Manual LogoTronic Hub OTC
16
7.2.1 Connection of the RS-485 interface on the circuit board
Cable connection to RS-485:
The CON29 is marked in the controller as "RS-485 COM" and counts the pin numbers from right
(pin 1) to left (pin 4), see also Chapter 3.1 Pin assignment
Pin description from right to left:
1) RS485-A
2) RS485-B
3) 24V DC supply output (to external devices)
4) GND (Ground)
The figure below shows the connection option, e.g. using a standard USB RS-485 cable connected
to a LogoTronic controller for electronically controlled interface stations.
7.2.2 Setting the controller for the Modbus protocol
Various protocols are available on the RS-485 interface. Currently, the HFC protocol (manufacturer's
own) and the open Modbus protocol are available. The protocol used on the RS-485 can be
changed using the keys on the controller (also see Chapter 6 LogoTronic Hub OTC operation and
configuration).
Interface mode (serial/Modbus):
In the factory setting, the controller operates in serial mode; this mode can be changed to Modbus
mode with the A and B keys.
Modbus mode (client/server):
The controller can be operated in client or server mode for Modbus communication. In the factory
setting, the controller operates in server mode; this mode can also be changed using the following
key combinations.
Key combination:
To change the interface or the Modbus mode, you must activate the service mode with key "B"
and select the interface with key "A".
