STATE MACHINE FUNCTION BLOCK WITH USER-DEFINABLE ACTIONS ON A TRANSITION BETWEEN STATES

• US 20150277425A1
• Filed: 06/16/2015
• Published: 10/01/2015
• Est. Priority Date: 07/09/2013
• Status: Active Application

• 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.
• Granted Patent: US 10,274,926 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 first function block associated with a process plant, the first function block implementing a state machine having a transition table and a current state, the method comprising:

receiving an input for the state machine, the input indicative of a condition within the process plant;

examining the transition table to identify, based on the current state and the input, a next state and at least one transition action;

initiating, by the first function block, the at least one transition action;

setting the current state of the state machine to the next state; and

providing a function block output to a second function block for use in controlling a field device, wherein the function block output is based on the current state of the state machine.

2. The method of claim 1, wherein the at least one transition action specifies a transition-out action and a transition-in action, and wherein initiating the at least one transition action comprises:

initiating, by the first function block, the transition-out action; and

initiating, by the first function block, the transition-in action.

3. The method of claim 2, wherein the first function block initiates the transition-out action prior to initiating the transition-in action.

4. The method of claim 2, wherein the first function block initiates the transition-in action prior to setting the current state of the state machine to the next state.

5. The method of claim 2, wherein the first function block initiates the transition-out action prior to setting the current state of the state machine to the next state.

6. The method of claim 1, wherein initiating the at least one transition action comprises providing an additional function block output to a third function block, the additional function block output indicating the at least one transition action.

7. The method of claim 1, wherein initiating the at least one transition action comprises:

retrieving at least one transition configuration item associated with the at least one transition action from a database; and

executing the at least one transition configuration item.

8. 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.

9. The method of claim 8, wherein setting the at least one output comprises setting at least one of a state indication output and a transition output.

10. A state machine controller unit for use in a process system, the state machine controller unit communicatively coupled to a field device and implementing a state machine having a transition table and a current state, and the state machine controller unit comprising:

an input module to receive an input indicative of a condition within the process system; and

an execution module configured to;

examine the transition table to identify, based on the current state and the input, a next state and at least one transition action,

initiate the at least one transition action,

set the current state of the state machine to the next state, and

provide an output for use in controlling the field device, wherein the output is based on the current state of the state machine.

11. The state machine controller unit of claim 10, wherein the at least one transition action specifies a transition-out action and a transition-in action, and wherein the execution module initiates the at least one transition action by initiating the transition-out action and initiating the transition-in action.

12. The state machine controller unit of claim 11, wherein the execution module initiates the transition-out action prior to initiating the transition-in action.

13. The state machine controller unit of claim 11, wherein the execution module initiates the transition-in action prior to setting the current state of the state machine to the next state.

14. The state machine controller unit of claim 11, wherein the execution module initiates the transition-out action prior to setting the current state of the state machine to the next state.

15. The state machine controller unit of claim 10, wherein the execution module initiates the at least one transition action by providing an additional output to an additional module, the additional output indicating the at least one transition action.

16. The state machine controller unit of claim 10, wherein the execution module initiates the at least one transition action by:

retrieving at least one transition configuration item associated with the at least one transition action from a database, and executing the at least one transition configuration item.

17. The state machine controller unit of claim 10, wherein the execution module is further configured to set at least one output associated with the current state responsive to setting the current state to the next state.

18. The state machine controller unit of claim 17, wherein the execution module sets the at least one output by setting at least one of a state indication output and a transition output.