Hamilton-sundstrand-company Fuel Metering Valves XVG Manuel d'utilisateur télécharger pdf (Page 7)

7.4 Modbus Functions

The following Modbus functions are supported by the XVG/eXVG:

- Read Registers (0x03)

- Write Single Register (0x06)

- Write Multiple Registers (0x10)

- Diagnostics (0x08) Query Data sub-function (0x00)

The master can address individual slaves, or can initiate a broadcast message (using

device address 0) to all slaves. Slaves perform the actions requested by the broadcast

messages but will not return a response. Per Modbus protocol, only Write Single

7.4.1 Read Registers (0x03)

Request message:

SLAVE ADDRESS + FUNCTION CODE + STARTING ADDRESS + QUANTITY

OF REGISTERS + CRC

Request Length Valid Value

Slave Address 1 Byte 0 to 247

Function code 1 Byte

0x03

Starting Address 2 Bytes

0x0000 to 0xFFFF

Quantity of Registers 2 Bytes

1 to 125 (0x7D)

CRC 2 Bytes

0x0000 to 0xFFFF

Table 4: Modbus Function 03 – Request Message

Response message:

SLAVE ADDRESS + FUNCTION CODE + BYTES COUNT + REGISTERS

VALUES + CRC

Response Length Valid Value

Slave Address 1 Byte 0 to 247

Function code 1 Byte

0x03

Byte count 1 Byte

2xN

Registers Values 2xN Bytes

value

CRC 2 Bytes

0x0000 to 0xFFFF

*N = Quantity of Registers

Table 5: Modbus Function 03 - Response Message

1 2 3 4 5 6 7 8 9 10 11 12 ... 35 36

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Hamilton-sundstrand-company Fuel Metering Valves XVG Manuel d'utilisateur Page 7