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

Page 84

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84

11 Supplement

VEGAFLEX 81 • Modbus and Levelmaster protocol

41828-EN-130314

Register Name

Register Number

Type

Note

TV

2206

DWord

Third Variable in Byte Order BACD (Middle Endian)

QV

2208

DWord

Quarternary Variable in Byte Order BACD (Middle En-

dian)

Unit Codes for Register 104, 108, 112, 116

Unit Code

Measurement Unit

32

Degree Celsius

33

Degree Fahrenheit

40

US Gallon

41

Liters

42

Imperial Gallons

43

Cubic Meters

44

Feet

45

Meters

46

Barrels

47

Inches

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

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