Testing of Control Strategies in a Control System Controlling a Process Control Plant

• US 20080120522A1
• Filed: 11/22/2006
• Published: 05/22/2008
• Est. Priority Date: 11/22/2006
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Gnanasekaran, Sathiskumar, Puri, Jagmeet Singh
• Granted Patent: US 7,844,350 B2
• Time in Patent Office: Days
• US Class Current: 714/37
• CPC Class Codes: G05B 2219/24038 Several test signals stored in memory and used as input signals
• CPC Class Codes: G05B 2219/33286 Test, simulation analysator
• CPC Class Codes: G05B 2219/33324 What to diagnose, whole system, test, simulate
• CPC Class Codes: G05B 23/0208 characterized by the configuration of the monitoring system
• CPC Class Codes: G05B 23/0256 injecting test signals and analyzing monitored process response, e.g. injecting the test signal while interrupting the normal operation of the monitored system; superimposing the test signal onto a control signal during normal operation of the monitored system

Abstract

Test cases to test control strategies of a control process are specified in input files. The instructions in the input files are automatically read by a block tester, which interfaces with the control system to issue the instructions. As a test designer can create the instructions in the input files a priori, the tests may be carefully designed to avoid errors, in addition to performing exhaustive tests.

Claims

1. A method of testing a control strategy in a control system, wherein said control strategy contains a functional block having a plurality of variables and an output variable, said functional block being designed to generate output values for said output variable from input values received for said variables according to a control approach, said method comprising:

receiving from a file a set of input values for a test case, wherein each of said set of input values is specified to be provided as a corresponding one of said plurality of variables;

providing to said control system said set of input values as values corresponding to said plurality of variables, wherein said control system generates an actual output value for said output variable according to said control approach by providing said input values to said functional block; and

obtaining said actual output value from said control system.

2. The method of claim 1, further comprising storing said actual output value in said file.

3. The method of claim 2, wherein said receiving receives from said file an expected output value for said output variable also in said file, said method further comprising:

comparing said expected output value with said actual output value; and

storing a result of said comparing in said file.

4. The method of claim 1, wherein said receiving receives from said file a wait value associated with said output variable, wherein said obtaining waits a time duration determined by said wait value prior to retrieving said output value for said output variable.

5. The method of claim 1, wherein said receiving receives a first variable from said file, wherein said first variable is contained in said plurality of variables is set to a CASCADE mode, wherein the input value for said first variable is received as an output value from another functional block in response to setting said first variable to said CASCADE mode, wherein said another functional block is specified by said control strategy.

6. The method of claim 1, wherein said first file contains an instruction, wherein said providing sends said instruction to said control system and receives a state of said control strategy in response, said method further comprising storing said state in a memory.

7. The method of claim 6, wherein said first file contains a restore instruction, said method further comprising retrieving said state from said memory, and loading said state to said control strategy in response to said restore instruction.

8. The method of claim 1, wherein said first file contains a first instruction and a second instruction, said method further comprising setting a second variable of a second control strategy in a database to a corresponding value in response to said first instruction, and loading said second control strategy to said control system in response to said second instruction.

9. A computer readable medium carrying one or more sequences of execution statements for causing a system to test a control strategy in a control system, wherein said control strategy contains a functional block having a plurality of variables and an output variable, said functional block being designed to generate output values for said output variable from input values received for said variables according to a control approach, wherein execution of said one or more sequences of execution statements by one or more processors contained in said system causes said one or more processors to perform the actions of:

receiving from a file a set of input values for a test case, wherein each of said set of input values is specified to be provided as a corresponding one of said plurality of variables;

providing to said control system said set of input values as values corresponding to said plurality of variables, wherein said control system generates an actual output value for said output variable according to said control approach by providing said input values to said functional block; and

obtaining said actual output value from said control system.

10. The computer readable medium of claim 9, further comprising storing said actual output value in said file.

11. The computer readable medium of claim 10, wherein said receiving receives from said file an expected output value for said output variable also in said file, further comprising one or more execution statements for:

comparing said expected output value with said actual output value; and

storing a result of said comparing in said file.

12. The computer readable medium of claim 9, wherein said receiving receives from said file a wait value associated with said output variable, wherein said obtaining waits a time duration determined by said wait value prior to retrieving said output value for said output variable.

13. The computer readable medium of claim 9, wherein said receiving receives a first variable from said file, wherein said first variable is contained in said plurality of variables is set to a CASCADE mode, wherein the input value for said first variable is received as an output value from another functional block in response to setting said first variable to said CASCADE mode, wherein said another functional block is specified by said control strategy.

14. The computer readable medium of claim 9, wherein said first file contains an instruction, wherein said providing sends said instruction to said control system and receives a state of said control strategy in response, further comprising one or more execution statements for storing said state in a memory.

15. The computer readable medium of claim 14, wherein said first file contains a restore instruction, further comprising one or more instructions for retrieving said state from said memory, and loading said state to said control strategy in response to said restore instruction.

16. The computer readable medium of claim 9, wherein said first file contains a first instruction and a second instruction, further comprising one or more execution statements for setting a second variable of a second control strategy in a database to a corresponding value in response to said first instruction, and loading said second control strategy to said control system in response to said second instruction.

17. An apparatus for testing a control strategy in a control system, wherein said control strategy contains a functional block having a plurality of variables and an output variable, said functional block being designed to generate output values for said output variable from input values received for said variables according to a control approach, said apparatus comprising:

means for receiving from a file a set of input values for a test case, wherein each of said set of input values is specified to be provided as a corresponding one of said plurality of variables;

means for providing to said control system said set of input values as values corresponding to said plurality of variables, wherein said control system generates an actual output value for said output variable according to said control approach by providing said input values to said functional block; and

means for obtaining said actual output value from said control system.

18. The apparatus of claim 17, further comprising means for storing said actual output value in said file.

19. The apparatus of claim 18, wherein said means for receiving receives from said file an expected output value for said output variable also in said file, said system further comprising:

means for comparing said expected output value with said actual output value; and

means for storing a result of said comparing in said file.

20. The apparatus of claim 17, wherein said means for receiving receives from said file a wait value associated with said output variable, wherein said means for obtaining waits a time duration determined by said wait value prior to retrieving said output value for said output variable.