-Categories/24bit-analog-input-daq