MathScript

[chen56]

I want to be able to transfer the labview front panel data collected from DAQmx to MathScript. I enter the code

>DEVICE='Dev1';

>>CHANNELS=[2];

>>RATE=10000;

>>SAMPLES=1000;

>>DATA=aiwf(DEVICE,CHANNELS,RATE,SAMPLES);
>>aowf(DEVICE,CHANNELS,RATE,DATA)

However, the program does not recognize channel 2, channel 2 is channel ai2 on the device, when I enter ai2, it says that the format of channel is not correct. Also, when I click on data in the variables window and click graph first, the graph does not look like the one in LabVIew front panel. Do I need to sample it at a certain rate and number of samples? Thank you.

[stilly32]

Hi Chen56,

The CHANNELS variable should just be an array of integers (check out "help aiwf"), so ai2 would just be 2. For example:

DEVICE = 'Dev1';
CHANNELS = [0, 1];
RATE = 1000;
SAMPLES = 2000;
DATA = aiwf(DEVICE, CHANNELS, RATE, SAMPLES);

This would sample off of ai0 and ai1. As far as looking at your variables graphically, you will want to sample at the same rate and number of samples if you want it to look exactly the same. Also, you may need to plot DATA. You can do this many different ways, the simplest being something along these lines:

A = DATA(1,1:1000);

B = DATA(2,1:1000);

X = 1:1000;

plot (X, B, 'b', X, A, 'r');

There are several other ways as well.

Hope this helps, let us know if there is anything else we can help with.

Andrew S.

National Instruments