85
PBD-51041066
SITRANS LG270 - Operating Instructions
44295-EN-140321
4
1
3
3
3
2
+
+
power supply
MODBUS
D0
D1
IS GND
USB
+
+
power supply
MODBUS
D0
D1
IS GND
USB
+
+
power supply
MODBUS
D0
D1
IS GND
USB
1
3 4
5
2
off on
( )
(
)
(-)
(-)
1
3 4
5
2
off on
( )
(
)
(-)
(-)
1
3
4
5
2
off on
( )
(
)
(-)
(-)
Fig. 52: Bus architecture Modbus
1 RTU
2 Connection resistor
3 Bus participant
4 Voltage supply
Protocol description
The SITRANS LG270 is suitable for connection to the following RTUs with Modbus RTU or ASCII
protocol.
RTU
Protocol
ABB Totalflow
Modbus RTU, ASCII
Bristol ControlWaveMicro
Modbus RTU, ASCII
Fisher ROC
Modbus RTU, ASCII
ScadaPack
Modbus RTU, ASCII
Thermo Electron Autopilot
Modbus RTU, ASCII
Parameters for the bus communication
The SITRANS LG270 is preset with the default values:
Parameter
Configurable Values
Default Value
Baud Rate
1200, 2400, 4800, 9600, 19200
9600
Start Bits
1
1
Data Bits
7, 8
8
Parity
None, Odd, Even
None
Stop Bits
1, 2
1
Address range Modbus
1 … 255
246
Start bits and data bits cannot be modified.