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In TCP mode, an additional "Connected" connection point is available and can be used in the model to indicate if the Modbus slave is connected to a Modbus master or not. It represents the number of Modbus masters currently connected to the Modbus slave. This value will be the same for all slaves sharing an IP address and TCP port combination.
In RTU mode, an additional "Bus Activity" connection point is available and can be used in the model to indicate if the Modbus slave is receiving requests from a Modbus master.