Modbus Rtu communication protocol - Solutions - Huaqiang Electronic Network

SMD Aluminum Electrolytic Capacitor

Brand AVX TPSE226M035R0125 - Low Impedance Tantalum Capacitor, AVX 22

Electronic Scale Crystal Oscillator, 3.2x2.5mm, 3225, 16MHz (16.000MHz), 12PF, 10PPM, 20PPM, 30PPM

Huaqiang Square - Original Crystal Stock

1. Read the holding registers (single or multiple, in words as the smallest unit) by sending a command frame:

Frame length: 8 bytes Device address: 1~247 Function code: 3H Data address: 0~65535 Quantity: 1~65535 Check code: CRC16 Return command frame:

Frame length: 5 + N bytes Device address: 1~247 Function code: 3H Data volume: Actual data read Data: Meaning of return data: a = HoldStart, n = DataNum - 1 VWa (VBa) | VWa (VBa+1) | ... | VWa+n (VBa+n+1) | Data(1) | Data(2) | ... | Data(N) Check code: CRC16 Command is incorrect: 1) No response 2) Return error frame: Device address | Function code | Error message | CRC H | CRC L

2. Set the holding register (multiple, in words as the smallest unit) by sending a command frame:

Frame length: 9 + bytN bytes Device address: 1~247 Function code: 10H Data address: 0~65535 Quantity: 1~122 Bytes: bytN = DataNum × 2 Data: Specific byte data Check code: CRC16 Return command frame: Device address | Function code | Address H | Address L | Data amount H | Data amount L | CRC H | CRC L

Frame length: 8 bytes Device address: 1~247 Function code: 10H Data address: 0~65535 Quantity: 1~122 Check code: CRC16 Command is incorrect: 1) No response 2) Return error frame: Device address | Function code | Error message | CRC H | CRC L