GN-9289 User Manual
Page 43 of (70)
G-series GN-9289 Modbus TCP_UDP Rev. 1.01.docx
8.2.10 23 (0x17) Read/Write Multiple Registers
This function code performs a combination of one read operation and one write operation in a single
MODBUS transaction. The write operation is performed before the read. The request specifies the starting
address and number of holding registers to be read as well as the starting address, number of holding
registers, and the data to be written. The byte count specifies the number of bytes to follow in the write data
field.
The normal response contains the data from the group of registers that were read. The byte count field
specifies the quantity of bytes to follow in the read data field.
Request
Write Starting Address Hi
Write Starting Address Lo
Response
In case of address 0x0800, 0x0801 output register value: 0x0000, 0x0000 changes to 0x1122, 0x3344.
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