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Jose
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How to adress channels independently in data acquisition toolbox session based interface

Asked by Jose
on 24 Apr 2013
Hi,
I'm using data acquisition toolbox with the session based interface.
Is it possible, when using inpuntsinglescan and outputsinglescan, to adress lines independently? I'm scanning several sensors at the same time, and I want to perform a given action when a specific sensor displays a value independently of the other sensors values. When I use inputsinglescan I always get the values of all the channels I initialized, so for what I want to do I would have to define a if condition with the desired value in the channel i'm interested combined with all the other possibilities of values for the other channels.
Is there a better way to implement this?
Thank you in advance.

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1 Answer

Answer by Wael Hemdan on 26 Apr 2013
 Accepted Answer

Hi,
To access data on a per channel basis you need to index into the data array. For example, to look at the second channel's data you would do the following:
s = daq.createSession('ni')
s.addDigitalChannel('dev2', 'port0/line0:3', 'InputOnly')
s.addDigitalChannel('dev2', 'port0/line4:7', 'OutputOnly')
myOutputData = [0 0 0 0];
myInputData = s.inputSingleScan;
if myInputData(2) == 1
myOutputData = [1 1 1 1];
end
s.outputSingleScan(myOutputData);
Similarly, if you want to change only one output line based on the result from an input line, you can do the following:
if myInputData(1) == 1
myOutputData(3) = 0;
end
s.outputSingleScan(myOutputData)
- Wael Hemdan

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