ISA 100.11a Networked Control System Based on Link Stability.

Area of Science:

• Control Engineering
• Wireless Communication Systems
• Industrial Automation

Background:

• Wireless networked control systems (WNCSs) require stability and robustness against disturbances.
• Critical wireless network variables significantly impact WNCS design and performance.
• Link performance factors are crucial for evaluating WNCS communication systems.

Purpose of the Study:

• To design and evaluate a WNCS for liquid level control in a coupled tank system.
• To assess the impact of sensor link failure on the control loop's stability.
• To implement a controller that adapts to link instability by selecting alternative communication paths.

Main Methods:

• Developed a WNCS incorporating ISA 100.11a sensors, a network manager, a controller, and a wired actuator.
• Implemented a controller to monitor link stability and switch to alternative links upon detecting instability.
• Conducted preliminary tests to identify the minimum link stability threshold causing control loop errors.

Main Results:

• The WNCS successfully controlled the liquid level in the coupled tank system.
• The adaptive link selection mechanism effectively mitigated the effects of network link disturbances.
• Control system errors remained below the established threshold even under network instability.

Conclusions:

• The proposed WNCS demonstrates excellent performance and robustness in maintaining control loop stability.
• Adaptive link management is a viable strategy for enhancing the reliability of WNCSs.
• The system proves effective in real-world applications requiring stable and secure industrial automation.