Instructions

Connection of the instrument 22
Manual econ sens3 Version 3.0
5.7 Modbus RTU connection
Over the Modbus RTU RS485 protocol, the values can be retrieved according to the Modbus submenu
in Chapter 8.10.
In order to use Modbus RTU, a Modbus master is required. Up to 32 participants can be
interconnected in a segment. For more than 32 participants, repeaters (line amplifiers) must be used
to connect the individual segments. The devices are connected in a line structure as shown in Fig. 11.
Other bus topologies, such as a star topology, are not possible.
5 MODBUS RTU connection
Pin No.
Name
Function
1
Alarm
2
24V
Input for supply over 24 VDC
3
B-
Data cable B (-) MODBUS RTU
4
A+
Data cable A (+) MODBUS RTU
5
GND
Shared GND connection for A+ and B-
Figure 11: Assignment of Modbus RTU interfaces (here with econ sens3 as gateway)