RTU Hierarchy Builder Caching Device Data
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Building a device hierarchy in distributed process control systems is a time-consuming process, especially when dealing with a large number of HART devices, as it requires querying each device for identity and tag information, which can take several seconds to several minutes, depending on the network size.
Innovation Solution
Implementing a hierarchy builder in a host machine that operates in conjunction with a HART Hierarchy Reporting Module in a Remote Terminal Unit (RTU), where the RTU caches device information and only the host stores device identities, allowing the host to request and rebuild the hierarchy without directly querying field devices, thus reducing the time required to construct the hierarchy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the host machine directly queries each field device for identity and tag information, then complete device hierarchy information can be obtained, but the process becomes time-consuming and inefficient
Solution Approach 1:
The RTU acts as an intermediary between the host machine and field devices. It collects device information from multiple HART devices and stores it in its database, then provides this pre-collected information to the host machine when requested, eliminating the need for the host to directly query each device
Solution Approach 2:
The RTU performs preliminary action by proactively collecting device identity and tag information from all connected HART devices and storing it in its database before the host machine needs this information. This pre-collection significantly reduces the time required when the host requests hierarchy data
2Reliability
If the host machine queries all field devices to ensure accurate device identity information, then reliable hierarchy data is obtained, but the communication overhead and time consumption increase
Solution Approach 1:
The RTU serves as a trusted intermediary that collects and verifies device information from field devices using standardized HART commands. It stores this validated information in its database and provides it to the host machine, ensuring data reliability while improving efficiency
Solution Approach 2:
The RTU creates copies of device information (identity and tag data) from the field devices and stores these copies in its database. When the host requests hierarchy information, it receives these pre-copied data sets rather than querying original devices, maintaining accuracy while reducing communication overhead
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A system constructs a hierarchy for field devices communicatively coupled to a remote terminal unit (RTU) by retrieving device information from field devices, caching the device information in the memory of the RTU, storing device identities in the memory of a host machine, and obtaining the device information at the host from the RTU in response to subsequent user requests to build the hierarchy, without re-sending commands to retrieve the device information directly to the field devices.