How do I convert an integer to floating point and vice versa in a Rockwell Controller?

The database addresses of each ProSoft card consist of 16 bit integers.  Therefore when dealing with 32 bit floating point or real values, they are stored as two consecutive 16bit integers.

Converting from Integers into Floats

In all versions of RSLogix, the COP (COPy) function is used to convert between integer and floating point data the syntax is:

COP  <SOURCE> <DESTINATION> <LENGTH>

Please keep in mind that the LENgth parameter is for the destination table or array.

In this example, a float value of '12.34' will be represented as '28836 and 16709' in the ProSoft card.  You will need to create a COP statement that copies both Integer values into a single Real tag/table. 

MCM.DATA.ReadData[x] is a (16bit) Int data type.

Specifically, MCM.DATA.ReadData[0] will contain the value 28836 and MCM.DATA.ReadData[1] will contain 16709.

FloatData[0] is a Real data type.

It is the data type of the Destination of the COP statement that dictates the Length parameter.  A Length of '1' means the logic will use 2 consecutive integers starting at MCM.DATA.ReadData[0] to create 1 float.

Not all pairs of integer values will comprise a valid float, so it is possibly the resulting float value is not valid.  There may be an issue with the order in which the bytes/words were placed when converting to a float. You may need to try a different ‘Swap code’ parameter for each MCM command.  It can swap the two words, the bytes, or both.