Safety network for industrial controller having reduced bandwidth requirements
AssigneeRockwell Automation Technologies, Inc.
InventorsJoseph A. Lenner, David A. Vasko, Kerry W. Vandesteeg, Kenwood H. Hall
Life of this patent
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Abstract
A highly reliable industrial control system provides for the processing of redundant control signals on as little as a single serial network without overloading the network by preprocessing input signals for coincidence and sending only the coincidence signal either periodically or on a change of state. Further compression of sent data is realized by extracting a reduced subset of transmission states from the input signals and transmitting only the transmission states.
Claims26
A high reliability industrial control system comprising:
- a controller including a first network interface to a shared serial network;
- an input module having at least two interface circuits for receiving at least two redundant input signals, the interface circuits communicating with at least one processor via an internal bus, the processor further communicating with a second network interface to the shared serial network;
- wherein the processor executes a stored program to:
- (i) receive the redundant input signals processed by the interface circuits;
- (ii) determine a coincidence of the redundant input signals within a window of a predefined time period;
- and
- (iii) only when there is coincidence within the window, transmitting via the second network interface, at least one coincidence signal indicating a coincident state of the redundant input signals to the controller.
A method of operating an industrial control system including a controller having a first network interface to a shared serial network;
- and an input module having at least two interface circuits for receiving redundant input signals, the interface circuits communicating with at least one processor via an internal bus, the processor further communicating with a second network interface to the shared serial network, the method comprising the steps of:
- wherein the processor executes a stored program to:
- (i) receive the redundant input signals at the input module;
- (ii) at the input module, determining a coincidence of the redundant input signals within a window of predefined time period;
- and
- (iii) only when there is coincidence within the window, transmitting from the input module to the controller via the second network interface, at least one coincidence signal indicating a coincident state of the redundant input signals.
An industrial control system for operation in conjunction with a safety system, the industrial control system comprising:
- a serial network;
- a controller including a first network interface coupled to the serial network;
- and
- an input module having at least two interface circuits coupled to a processing device, wherein the processing device includes a second network interface coupled to the serial network;
- wherein the processing device determines whether at least two redundant input signals have been received within a time window by way of the interface circuits and, if so, transmits a signal onto the serial network;
- and
- wherein the time window is a maximum amount of time that it would take for the redundant input signals to be provided by at least two properly-operating redundant components of the safety system in response to a state change of the safety system.
An industrial system for performing an industrial process comprising:
- a system component that performs an operation related to the industrial process;
- at least one sensor providing at least two redundant sensor signals concerning a status of the system component;
- at least two separate physical conductors;
- an input module having at least two interface circuits and a processing device having a first network interface, wherein the at least two interface circuits are coupled to the at least one sensor by way of the at least two separate physical conductors, respectively, by which the at least two interface circuits receive the at least two redundant sensor signals, respectively,
- a controller including a second network interface;
- and
- a network coupling the first and second network interfaces;
- wherein the processing device determines whether the at least two redundant sensor signals have been received at the input module and, if so, transmits a single coincidence signal onto the serial network for receipt by the controller.
Dependencies are inferred from the claim text.