LREAL from four WORDs?

2022-11-18T11:57:51.294000Z

if it is about modbus you could try first the following:

1) in the settings of the channel set length of reading 4. So in the Mapping it shows like ARRAY[0..3] OF WORD
2) when map this value directly to LREAL variable.

Must be tested, but it works for me for REAL values. In the channel settings like ARRAY [0..1] OF WORD but can be directly mapped to REAL var (Codesys > 3.5.12)

LREAL from four WORDs?

2022-11-17T08:24:31.054000Z

I would create a type like this :

TYPE LREAL_WORD :
  UNION
    value : LREAL;    // Needs 8 Bytes in memory
    regs : ARRAY [0..3] OF WORD;
  END_UNION
END_TYPE

Then in your program you can declare your variables like this :

my_var : LREAL_WORD;
reg_1 : WORD;
reg_2 : WORD;
reg_3 : WORD;
reg_4 : WORD;
// ...

// Maybe you'll have to change the order here...
my_var.regs[0] := reg_1;
my_var.regs[1] := reg_2;
my_var.regs[2] := reg_3;
my_var.regs[3] := reg_4;

Then it will automatically update my_var.value to the corresponding LREAL value (Beware of the endianess of the value though).
It should work but I've never tested this with WORD, only did it with BYTE...

Hope this helps !

LREAL from four WORDs?

2022-11-17T06:53:44.804000Z

I need to take 4 registers and assemble them to a LREAL. I don't know bit order so I may been have to invert all the bits.

What's the best approach to this? Tried and don't think Example_LREAL AT %IW4 : LREAL will read in the 4 WORDs.. Do I create an array, address that memory pointer and read it in that way?

Looking for advice/example, have never manipulated LREALs before..

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LREAL from four WORDs?

LREAL from four WORDs?

LREAL from four WORDs?