Controlling digital I/O's on USB-6009-OEM

[ojohnsen79]

Hello.

I'm using a USB-6009-OEM in a project I'm working on.

And I have a quick question in regards to controlling the I/O's on the DAQ.

Currently, to be able to control each I/O individually, I'm opening a task for each and every I/O at the start of the program, and tucking them away in a cluster for later use.  But my Open Task VI is starting to grow considerably in size.  So I'm curious to know if this really is the best way to do this.  Is opening a task for every I/O the only way to do it, if you want to be able to write to a pin without messing with the values on the other pins on the port?

BR,

Øystein Johnsen.

[GerdW]

Hi Øystein,

you can combine all pins of a port in one DAQmx task.

When you output a new value for a single pin you need to keep track of the other pin's state and combine them to one value by (boolean) ORing them…

[ojohnsen79]

Hi GerdW.

I'm not exactly sure what you mean by combining the other pins' values by ORing them, and what this would accomplish.

Do you mean reading out the port values first, then setting the relevant pin value to whatever state, and then writing the port values again?

BR,

Øystein.

[GerdW · Accepted solution]

Hi Øystein,

no, you don't need to read out any port values.

You need to keep track of them in your VI by storing the previous values in a shift register!

[ojohnsen79]

Hi.

Yes, that would work, I guess.  I'll keep that in mind if the amount of tasks grows out of hand. 🙂

Thanks for the idea!

BR,

Øystein.