초록 ▼

An auto-tuner is adapted to be used in a distributed process control network having a communications network that communicatively couples a process controller, which executes a process control routine, and one or more process devices used in a process control loop. The auto-tuner includes a first tu

An auto-tuner is adapted to be used in a distributed process control network having a communications network that communicatively couples a process controller, which executes a process control routine, and one or more process devices used in a process control loop. The auto-tuner includes a first tuning element configured to cause a control entity to force the process loop to undergo an auto-tuning procedure and a tuning data stack operating within one of the process devices to receive and store a tuning signal associated with the control entity along with a time stamp indicating the time the tuning signal was acted on by the device. A measurement data stack is disposed in the same or a different process device and operates to receive and store a response or measurement signal generated by the process device along with a time stamp indicating when the response signal was generated or detected. A second tuning element which may be, for example, in a controller or a workstation, periodically receives data from the tuning data stack and the measurement data stack and determines a tuning parameter to be used in tuning the process loop.

대표청구항 ▼

What is claimed is: 1. An auto-tuner for use in a distributed process control network to tune a process control loop having a control entity that controls a first field device within a process and a measurement entity disposed in a field device that measures a process variable associated with the p

What is claimed is: 1. An auto-tuner for use in a distributed process control network to tune a process control loop having a control entity that controls a first field device within a process and a measurement entity disposed in a field device that measures a process variable associated with the process, the auto-tuner comprising: a first tuning element configured to generate a tuning control signal for use by the control entity within the process control loop during a tuning procedure; a first data collection entity disposed within the first field device that collects and stores a plurality control data signals associated with the control entity during the tuning procedure and a time indication associated with one or more of the control data signals; a second data collection entity disposed within the same field device as the measurement entity that collects and stores a plurality of measurement data signals associated with the measurement entity during the tuning procedure and a time indication associated with one or more of the measurement data signals; and a second tuning element configured to receive the plurality of control data signals and the plurality of measurement data signals and to determine a tuning parameter for use in tuning the control entity from the plurality of control data signals and the plurality of measurement data signals. 2. The auto-tuner of claim 1, wherein the first and second data collection entities are disposed in the same field device. 3. The auto-tuner of claim 1, wherein the first and second data collection entities are disposed in different field devices. 4. The auto-tuner of claim 1, wherein the first and second data collection entities are trend objects in a fieldbus protocol. 5. The auto-tuner of claim 1, wherein the first tuning element is configured to generate a tuning control signal that causes the control entity to generate a step input or sinusoidal control signal. 6. The auto-tuner of claim 1, wherein the first tuning element is located in the same device as the control entity. 7. The auto-tuner of claim 6, wherein the first tuning element and the control entity are located in a controller. 8. The auto tuner of claim 1, wherein the first tuning element is located in a different device than the control entity and wherein the control entity is located in a field device associated with the process. 9. The auto-tuner of claim 1, wherein the first tuning element generates the tuning control signal for delivery to the control entity and the first data collection entity collects and stores the tuning control signal as received by the control entity. 10. The auto-tuner of claim 1, wherein the first tuning element generates the tuning control signal for delivery to the control entity that causes the control entity to generate an output control signal and wherein the first data collection entity collects and stores the output control signal. 11. The auto-tuner of claim 10, wherein the control entity includes a proportional, integral, derivative control routine. 12. The auto-tuner of claim 10, wherein the control entity includes a proportional, integral control routine. 13. The auto-tuner of claim 10, wherein the control entity is includes a fuzzy logic control routine. 14. The auto-tuner of claim 1, wherein the first data collection entity sends a multiplicity of control data signals to the second tuning element at the same time. 15. The auto-tuner of claim 1, wherein the second tuning element determines an ultimate gain as a process characteristic and uses the ultimate gain to determine the tuning parameter. 16. The auto-tuner of claim 1, wherein the second tuning element determines a time constant as a process characteristic and uses the time constant to determine the tuning parameter. 17. The auto-tuner of claim 1, wherein the first and the second data collection entities communicate with the second tuning element asynchronously via a bus. 18. The auto-tuner of claim 17, wherein the bus is a fieldbus protocol bus. 19. A process control system for use in controlling a process, comprising: a controller device connected within the process to perform control activities within the process; a plurality of field devices communicatively coupled to the controller, each of the plurality of field devices including a processor and a memory; a control loop including a control entity and a measurement element, wherein the measurement element is stored in the memory and is adapted to be executed on the processor of a first one of the field devices; and an auto-tuner adapted to tune the control loop, the auto tuner including; a first tuning element configured to generate a tuning control signal to cause the control entity to drive the control loop to undergo a tuning procedure; a first data collection entity adapted to collect and store a plurality of control data signals associated with the control entity during the tuning procedure and a time indication associated with one or more of the control data signals; a second data collection entity disposed within the first one of the field devices and adapted to collect and store a plurality of measurement data signals associated with the measurement element during the tuning procedure and a time indication associated with one or more of the measurement data signals; and a second tuning element configured to receive the plurality of control data signals and the plurality of measurement data signals and to determine a tuning parameter for use in tuning the process control loop from the plurality of control data signals and the plurality of measurement data signals wherein at least one of the first and second data collection entities is disposed within a different device than the first and second tuning elements. 20. The process control system of claim 19, wherein the first and second data collection entities are disposed in the same field device. 21. The process control system of clam 19, wherein the first and second data collection entities are disposed in different field devices. 22. The process control system of claim 19, wherein the first and second data collection entities are trend objects in a fieldbus protocol. 23. The process control system of claim 19, wherein the first tuning element is located in the same device as the control entity. 24. The process control system of claim 23, wherein the first tuning element and the control entity are located in the controller. 25. The process control system of claim 19, wherein the first tuning element is located in a different device than the control entity and wherein the control entity is located in one of the plurality of field devices. 26. The process control system of claim 19, wherein the first tuning element generates the tuning control signal for the control entity and the first data collection entity collects and stores the tuning control signal as received by the control entity. 27. The process control system of claim 19, wherein the first tuning element generates the tuning control signal that causes the control entity to generate an output control signal and wherein the first data collection entity collects and stores the output control signal. 28. The process control system of claim 19, wherein the first data collection entity sends a multiplicity of the control data signals to the second tuning entity as a single communication packet using asynchronous communications. 29. The process control system of claim 19, wherein the first and the second data collection entities communicate with the second tuning element asynchronously via a bus. 30. The process control system of claim 29, wherein the bus is a fieldbus protocol bus. 31. A method for use in a distributed process control network to tune a process control loop having a control entity that controls at least one field device within the process and a measurement entity that measures a process variable within the process, the method comprising: forcing the control entity to control the at least one field device to implement a tuning procedure; collecting control data signals associated with the control entity during the tuning procedure within the at least one field device and storing the collected control data signals in a first data stack located in the at least one field device and storing a time indication associated with one or more of the control data signals in the first data stack; collecting measurement data signals associated with the measurement entity during the tuning procedure in a field device in which the measurement entity is located and storing the measurement data signals in a second data stack located in the field device in which the measurement entity is located and storing a time indication associated with one or more of the measurement data signals; sending the control data signals within the first data stack and the measurement data signals within the second data stack to a second tuning element; using the plurality of control data signals and the plurality of measurement data signals to determine a process characteristic for use in tuning the process control loop; using the process characteristic to generate one or more tuning parameters and sending the tuning parameters to the control entity. 32. The method of claim 31, wherein collecting the control data signals includes using a first trend object in a fieldbus protocol to store the control data signals and wherein collecting the measurement data signals includes using a second trend object in a fieldbus protocol to store the measurement data signals. 33. The method of claim 31, wherein forcing the control entity to control the at least one field device to implement a tuning procedure includes forcing the control entity to create a step input or sinusoidal control signal. 34. The method of claim 31, wherein forcing the control entity to control the at least one field device to implement a tuning procedure includes sending a tuning control signal to the control entity in the at least one field device and wherein collecting the control data signals includes collecting the tuning signal as received by the control entity. 35. The method of claim 31, wherein forcing the control entity to control the at least one field device to implement a tuning procedure includes sending a tuning control signal to the control entity to cause the control entity to produce an output control signal and wherein collecting the control data signals includes collecting the output control signal as generated by the control entity. 36. The method of claim 31, wherein forcing the control entity to control the at least one field device to implement a tuning procedure includes sending a tuning control signal to the control entity to cause the control entity to produce an output control signal which is delivered to a device control entity in at least one field device and wherein collecting the control data signals includes collecting the output control signal as received by the device control entity in the at least one field device. 37. The method of claim 31, wherein sending the control data signals within the first data stack and the measurement data signals within the second data stack to the second tuning element includes sending two or more of the control data signals in a first data message to the second tuning entity and sending two or more of the measurement data signals in a second data message to the second tuning entity. 38. The method of claim 37, wherein the step of sending two or more of the control data signals in the first data message includes sending the first data message asynchronously to the second tuning element and wherein sending two or more of the measurement data signals in the second data message includes sending the second data message asynchronously to the second tuning element. 39. The method of claim 31, wherein using the plurality of control data signals and the plurality of measurement data signals to determine a process characteristic includes determining an ultimate gain as the process characteristic. 40. The method of claim 31, wherein using the plurality of control data signals and the plurality of measurement data signals to determine a process characteristic includes determining a time constant as the process characteristic. 41. The method of claim 31, wherein sending the tuning parameters to the control entity includes sending the tuning parameters to the control entity asynchronously. 42. The method of claim 41, wherein sending the tuning parameters to the control entity includes sending the tuning parameters to the control entity asynchronously via a fieldbus protocol communication bus.