Wireless Valve Control Loop With Non-Periodic Update Logic
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Solution Overview
Problem
Process control systems face challenges with wireless communication reliability and power consumption in industrial settings, particularly in wireless valves, where frequent control signals and synchronization issues lead to increased power usage and communication delays, affecting control loop performance.
Innovation Solution
A control technique that reduces the number of communications between a controller and a wireless valve by implementing a non-periodic communication block, which minimizes power consumption and valve movements by sending control signals only when specific criteria are met, such as time since last communication and change in target value, while maintaining robust control performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequent control signals are sent to the wireless valve, then control performance is improved, but power consumption increases
Solution Approach 1:
The patent implements non-periodic control signal transmission where signals are sent only when specific criteria are met (process variable changes exceed a threshold, or time since last signal exceeds a threshold). This replaces traditional periodic control signals with event-driven periodic action, reducing unnecessary transmissions while maintaining control effectiveness.
Solution Approach 2:
The control signal transmission frequency is made dynamic rather than fixed. The system adapts the transmission rate based on process conditions (variable stability, threshold crossings) and timing constraints, allowing frequent signals when needed and infrequent signals when the system is stable, thus optimizing the balance between control performance and power consumption.
2Stability of the object's composition
If control signals are sent periodically, then synchronization is improved, but communication delays increase
Solution Approach 1:
The patent uses non-periodic action triggered by specific events (threshold crossings, time-based conditions) rather than fixed periodic intervals. This allows the system to maintain synchronization when needed while avoiding unnecessary communication delays during stable periods, effectively reducing overall communication delay loss.
3Use of energy by moving object
If the number of controller updates is reduced, then power consumption is reduced, but control loop performance deteriorates
Solution Approach 1:
The system implements intelligent non-periodic updates based on process variable changes and time thresholds. Updates occur when the process variable changes by more than a predetermined amount or when a predetermined time period elapses, ensuring control loop performance is maintained while reducing unnecessary updates that would only consume power.
Solution Approach 2:
The patent dynamically adjusts control parameters including update frequency, signal transmission timing, and threshold values based on process conditions. This allows the system to optimize the balance between power consumption and control performance by adapting parameters rather than using fixed values.
Data Source
AI summary
A control technique controls a process in a manner that reduces the number of controller changes provided to a controlled device, and so reduces the power consumption of the controlled device along with the loading of a process control communications network disposed between the controller and the controlled device. This technique is very useful in a control system having wirelessly connected field devices, such as sensors and valves which, in many cases, operate off of battery power. Moreover, the control technique is useful in implementing a control system in which control signals are subject to intermittent, non-synchronized or significantly delayed communications and/or in a control system that receives intermittent, non-synchronized or significantly delayed process variable measurements to be used as feedback signals in the performance of closed-loop control.