Programmable Controller Command Name Conversion via Additional Table
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Solution Overview
Problem
Programmable logic controllers (PLCs) face issues when displaying program lists in command name format due to differences in specifications between PLCs and peripheral devices, leading to unidentified commands and inability to update new command names without upgrading the program display device.
Innovation Solution
A programmable controller system with an additional command information table in the PLC that defines associations between non-corresponding command numbers and names, allowing the program display device to convert and display these commands using this table.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the PLC is updated to a new version with new commands, then the PLC functionality and command set are improved, but the program display device cannot display the new command names because its command name conversion table does not include them
Solution Approach 1:
The command name conversion functionality is segmented into two parts: the original command name conversion table in the program display device, and a new additional command information table in the PLC. This segmentation allows the PLC to store and provide conversion information for new commands without requiring updates to the program display device's internal conversion table.
Solution Approach 2:
The additional command information table acts as an intermediary between the PLC's new commands and the program display device's conversion capability. When the program display device encounters a command number it cannot convert, it requests the corresponding command name from the PLC, which retrieves it from the additional command information table. This intermediary mechanism enables compatibility without direct updates to the display device.
2Device complexity
If the program display device maintains a fixed command name conversion table, then the device structure and data management are simplified, but the device cannot adapt to new PLC versions with new commands
Solution Approach 1:
The solution adds a new dimension to the command name conversion system by introducing a secondary data storage location (the additional command information table in the PLC) rather than expanding the original conversion table in the program display device. This dimensional shift allows new commands to be accommodated in the PLC's memory space, preserving the simplicity of the program display device's internal structure while enabling adaptability to new commands.
3Loss of information
If the program display device requests command names from the PLC for unknown command numbers, then the ability to display all command names is improved, but the communication load and processing time increase
Solution Approach 1:
The additional command information table is pre-populated in the PLC with all necessary command number to command name mappings before runtime. When the program display device needs to convert a command number, the PLC can immediately retrieve the corresponding command name from this pre-prepared table without performing complex calculations or searches, minimizing processing time while ensuring complete information availability.
Data Source
AI summary
In a programmable controller system, a program display device includes: a command name conversion table; a second conversion unit that receives a program list from a programmable controller and converts a command number described in the program list into a command name on the basis of a command name conversion table; a non-corresponding command name acquisition unit that acquires a command name corresponding to a non-corresponding command number among the command numbers described in the program list on the basis of an additional command information table; and a display unit that displays the command name converted by the second conversion unit and the command name acquired by the non-corresponding command name acquisition unit.