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The protocol is selected with sections 4 and 5 of the S3 switch according to the table:




Off (0)

Off (0)

Modbus RTU

Off (0)

On (1)

Modbus ASCII

On (1)

Off (0)

BACnet master

On (1)

On (1)

BACnet slave

Protocol selection


The BACnet slave mode does not support the discover function.

Free Modbus TCP Sockets Counter


The free Modbus TCP sockets counter is implemented from the 7.0 firmware.

The counter of free Modbus TCP sockets informs the user about the number of available Modbus TCP connections for the device.

The maximum number of TCP connections is 4.

The number of free Modbus TCP sockets can be reached in two ways:

  • in the 292 Modbus register (read-only): the register shows values from 0 to 4, where 0 means no available connections, 4 means 4 available connections;
  • in the IP Configuration tab in the web server.

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