the conversation of the data type

Hello,

this is a kind of a system properties.

When calculating with real numbers, rounding errors typically occur through the structure of real numbers (exponential view) and the high value range, so that parity (all bits are the same) hardly ever occurs. Comparing real numbers for "parity" thus does not usually produce the desired results, so other options are provided here. One of these options would be to employ an approximation. This entry presents an approximation which you can use to check real numbers for "parity".

See the possibilities of convert of data types in the TIA Portal for the S7-1200/1500 in the FAQ:

http://support.automation.siemens.com/WW/view/en/48711306

With best regards
Cicero