Virtual Controller on Intrinsically Safe Field Devices
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Solution Overview
Problem
Conventional industrial control systems lack the capability to deploy virtual control, historian, and HMI functionality to Layer 0 field devices, limiting their resource management and functionality compared to higher layers in the Purdue Model.
Innovation Solution
An intrinsically safe, low-power field device with a processor and memory implementing a virtual controller, enabling distributed control and historian/workstation/HMI functionality by using machine learning and Ethernet-APL technology, allowing Layer 0 devices to connect to industrial networks while maintaining intrinsic safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If virtual controller functionality is deployed to Layer 0 field devices, then device versatility and resource management capability are improved, but device complexity increases
Solution Approach 1:
The control system is segmented into distributed virtual controllers embedded in field devices rather than centralized control. Each field device becomes an independent functional unit with its own processor and memory, enabling localized control decisions while maintaining overall system coordination through the industrial network.
Solution Approach 2:
Field devices are designed with universal multi-functionality, capable of performing both traditional I/O functions and virtual controller functions. The same field device can operate as a simple sensor/actuator or as an intelligent control node depending on configuration, eliminating the need for separate dedicated control hardware.
2Adaptability or versatility
If distributed control functionality is added to field devices, then system flexibility is improved, but power consumption increases
Solution Approach 1:
The virtual controller executes control algorithms periodically rather than continuously, processing data at intervals optimized for the specific application. This periodic execution reduces average power consumption compared to continuous processing while maintaining adequate control responsiveness for the process being controlled.
Solution Approach 2:
The system dynamically adjusts processing parameters such as control cycle frequency and data sampling rates based on process conditions and priority requirements. During normal operation, lower processing frequencies reduce power consumption, while critical events trigger higher frequency processing to maintain control quality.
3Adaptability or versatility
If Layer 0 devices are enabled with virtual controller capabilities, then functionality is improved, but intrinsic safety constraints are challenged
Solution Approach 1:
An intrinsically safe barrier or isolation device serves as an intermediary between the non-intrinsically-safe virtual controller components and the hazardous area. This intermediary limits energy transfer and electrical parameters to remain within intrinsic safety certificates, enabling enhanced functionality while maintaining safety certification.
Solution Approach 2:
The system creates an intrinsically safe operational environment by strictly controlling electrical parameters (voltage, current, power, inductance, capacitance) to remain below ignition thresholds. This controlled 'inert' electrical environment prevents energy from becoming hazardous even in explosive atmospheres, allowing advanced functionality within safety boundaries.
Data Source
AI summary
An Intrinsically Safe (IS) Advanced Physical Layer (APL) based low power field device having a virtual controller implemented thereon. The virtual controller provides distributed control and one or more of historian, workstation, and HMI functionality on the field device.