Communication controller for coordinating transmission of scheduled and unscheduled messages

摘要

A device on a process control network transmits scheduled messages at periodic intervals and unscheduled messages between scheduled message transmissions. A dynamic time remaining value is produced by subtracting a current timer value from a next scheduled event time each time the timer is incremented. If the time required to transmit an unscheduled message is greater than the time remaining value, the message is not transmitted.