Problems using "digitalio" with National Instruments NI 9401 CompactDAQ-Modul

Hey together!

I have some problems using "digitalio" with National Instruments NI 9401 CompactDAQ-Modul. I am working on Win XP (32 bit) and want to create a digital output with matlab.

I do like described in the help... When I type:

daq.getDevices

I get: Data acquisition devices:

index Vendor Device ID          Description          
----- ------ --------- ------------------------------
1     ni     cDAQ1Mod1 National Instruments NI 9211
2     ni     cDAQ1Mod4 National Instruments NI 9201
3     ni     cDAQ1Mod6 National Instruments NI 9263
4     ni     cDAQ1Mod8 * National Instruments NI 9401
* Device not recognized and may require additional configuration information.

I don't know, why the last device (what I want to use) is not recognized.

So when I type:

dio = digitalio('nidaq','cDAQ1Mod8');

I get an error message:

??? Error using ==> digitalio.digitalio at 117
The specified device ID is invalid. Use DAQHWINFO(adaptorname) to
determine
valid device IDs.

Could anyone imagine why?

Answer 1

[Chirag Gupta]

So basically, you need to follow either of the 2 examples:

Generates data in the foreground: http://www.mathworks.com/help/toolbox/daq/bsob84e-1.html#bsob867-1

Generates data in the background: http://www.mathworks.com/help/toolbox/daq/bsob84e-1.html#bsob885-1

With analog output, you can formulate your signal, queue it and start analogoutput.

For a step signal, something like:

dataOut = zeros (1,1000);
dataOut(1:200) = ones(1,200)*4.5;

s = daq.createSession('ni');
s.Rate = 1000
s.addAnalogOutputChannel('cDAQ1Mod2',0,'Voltage')
s.queueOutputData(dataOut);
s
s.startForeground();

This will generate a step for 0.2 seconds. You could use continuous generation to reuse the data to continuously generate the same signal.

[Randy82]

Hey Chirag,

another problem occurs on using your example:

There is the Error-Message "The data argument must contain one column for each output channel in the sesssion"

What could be the reason?

[Chirag Gupta]

Hi Andreas, you might have required to transpose dataOut.

Answer 2

[Laura Proctor]

This statement is because the NI 9401 device is not supported.

Here is a list of supported hardware for Data Acquisition Toolbox.

Answer 3

[Chirag Gupta]

To add on more to Laura's answer:

Data Acquisition Toolbox supports CompactDAQ only with its new session based interface.

Currently in MATLAB R2011a, the session based interface supports various analog inputs, analog outputs, counters and timers.

http://www.mathworks.com/help/toolbox/daq/bskx95j.html

Answer 4

[Randy82]

Ok, thanks for your help so far. I looked up what devices are supported now...

So I could use NI 9263 device. Thats an analog output module. I looked up in the help directory how it could work with the session based interface.

But how can I get a step function out of it? I need to set a signal of 4,5 volts for about 1 second out of it.

Answer 5

[Randy82]

Hey Chirag, thank you very much. I will try this.

Do you think on the other side there is a possibility to listen in an GUI with matlab to my National Instruments NI 9201 analag input and do some action in the GUI when the input is more than 4 Volts? I dont know if it would possible to listen all the time for an inputsignal.