Patent ID: 7339948
Filing Date: 2008-03-04
Classification: H04L

Abstract:
1. A method of providing deterministic transmission of I/O data between nodes of an industrial controller communicating on an Ethernet network having a network bandwidth, the method comprising the steps of: (a) communicating information between the nodes to establish a common schedule defining for each node an owned transmission time exclusive to each node, wherein total transmission time by the nodes during an I/O cycle is less than total I/O cycle time; and (b) operating each node to transmit during the nodes owned transmission times; wherein the common schedule is established by: (i) dividing transmission time for all nodes into I/O cycles holding multiple Ethernet data packets, each node having a packet frequency, and wherein each I/O cycle has an I/O cycle time that is defined by a cycle time of the industrial controller; (ii) determining the node with the lowest packet frequency to define a schedule length of I/O cycles; (iii) scheduling a yet unscheduled node with the highest packet frequency in each of the I/O cycles of the schedule length required to meet its schedule frequency preferring least filled I/O cycles; and (iv) repeating step (iii) until all nodes are scheduled.