Can Measurement Computing USB1208FS DAQ be used for data acquistion Real Time application?

I'm designing a PID controller for the Flow Control and I'm using two MCC USB1208FS DAQ for input and output of the controller to the real plant. My first question is whether is it possible to use DAQ Toolbox for real time application?

If not, then how to use them in Real Time application for analog input and analog output?

TQ

Answer 1

[Walter Roberson]

It is not practical to use any USB based device for real-time applications unless your time requirements are fairly generous. Because USB is a shared bus packet-based design that relies upon time-slots, USB has inherent latencies that are often too high for real-time systems.

The USB based DAQ that I have encountered work as virtual serial ports. When virtual serial ports are used in USB, the minimum latency is 40 ms per output packet (unless a full-sized USB packet is written, or unless you can tell the USB controller to send earlier -- which is not a possibility that the toolboxes appear to support.)

I do not have any information at the moment about MATLAB Coder or Simulink Coder support for the MCC USB1208FS DAQ (i.e., for use on a stand-alone Real Time Operating System); MATLAB itself as a product is not able to handle real time work, especially not on MS Windows. I do not happen to have time at the moment to research the Coder support.

[Walter Roberson]

For a more detailed exploration of real-time USB, please see http://www.mathworks.com/matlabcentral/answers/10386-how-to-import-a-continuous-signal-from-usb-6009-to-an-oscilloscope-daq-toolbox

Answer 2

[Kaustubha Govind]

Walter's response details the limitations of using MATLAB directly for real-time processing. However, it appears that the Data Acquisition Toolbox does support MCC USB 1208FS: http://www.mathworks.com/products/daq/supportedio14004.html#USB

I do not see any USB devices listed under supported hardware for the MathWorks products that are best suited for real-time processing: xPC Target and Real-Time Windows Target.