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US 7,930,041 B2Granted
Industrial controller with coordination of network transmissions using global clock
AssigneeRockwell Automation Technologies, Inc.
InventorsEdward C. Korsberg, David A. Vasko, Darren R. Klug, Petr Ptacek
Life of this patent
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Abstract
An industrial control system communicating among various control elements via a serial network synchronizes the scanning loops associated with collecting and forwarding data along the network so as to substantially reduce transmission delay and jitter, using synchronization information passed along the network.
Claims22
An industrial control system comprising a set of spatially separated control elements interconnected on at least one network, the control elements including at least two of:
- (i) a programmable controller having a cycle defining repeated use of data within a control program;
- (ii) a network adapter having a cycle defining repeated communication with control elements on the network;
- (iii) an I/O adapter connected to the network having a cycle defining repeated communication with I/O modules having electrical connections to sensors and actuators effecting control of a controlled process;
- and
- (iv) an I/O module communicating with a controlled process having a cycle defining repeated exchange of data with the controlled process;
- and
- the industrial control system comprising:
- (i) a global clock system providing a synchronized timebase at the control elements;
- (ii) a profiler defining a master cycle initiation time based on a cycle of a given control element from the set of spatially separated control elements with reference to the synchronized timebase and providing corresponding cycle initiation times to other control elements from the set of spatially separated control elements;
- (iii) a synchronization system receiving the cycle initiation times and synchronizing execution of cycles of the control elements based on the cycle initiation times and the synchronized timebase so that data is transmitted from the other control elements to the given control element to arrive at the given control element substantially at a start of the cycle of the given control element.
7 more elements
A control element forming part of an industrial control system comprising:
- a set of spatially separated control elements interconnected on at least one network, the control elements selected from the group consisting of:
- (i) a programmable controller having a cycle defining repeated execution of a control program;
- (ii) a network adapter having a cycle defining repeated communication with control elements on the network;
- (iii) a switch element joining two networks;
- and
- (iv) an I/O adapter connected to the network having a cycle defining repeated communication with I/O modules having electrical connections to sensors and actuators effecting control of a controlled process, the controlled process having a cycle defining repeated operation of the controlled process;
- the control element comprising:
- (i) a global clock system providing a synchronized timebase coordinated with other control elements;
- (ii) a synchronization system receiving a cycle initiation times and synchronizing execution of cycles of the control element based on the cycle initiation times and the synchronized timebase so that data transmitted from the control element and to another control element arrives at the other control element substantially at a start of the cycle of the other control element.
6 more elements
A method of operating an industrial control system comprising a set of spatially separated control elements interconnected on at least one network, the control elements including at least two of:
- (i) a programmable controller having a cycle defining repeated execution of a control program;
- (ii) a network adapter having a cycle defining repeated communication with control elements on the network;
- and
- (iii) an I/O adapter connected to the network having a cycle defining repeated communication with I/O modules having electrical connections to sensors and actuators effecting control of a controlled process, the controlled process having a cycle defining repeated operation of the controlled process;
- the method comprising the steps of:
- (i) establishing synchronized timebase at the control elements;
- (ii) determining operation of a first control element to define master cycle initiation times of the cycle of the control element with reference to the synchronized timebase;
- (iii) providing corresponding cycle initiation times to other control elements;
- and
- (iv) synchronizing execution of cycles of the control elements based on the corresponding cycle initiation times and the synchronized timebase so that data transmitted between a first and second control element arrives at the second control element substantially at a start of the cycle of the second control element indicated by the master cycle initiation times.
7 more elements
Dependencies are inferred from the claim text.