State machine function block with user-definable actions on a transition between states

• US 10,274,926 B2
• Filed: 06/16/2015
• Issued: 04/30/2019
• Est. Priority Date: 07/09/2013
• Status: Active Grant

• Current Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Original Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Inventors: Law, Gary K., Sherriff, Godfrey R.
• Primary Examiner(s): Theriault, Steven B
• Application Number:
  US14/740,489
• Publication Number:
  US 20150277425A1
• Time in Patent Office: 1,414 Days
• CPC Class Codes: G05B 19/0426 Programming the control sequence
• CPC Class Codes: G05B 19/402 characterised by control arrangements for positioning, e.g. centring a tool relative to a hole in the workpiece, additional detection means to correct position G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/23289 State logic control, finite state, tasks, machine, fsm
• CPC Class Codes: G05B 2219/40585 Chemical, biological sensors
• CPC Class Codes: G05B 9/02 electric
• CPC Class Codes: G06F 3/01 Input arrangements or combined input and output arrangements for interaction between user and computer G06F3/16 takes precedence
• CPC Class Codes: G06F 3/033 Pointing devices displaced or positioned by the user , e.g. mice, trackballs, pens or joysticks; Accessories therefor digitisers characterised by the transducing means G06F3/041
• CPC Class Codes: G06F 3/048 Interaction techniques based on graphical user interfaces [GUI]
• CPC Class Codes: G06F 3/0484 for the control of specific functions or operations, e.g. selecting or manipulating an object, an image or a displayed text element, setting a parameter value or selecting a range

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.

Claims

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, 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.

2. The method of claim 1, further comprising:

responsive to setting the current state to the next state, setting at least one output associated with the current state.

3. The method of claim 2, wherein setting the at least one output comprises setting at least one of a state indication output and a transition output.

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:

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.

5. The state machine controller unit of claim 4, wherein the state machine function block (SMFB) is further configured to set at least one output associated with the current state responsive to setting the current state to the next state.

6. The state machine controller unit of claim 5, wherein the state machine function block (SMFB) sets the at least one output by setting at least one of a state indication output and a transition output.