Transmitting data packets in an industrial wireless network

A wireless communication device for an industrial wireless network of a process control system where an industrial process is controlled by a process control device based on process control data concerning process control properties and collected using the industrial wireless network, the wireless communication device providing a node in the industrial wireless network and comprising:

• a transmission buffer with a transmission queue;
• a wireless transmitter transmitting data packets in the transmission queue;
• and
• a packet investigating unit configured to:
• investigate when there is more than one data packet with process control data representing the same process control property from the same data originating device destined for the process control device in the transmission queue, said data originating device being an interface to the process being controlled and configured to sense more than one process control property;
• and
• when there is more than one data packet with process control data representing the same process control property from the same data originating device destined for the process control device in the transmission queue, then further configured to:
• compare time stamps of the data packets, where a time stamp reflects the time of generation of a corresponding data packet;
• keep the newest data packet;
• and
• discard older data packets, so that only the most recent data packets from a data originating device are sent to the process control device from said node,
• wherein the packet investigating unit is further configured to compare the age of the packets in the transmission queue with an age threshold, which age threshold has a value related to a control cycle of the process control device, and discard data packets older than the age threshold.

A computer program product for a wireless communication device of a process control system where an industrial process is controlled by a process control device based on process control data concerning process control properties and collected using the industrial wireless network, the wireless communication device providing a node in an industrial wireless network, the computer program product comprising a non-transitory data carrier with computer program code which when run in the wireless communication device, causes the wireless communication device to:

• investigate when there is more than one data packet with process control data representing the same process control property from the same data originating device destined for the process control device in a transmission queue, said data originating device being an interface to the process being controlled and configured to sense more than one process control property;
• compare the age of the packets in the transmission queue with an age threshold, which age threshold has a value related to a control cycle of the process control device;
• discard data packets older than the age threshold;
• and
• when there is more than one data packet with process control data representing the same process control property from the same data originating device destined for the process control device in the transmission queue, then further:
• compare time stamps of the data packets, where a time stamp reflects the time of generation of a corresponding data packet;
• keep the newest data packet;
• and
• discard older data packets, so that only the most recent data packets from a data originating device are sent to the process control device from said node.