4. Modbus, send REAL data

Modbus, send REAL data

  • G

    Hi,
    I have some real values to send via modbus from Mervis.
    Since REAL take 4 bytes, REAL should take two registers.
    How can I combine the two registers values to make one real value in C program ?

    regards.

    0
  • G

    I find it!

    Modbus data order: 1234.
    Example:
    In C program header:

    typedef unsigned long DWORD;
typedef unsigned short WORD;
union u_DWORD_TO_FLOAT{
    DWORD i;
    float f;
};

    and in the code:

    union u_DWORD_TO_FLOAT AI01;
...
AI01.i = (mb_mapping->tab_registers[20] << 16) + mb_mapping->tab_registers[21];
float value = AI01.f;

    Hope this help someone !

    0