Method and system for polling communication devices in an industrial network system

A host device for polling communication devices in a communication system comprising the host device and the communication devices, wherein the host device is connected to the communication devices via a clock line for transmitting a clock signal to the communication devices and via an arbitration line implemented with “OR” logic for receiving arbitration signals transmitted by the communication devices, wherein each of the communication devices is configured to pull up or down the arbitration line for sending an arbitration signal when one of the communication devices is ready to send data to the host device, wherein each of the communication devices is configured to pull down the arbitration line for sending an arbitration signal when one of the communication devices has no data to send to the host device, the host device comprising:

• one or more network interfaces to communicate with the communication devices,
• a processor coupled to the network interfaces and configured to execute one or more processes;
• and
• a memory configured to store a process executable by the processor, the process when executed operable to:
• send a clock signal on the clock line during an arbitration cycle, the communication devices sending respective arbitration signals towards the arbitration line in response to the clock signal on the clock line, during the arbitration cycle, the arbitration signals sent by the communication devices being added to each other on the arbitration line by the “OR” logic thereof to produce a final signal, the final signal having a sequence of bits, different bits in the sequence of bits corresponding to different ones of the communication devices, a “1” bit in the sequence of bits indicating that a corresponding communication device is ready to send data and a “0” bit indicating that the corresponding communication device is not ready to send data,
• receive the final signal corresponding to the addition of the arbitration signals, during the arbitration cycle, resulting from the “OR” logic applied to the arbitration signals,
• detect that the communication devices are ready to send data based on the “1” bits of the final signal,
• select, among the communication devices that were detected as ready to send data, the communication device associated with the highest priority in a priority table containing the priorities associated with the communication devices, and
• poll the selected communication device to receive data from the selected communication device during a communication cycle.