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4 modbus rtu commands, Fc3 read holding register, Fc4 read input register – VEGA VEGAFLEX 81 Modbus and Levelmaster protocol Coax probe User Manual

Page 77: Fc6 write single register

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77

11 Supplement

VEGAFLEX 81 • Modbus and Levelmaster protocol

42283-EN-130314

Unit Code

Measurement Unit

48

Centimeters

49

Millimeters

111

Cubic Yards

112

Cubic Feet

113

Cubic Inches

11.4 Modbus RTU commands

FC3 Read Holding Register

With this command, any number (1-127) of holding registers can be read out. The start register,

from which the readout should start, and the number of registers are transmitted.
Request:

Parameter

Length

Code/Data

Function Code

1 Byte

0x03

Start Address

2 Bytes

0x0000 to 0xFFFF

Number of Registers

2 Bytes

1 to 127 (0x7D)

Response:

Parameter

Length

Code/Data

Function Code

1 Byte

0x03

Start Address

2 Bytes

2*N

Register Value

N*2 Bytes

Data

FC4 Read Input Register

With this command, any number (1-127) of input registers can be read out. The start register, from

which the readout should start, and the number of registers are transmitted.
Request:

Parameter

Length

Code/Data

Function Code

1 Byte

0x04

Start Address

2 Bytes

0x0000 to 0xFFFF

Number of Registers

N*2 Bytes

1 to 127 (0x7D)

Response:

Parameter

Length

Code/Data

Function Code

1 Byte

0x04

Start Address

2 Bytes

2*N

Register Value

N*2 Bytes

Data

FC6 Write Single Register

With this function code an individual holding register can be written.