State machine function block with user-definable actions on a transition between states
First Claim
1. A method of operating a state machine function block (SMFB) associated with a process plant, the SMFB executed by a controller and implementing a state machine having a transition table and a current state, the method comprising:
- receiving, by the controller from a first function block associated with the process plant, an input for the state machine, the input indicative of a condition within the process plant;
identifying, by the controller from the transition table based on the current state and the input, a next state, a transition-out action associated with the current state, and a transition-in action associated with the next state, wherein the transition-in action and the transition-out action are identified from transition action data that is associated with an input/state pair of the transition table, wherein the input/state pair (i) is displayed, by a display device, with the transition action data in a graphical user interface, and (ii) corresponds to the input for the state machine and the current state;
retrieving, from a database, a first set of executable logic associated with the transition-out action;
executing, by the controller, the first set of executable logic to cause at least one of a first field device of the process plant and a workstation of the process plant to perform a first function associated with the transition-out action;
after executing the first set of executable logic;
retrieving, from the database, a second set of executable logic associated with the transition-in action, andexecuting, by the controller, the second set of executable logic to cause performance of a second function associated with the transition-in action;
after executing the second set of executable logic, setting, by the controller, the current state of the state machine to the next state; and
upon setting the current state of the state machine, providing, by the controller, a function block output to a second function block for use in controlling a second field device of the process plant, wherein the function block output is based on the current state of the state machine.
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Abstract
A control system, a safety system, etc., within a process plant may each use one or more state machine function blocks that can be easily integrated into a function block diagram programming environment. Such a state machine function block may include one or more inputs, which may cause a state machine implemented by the state machine function block to identify a next state as well as one or more transition actions to perform in accordance with transitioning from a current state to the next state. Configuration data associated with the transition actions may be retrieved from a database based on the current and next states of the state machine and at least one of the inputs. The state machine function block may also include one or more outputs that are generated based on the state transition.
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Citations
6 Claims
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1. A method of operating a state machine function block (SMFB) associated with a process plant, the SMFB executed by a controller and implementing a state machine having a transition table and a current state, the method comprising:
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receiving, by the controller from a first function block associated with the process plant, an input for the state machine, the input indicative of a condition within the process plant; identifying, by the controller from the transition table based on the current state and the input, a next state, a transition-out action associated with the current state, and a transition-in action associated with the next state, wherein the transition-in action and the transition-out action are identified from transition action data that is associated with an input/state pair of the transition table, wherein the input/state pair (i) is displayed, by a display device, with the transition action data in a graphical user interface, and (ii) corresponds to the input for the state machine and the current state; retrieving, from a database, a first set of executable logic associated with the transition-out action; executing, by the controller, the first set of executable logic to cause at least one of a first field device of the process plant and a workstation of the process plant to perform a first function associated with the transition-out action; after executing the first set of executable logic; retrieving, from the database, a second set of executable logic associated with the transition-in action, and executing, by the controller, the second set of executable logic to cause performance of a second function associated with the transition-in action; after executing the second set of executable logic, setting, by the controller, the current state of the state machine to the next state; and upon setting the current state of the state machine, providing, by the controller, a function block output to a second function block for use in controlling a second field device of the process plant, wherein the function block output is based on the current state of the state machine. - View Dependent Claims (2, 3)
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4. A state machine controller unit for use in a process control system of a process plant, the state machine controller unit communicatively coupled to a set of field devices and implementing a state machine having a transition table and a current state, and the state machine controller unit comprising:
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a controller executing a state machine function block (SMFB) configured to; receive, from a first function block associated with the process plant, an input indicative of a condition within the process plant, identify, from the transition table based on the current state and the input, a next state, a transition-out action associated with the current state, and a transition-in action associated with the next state, wherein the transition-in action and the transition-out action are identified from transition action data that is associated with an input/state pair of the transition table, wherein the input/state pair (i) is displayed, by a display device, with the transition action data in a graphical user interface, and (ii) corresponds to the input indicative of the condition and the current state, retrieve, from a database, a first set of executable logic associated with the transition-out action, execute the first set of executable logic to cause at least one of a first field device of the process plant and a workstation of the process plant to perform a first function associated with the transition-out action, after executing the first set of executable logic; retrieve, from the database, a second set of executable logic associated with the transition-in action, and execute the second set of executable logic to cause performance of a second function associated with the transition-in action, after executing the second set of executable logic, set the current state of the state machine to the next state, and upon setting the current state of the state machine, provide an output to a second function block for use in controlling a second field device of the process plant, wherein the output is based on the current state of the state machine. - View Dependent Claims (5, 6)
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Specification