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AssigneeThe Dow Chemical Company
InventorsRobert S. Glaser, Robert S. Hoy, G. Paul Fernandez, Timothy J. Grai
Estimating the term…
A process control interface system having a network of distributed triply redundant input/output field computer units. The system includes a plurality of self-contained remotely located triply redundant field computer units connected to decision making redundant process control computers through a bi-directional communication network having at least two concurrently active communication channels. Each of the field computer units include a set of at least redundant field computers for arbitrating both input and output signals. The input arbitration method enables a plurality of selectable default input conditions, such as select HIGH and select LOW, in the event that a majority agreement cannot be reached among valid input signals. The output arbitration method includes a plurality of selectable default output conditions, such as fail SAFE and fail LAST. Each of the default input and output conditions may be rapidly adjusted through software selection. The field computer units also include individual abort circuits for each output signal to be transmitted to a device which affects the operation of the physical process. These abort circuits effectively enforce the output value signals arbitrated independently through each of the three redundant field computers using a voting procedure.
A method of controlling a device with an electrical control signal provided by an actively redundant computer system having a set of at least three redundant computers, each of said redundant computers having a first respective neighboring redundant computer and a second respective neighboring redundant computer within said set, comprising the steps of:
A computer-implemented process controller for controlling a device with an electrical control signal, comprising:
Dependencies are inferred from the claim text.