Round Real to 2 decimal places

[alenck 0]

How can i round real number to 2 decimal places in sysmac?

 

[BobLfoot 272]

Can you Multiply the real by 100 and place it in an integer and then divide that integer by 100 back into a real?

[alenck 0]

i did this:

SCALE_REAL_TEMP:=SCALE_REAL_TEMP*100;
SCALE_REAL_TEMP_INT:=Round(SCALE_REAL_TEMP);
SCARE_REAL_TEMP_FINAL:=DINT_TO_REAL(SCALE_REAL_TEMP_INT);

Scale_Analogue_2dec :=SCARE_REAL_TEMP_FINAL/100;

But still i get more then 2 decimal places, ex. 10.0099999

[Crossbow 277]

Real numbers have as many decimal places as they need.  I do not know of a way to truncate that to 2 digits.  You can typically do that on any operator interface terminal for display.

[pturmel 105]

Floating point doesn't support fractions like humans do.  If the fractional part's denominator isn't entirely divisible by two, you get a repeating "binarial" just like you get repeating decimals in base ten for denominators not divisible by ten.

[BE 11]

I created a function for this on my last project. It basically uses the method that @BobLfoot said, and also has an input so you can set how many decimal places you want. From memory, when looking at the output variable from this function, they still showed a heap of decimal places (ie. 123.45000000), but they were only ever trailing 0's. Personally, I needed it just to round off scaled temperatures & weights (which were on analogue inputs) to make my life a bit easier on the HMI side of things. I have attached the function below in case it might be of use.

Trunc Real Decimals Function.smc2