Hi,

I'm trying to calculate a simple expression in my FC. Depending on the order of the multiplication I might be able to get wrong answers.

My expression is #qfAng1 := 3/2 * #PI  - #fAlpha - #fBeta but this gives the wrong answer. When changing it to #qfAng1 := #PI * 3/2 - #fAlpha - #fBeta the answer is correct. I Step7 it was possible to check the compiled code in STL to see in which order the operation was executed.

All variables are declared as temp except PI (const).

Does anyone know if the problem is due to the order of operations and also if it is possible to access the compiled code in TIA Portal?

Best regards Isak

Hi Isak,

Your problem has to do with what data type you are working in.
For example.. 3 / 2     should be   3.0 / 2.0
to ensure you are working with REAL numbers.

Sometimes you need to tell the system for example..
DINT#5

or use converting methods..
INT_TO_REAL( #myIntValue)

.. give it another try with the above in mind.
w