two mutual exclusive condition

[connector]

Hello:

I have two valves(or you can regard them as two controls) that can not be open at the same time. If they are open(true) at the same time, a error message will be popped up.

I programmed a very simple Subvi and the final value will be used to change the local variable of the operating valve(the control whose valve will be changed). But, when I put this Subvis into my main programm, it does not work because it will close both of the valve at the same time.

The reason I have operating valve and confilicting valves is that I have to check the other valve status whenever I open one of them.

Can anyone help me for the attached programm?

Thanks a million,

[Ben]

Hi Connector,

Speaking only for myself I have to say that I am not sure what you need. At first I thought you where looking for an exclusive OR operation, but after looking at your VI, I am confused.

If you provided a truth table most all of the "frequent Flyers" here could probably fire off an answer.

Trying to help,

Ben

[connector]

Hi, Ben:

Here are the truth table:

Operating Valve Conflicting Valve HS Final status
t t t t
t t f f
t f t t
t f f t
f t t f
f t f f
f f t f
f f f f


Thanks a lot

[Ben]

A quick Venn diagram, some boolean arithetic...

See attached,

Ben

[connector]

Hello Ben:

Thanks for your help. I figure out to use this also, but How can I pop up a message to tell the operator that this operation is not valid?

have a nice day

[Ben]

Use an AND gate to drive a case structure with you one-button dialog.

Ben

[connector]

Thanks.

I tried your program. It still does not work perfectly. If a is true, when I turn on b, I can not turn on it, that's right. But, I should not turn off a at the same time.

I change a little on your code. Can you take a look at it?

Thanks,

[Ben]

So,

If [(A&B) is false ]&[C is true] then
{
Ain = Aout
Bin = Bout
{

See attached

Ben

[connector]

I really appreicate your help. Here is the code again. Actually, the output of this Subvi will be the local variables to reset the valve status.

Thanks,