Hey guys 

Am trying to use this formula for calculating roll diameter,  but I don't know how should i find final answer that is square of a number

R2=√((L*T) /pi)+R1²) 

R2=outside radius

R1= core radius

L=film length

T= film thickness 

pi=3.14

Hello Mohsenam,

at first welcome to the Forum.

SQRT is not part of the STEP5 commands.

You didn't write which CPU you used. There are special function blocks for certain S5 CPUs, for example for the S5-135U CPU928B.
However, these are not integrated in the CPU and had to be purchased from Siemens as an additional package.

For the 928B it was FB6 (Floating point root extractor RAD: GP FB 6).

Thanks alot

The CPU that we use is the with that u said 928B

Can u explain more that how can i use FB6?!?