Auto-Addressing Modular I/O System for PLC Process Image
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Solution Overview
Problem
Existing modular distributed I/O systems require reconfiguration or reprogramming when I/O modules are added or removed, which complicates the process of maintaining a consistent process image and can lead to errors or warnings due to missing modules.
Innovation Solution
An auto-addressing protocol that allows I/O modules to be omitted without reconfiguration or reprogramming, using a network interface module to automatically assign node IDs and create a process image that accounts for physically present modules, with configuration software indicating the presence or absence of each module through a bit-mapped field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If I/O modules are added or removed from the system, then the system configuration changes to meet user needs, but reconfiguration or reprogramming is required which complicates maintenance and can lead to errors
Solution Approach 1:
The system performs self-identification and self-addressing automatically. When modules are added or removed, the remaining modules automatically adjust their node IDs and the master controller automatically updates the process image without requiring manual reconfiguration or reprogramming by the user.
Solution Approach 2:
The system dynamically changes the node ID parameters of I/O modules based on their physical presence. The auto-addressing protocol modifies address parameters automatically when modules are added or removed, allowing the system to adapt configuration parameters without manual intervention.
2Ease of manufacture
If I/O modules are omitted from the system, then unwanted options can be removed, but the process image becomes inconsistent requiring reprogramming
Solution Approach 1:
The master controller automatically maintains process image consistency by detecting which modules are physically present and automatically adjusting the process image to match the actual configuration. This self-adjusting mechanism prevents errors and warnings while allowing customizations.
Solution Approach 2:
The process image becomes dynamic rather than static. It automatically adapts to the actual physical configuration of modules present in the system, allowing the process image to change seamlessly when modules are added or removed without requiring manual reprogramming.
3Reliability
If manual reconfiguration is performed when modules are removed, then the process image can be updated, but time is lost and errors may occur
Solution Approach 1:
The system performs preliminary automatic detection and adjustment when modules are added or removed. The auto-addressing protocol proactively identifies configuration changes and updates the process image before any errors or warnings can occur, eliminating the need for manual reconfiguration time.
Solution Approach 2:
The system continuously monitors the physical presence of modules and provides feedback to automatically update the process image. This closed-loop feedback mechanism ensures the process image remains accurate without manual intervention, preventing errors and reducing reconfiguration time.
Data Source
AI summary
A modular distributed I/O system that allows one or more modules of an island to be omitted without requiring reconfiguration of the system and a method for auto-addressing the system. The island includes a network interface module that is operably connected to a user interface. The user interface allows a user to indicate for each of the nodes of the island whether the node has an I/O module physically present or not physically present. This allows a constant process image in a system where the process image is dependent upon node ID's of modules, and modules are assigned addresses (i.e., ID's) automatically without using unique markers or signatures.