User manual

Toolbox 32 User Manual 1.47d www.cse-semaphore.com/mykingfisher
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165
Modbus Floating Point and Long Registers
Each float or long number is stored in two 16-bit registers. A Modbus device stores the two 16-bit registers in
reverse order to a Kingfisher RTU (Kingfisher RTUs store the lower 16 bits in the lower register number).
Before using floats or longs from a Modbus device or writing floats or longs to a Modbus device, the two 16-
bit registers used for each float or long will need to be swapped as illustrated below.
│ │
├Poll floats from Modbus device RTU100 ┼ ┤
│ │
│DoEvery10sec P2 Waiting Poll Floats │
│#YTICK.10SEC #YPST2.2 RTU 100 │
├─────┤ ├─────────────────────────────────────────────────┤/├───────(RX_MBUS)──┤
│ 41001 │
│ │
│ │
├Swap floating point register order after new data received. ┤
│ │
│RTU100 Succ SwapFloatReg │
│ #YLSUCC100 #NR100.64 │
├──[CHANGE]──────────────────────────────────────────────────────────(MCopy)───┤
│ #NR100.1 │
│ │
Figure: Example ladder logic used to poll 2 Modbus floating point numbers and then swap the 16-bit register
order (note: #NR100.64 is used for temporary storage).