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LookOut expression problems

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Hello guys,

 

I've encountered a very strange situation today.  I created an expression in a server file which then be used for another calculation.  To be sure that my expression was working fine, I dragged the expression out to a panel to see if I could get a number, and I did.  The strange thing was that expression was X out as if there was no connection, but my number was still updated.  I could see my number correctly changing up and down, but the whole thing just X out.  I've tried to reboot the server to no available.  I assume that LookOut might take correct parts and leave the wrong one out which resulted in the X.  However if something in my expression was wrong (such as mistyping), LookOut wouldn't even take it at all.  I've tried to break that long expression down to piece by piece, and every single one was working fine. What would be the problem here?

 

Frank Nguyen
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Solution
Accepted by topic author Tulong

I tried to create an expression = Pot1.value+FieldPoint1.AI000.00.

The FieldPoint module doesn't exist. So, I got alarm on the FieldPoint1 object.

I saw X on the expression, and when I control Pot1, the expression value changes.

So, it looks like the same behaviour. Take a look at the expression, does it read any data from driver object?

 

Another way is to replace every single part of the expression with a constant value one by one.

Ryan Shi
National Instruments
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You are so right about that.  There are several driver connections in the expression and I mistype only one little "s" for one of them.  I just assume that LookOut will throw a fit if the driver object is not found which is always true when I try to make a connection to a modbus driver and misspell it (of course there was only one statement in the expression).  Thanks for devoting your time helping me and everyone else.

Frank Nguyen
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