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read function in DAQ is hidden by a built in function

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I want to run read in DAQ toobox but get an error message:
Incorrect number of types of input or output for function 'read'.
When I type "help read" I get:
read - read one or more video frames
when I run "which read"
read is a built in method
So the daq read function is shadowed by something else how can I get rid of the shadowing so that I can use read from DAQ toolbox?
  6 Comments
Lars Eriksson
Lars Eriksson on 1 Feb 2024
Thanks for the feedback and input.
The s=daq.createsession() works fine for me (when I wrote my last comment I wasn't sitting at the measurement computer with the daq card to see if I wrote 'NI'/'ni'/"ni", it was done in a separate script, the rest was copied verbatim from the script I used). Whatever string I used, I got the session working and could control the device, and I could do most things with outputs/inputs. I could get the work done and acquired a sample of the right size by setting up an output and queueing a dummy output with the right length using queueoutput(s,dummy) and then running it with out=daq.startforeground(s). However, this is like going over the river for water when it is only the result of the vanilla read-function that I needed for my usage.
The read statement proposed doesn't have any way to control the length of acquisition. I need to have the right sampling time and length to match the data. I want to use this from the help.
scanData = read(d,span)
Unfortunately I'm out travelling so I can't test if this particular call to the read function gives the same error message or if it get passed to the right read function, I will do it as soon as I'm back.
There are plenty of variants of the "read" function. Writing "help read" gives "read - Read one or more video frames" on my machines. Clicking on "other uses of read" gives a batch of functions that are named "read". Matlab didn't detect the one I wanted to use, I'll experiment further when I am back after my travels.
Walter Roberson
Walter Roberson on 1 Feb 2024
s = daq("ni");
potentially creates a different kind of object.
I agree that read(s) does not permit you to specify the number of scans. The point is to test whether read(s) will give the error about incorrect number of parameters.

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