RLE Technologies LD5100, Руководство пользователя

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8 Modbus Communication
8.2. Packet Communications For The LD5100
This section covers the registers, their names, and a brief description of what they refer to.
8.2.1 Function 03: Read Output Registers
To read the LD5100 parameter values, the master must send a Read Output Registers request
packet. The Read Output Registers request packet specifies a start register and the number of
registers to read. The start register is numbered from zero (40001 = zero, 40002 = one, etc).
Table 8.2 Read Output Registers Packet Structure
Read Registers Request Packet Read Registers Response Packet
Slave Address (1 byte) Slave Address (1 byte)
03 (Function code) (1 byte) 03 (Function code) (1 byte)
Start Register (2 bytes) Byte count (1 byte)
# of registers to read (2 bytes) First register (2 bytes)
Crc Checksum (2 bytes) Second register (2 bytes)
…
Crc Checksum (2 bytes)