Counting Boolean Transitions

[Dennis D.]

Can anyone give me an example of how you could count boolean transitions in Labview? I thought it would be easy but haven't fiqured a way to do it.

[tst]

You need a shift register, which holds the value of the last iteration of the loop. Then, you can compare it to the current value and see if it changed. This will only detect changes that happen less frequently than the loop's delay. To create a shift register, right click on the left or right loop border and select Create>>Shift Register.

If doesn't help, write some more details about where you're getting your boolean values from and how often do you check them.

[Bob_Y.]

In a loop, keep the state of the boolean in a shift register. Compare the present value with the stored state. If a change has been made (not equal), increment the counter (also stored on a shift register). See the attached VI

Hope that this helps,
Bob

[Dennis D.]

Thanks! I had been using a shift register, but not correctly. The example using the Select function cleared up a few things for me.

[tone5]

Many thanks Bob Y

The example you uploaded was a big help to me.