Converting 32-Bit Real to 2x 16-Bit Bytes

Question

I'm trying to send a 32-Bit Real across a CAN communications (IFM) but the CAN comms only accepts a 16-Bit value.

If the value I'm trying to send goes above 255, it resets back to 0 and continues in that pattern. I therefore need to split the 32-Bit Real value in to two 16-Bit values and then reassemble on the other side of the comms.

I just can't seem to get my head around how to do it in structured text.

Any help would be appreciated

Answer 1

I know I am a little late to the party but wanted to add this as a solution.

VAR
  rRealVar  :   REAL;
  awWordArray   :   ARRAY[0..1] OF WORD;
  pTemp     :   POINTER TO REAL;
  pTemp2        :   POINTER TO REAL;
END_VAR

// Get a pointer to the REAL variable
pTemp := ADR(rRealVar);

// Get a pointer to the ARRAY base
pTemp2 := ADR(awWordArray);

// Assign the value of the REAL variable into the ARRAY base
pTemp2^ := pTemp^;

(* Index 0 := Bits 15-0
   Index 1 := Bits 31-16

This is similar to Felix Keil's answer but it makes use of 2 pointer variables and a word array to retrieve the information directly.