Data Acquisition

Dear all,

I have to develop an application with the following basic requirements:
- 40 analog channels of Voltage/Current
- ADC with 16 bits of resolution
- at least 96 sample point per cycle (50 and 60Hz), which
  means 4800 and 5760Hz of sampling frequency
- simultaneous sampling of all channels

The main concern is data acquisition.

It is a like a data logger.

Since a lot of math must be performed per cycle using the acquired data, I
start looking for a DSP solution, but it is important to integrate with a
uC in order to provide further features of an embedded system, such as
keypad, LCD, Ethernet, GPIO, etc.

My question is: does any one knows a good start/development kit with good
availability of tools that integrate the ADC capabilities as mentioned
before? Or I have to start looking for separate ADC capabilities?

Thanks for your attention.

Best regards,

    Roger 

rogerdff wrote:
> I have to develop an application with the following basic requirements:
> - 40 analog channels of Voltage/Current
> - ADC with 16 bits of resolution
> - at least 96 sample point per cycle (50 and 60Hz), which
>   means 4800 and 5760Hz of sampling frequency
> - simultaneous sampling of all channels
> 
> The main concern is data acquisition.
> It is a like a data logger.
> 
> Since a lot of math must be performed per cycle using the acquired data, I
> start looking for a DSP solution, but it is important to integrate with a
> uC in order to provide further features of an embedded system, such as
> keypad, LCD, Ethernet, GPIO, etc.
> 
> My question is: does any one knows a good start/development kit with good
> availability of tools that integrate the ADC capabilities as mentioned
> before? Or I have to start looking for separate ADC capabilities?
> 
> Thanks for your attention.
> Best regards,  Roger 

If you can tolerate working in Labview and you don't need  
large quantities, you might want to consider NI's compactRIO.

http://www.ni.com/compactrio/

Lots of configuration, FPGA an option, 
trade-off is dev. time vs cost, (it ain't cheap).

On Aug 13, 11:47 am, "rogerdff" <roger...@hotmail.com> wrote:
> Dear all,
>
> I have to develop an application with the following basic requirements:
> - 40 analog channels of Voltage/Current
> - ADC with 16 bits of resolution
> - at least 96 sample point per cycle (50 and 60Hz), which
>   means 4800 and 5760Hz of sampling frequency
> - simultaneous sampling of all channels
>
> The main concern is data acquisition.
>
> It is a like a data logger.
>
> Since a lot of math must be performed per cycle using the acquired data, I
> start looking for a DSP solution, but it is important to integrate with a
> uC in order to provide further features of an embedded system, such as
> keypad, LCD, Ethernet, GPIO, etc.
>
> My question is: does any one knows a good start/development kit with good
> availability of tools that integrate the ADC capabilities as mentioned
> before? Or I have to start looking for separate ADC capabilities?
>
> Thanks for your attention.
>
> Best regards,
>
>     Roger

Hi Roger,

Have you considered adding a set of data aquisition cards to a high-
performance desktop PC? For example, maybe you could use four M-Audio
cards (http://www.m-audio.com/products/en_us/Delta1010LT-main.html,
$250 each) for data aquisition, though I'm not sure that this
particular card would meet your simultaneous sampling requirement -
but there are other ADC card options.

A modern PC may have the horsepower to do the DSP at your low sample
rates. There are DSP libraries that exploit the vector processing
units of Intel processors. Obviously, a desktop PC is not a hard real-
time system, but you may find it good enough, especially if you have a
way of flagging and recovering from input buffer overflows.

Darol Klawetter

First of all, thanks for the replies so far.

Actually, we need to develop a final product with all the embedded
hardware designed in a case: PCB for the controller and for the
input/output modules.

The NI solution is very interesting and fast, but as far as I could
understand I will have to start from "zero" to design the final hardware.

For this reason, it is important to start working with a development kit
that offers most of the needed devices.

The Labview is being considered to develop a prototype. A DAC board is
being considered to generate the analog signals (simulating a conditioned
signal) used for the ADC inputs. Then, the digitalized signal is going to
be fed (using SPI, Parallel, etc) to the controller.

For the controller, I have seen so far two options:
1. From Atmel, the DIOPSIS 940HF 
2. From TI,  the TMS320F3812
cause both combine DSP and uC.

For the ADC, I am looking for an evaluation board that offers
simultaneous
sampling for many channels (preferably as many as possible, since we need
at least 40 analog channels). So far, I found some options from TI:
- ADS8365, but uses parallel output
- ADS1178, that uses SPI

Since a lot of data is to be stored, it is also important to have at
least
16-32Mb of SRAM, and a higher mass storage media such as SD cards of
2-4GB.

Digital input varying from 24 to 250Vdc is also needed: at least 2 times
the number of analog channels, which means at least 80 DI. Again, for the
prototype, a DO board with Labview is being considered.

Digital output for alarm purposes is also considered.

Communications features (Ethernet, USB) is basic requirement, as it is
also a keypad, LCD, etc.

When the prototype with the "final" firmware is designed, then the final
PCB input modules together with the controller PCB will be developed. The
test will be carried out using a digital box capable to generate the real
analog values coming from the field: currents ranging from 1 to 20pu (1
pu
equals to 1 or 5A) and voltages ranging from 1 to 2pu (1 pu equals to 66
or
115V). 

But for prototyping, the ADC board and the controller are the critical
hardware components that I need to define until next week.

Well, that is the "architecture" we have envisaged so far. Any ideas are
welcomed.

Hope I was clear enough. Any other detail, please, just ask me.

Thanks again for all.