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#26 Endian formats

1.0
closed
nobody
None
2024-12-10
2022-12-05
Chuck
No

Hi Doug, what is the endian of the formats? Specifically float32? Is there a way to change it in the program?
Thanks in advance for your reply.

Discussion

  • Doug Lyons

    Doug Lyons - 2023-02-10

    I suggest that you try using the F1 key and looking at the HTML help file. To answer your question, on the "Registers" display near the top right there is a "Clone" checkbox that reverses the byte order for floats and doubles. Thanks.

     
  • Pavel Kostromitinov

    Why is it named 'Clone'?...

     
    • Doug Lyons

      Doug Lyons - 2023-04-03

      There are some manufacturers of PLC's that say they support the Modbus
      protocol that use the swapped word arrangement for floats internally.

      There is no defined standard within the Modbus documents about how a 32-bit
      IEEE-754 floating point number is stored in a Modbus PLC.

      So there is no consistency among manufacturers, other than that most that
      deviate from what Modbus does, do word swaps.

      This is what the "Clone" represents. The "Clone" selection means that this
      handles the 32-bit floats like "Clone" PLC vendors would.

      The format for 32-bit floating point that I used matches that used in an actual Modicon A984-131 processor as shown by its programming software, so this is what I call technically correct. I happen to own one of these processors and its programming software.

       

      Last edit: Doug Lyons 2024-12-10
  • Doug Lyons

    Doug Lyons - 2024-12-10
    • status: open --> closed
     
  • Doug Lyons

    Doug Lyons - 2024-12-10

    I am closing this "Bug" because it was more a "Question" that hopefully has been answered now. Please create another "Bug" report if there is anything remaining to be answered in your opinion. Thanks. Doug Lyons

     

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