Modbus Rtu Commands - Siemens SITRANS LG270 Operating Instructions Manual

Register Name Register Number
PV 2202
SV 2204
TV 2206
QV 2208
Unit Codes for Register 104, 108, 112, 116
Unit Code
32
33
40
41
42
43
44
45
46
47
48
49
111
112
113

10.4 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
Function Code
Start Address
Number of Registers
Response:
Parameter
Function Code
88
Type Note
DWord Primary Variable in Byte Order BACD (Middle Endian)
DWord Secondary Variable in Byte Order BACD (Middle En-
dian)
DWord Third Variable in Byte Order BACD (Middle Endian)
DWord Quarternary Variable in Byte Order BACD (Middle En-
dian)
Measurement Unit
Degree Celsius
Degree Fahrenheit
US Gallon
Liters
Imperial Gallons
Cubic Meters
Feet
Meters
Barrels
Inches
Centimeters
Millimeters
Cubic Yards
Cubic Feet
Cubic Inches
Length
1 Byte
2 Bytes
2 Bytes
Length
1 Byte
SITRANS LG270 - Operating Instructions
Code/Data
0x03
0x0000 to 0xFFFF
1 to 127 (0x7D)
Code/Data
0x03
PBD-51041066