Valve positioner and diagnostic method

A valve assembly comprising a control valve, a pneumatic valve actuator, a pressure sensor adapted to measure a pneumatic actuator pressure, a position sensor adapted to measure a valve position of the control valve, and a valve positioner, wherein the valve positioner further comprises a microprocessor system configured to store and run an embedded valve control and diagnostics software including

• an embedded valve controller configured to receive a setpoint position and at least the measured valve position and to control the valve position of the control valve, utilizing the pneumatic valve actuator,
• an embedded tracking digital twin of at least one physical part of the valve assembly, wherein the embedded tracking digital twin comprises a plurality of simulation model parameters, the plurality of simulation model parameters including at least one fault-related simulation model parameter that relates to a specific physical fault in the at least one physical part of the valve assembly,
• wherein the embedded tracking digital twin is configured to receive a control signal representing a real control of the at least part of the physical valve assembly by the embedded valve controller and to provide at least one simulated measurement result representing a simulated result of a control action in real-time during operation of the valve assembly,
• wherein the embedded tracking digital twin is configured to track an error between the at least one simulated measurement result and at least one corresponding real physical measurement result, and to adjust a value of the at least one fault-related simulation model parameter of the embedded tracking digital twin in a sense that the error is decreased, in real-time during operation of the valve assembly, and
• wherein the specific physical fault in the at least one physical part of the valve assembly is detectable and identifiable based on the adjusted value of the at least one simulation model parameter.

A diagnostic method in a valve positioner of a valve assembly, comprising

• measuring a pneumatic actuator pressure of a pneumatic valve actuator of the valve assembly,
• measuring a valve position of a control valve of the valve assembly,
• running an embedded valve controller in real-time in a microprocessor system of the valve positioner
• controlling, by the embedded valve controller, the pneumatic actuator pressure of the pneumatic valve actuator and thereby the valve position of the control valve based on a setpoint position and the measured valve position in real-time during operation of the valve assembly,
• running an embedded tracking digital twin of at least one physical part of the valve assembly in the microprocessor system of the valve positioner, wherein the embedded tracking digital twin comprises a plurality of simulation model parameters, the plurality of simulation model parameters including at least one fault-related simulation model parameter that relates to a specific physical fault in the at least one physical part of the valve assembly,
• receiving, by the embedded tracking digital twin, a control signal representing a real control of the at least part of the physical valve assembly from the embedded valve controller and to provide at least one simulated measurement result representing a simulated result of a control in real-time during operation of the valve assembly,
• generating, by the embedded tracking digital twin, at least one simulated measurement result representing a simulated result of a control action in real-time during operation of the valve assembly,
• tracking, by the embedded tracking digital twin, an error between the at least one simulated measurement result and at least one corresponding real physical measurement result in real-time during operation of the valve assembly, and
• adjusting, by the embedded tracking digital twin, a value of the at least one fault-related simulation model parameter of the embedded tracking digital twin in a sense that the error is decreased, in real-time during operation of the valve assembly, wherein the specific physical fault in the at least one physical part of the valve assembly is identifiable based on the adjusted value of the at least one simulation model parameter.