Programmable Controller Background Logging for Deterioration Diagnosis
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Solution Overview
Problem
The existing programmable controller systems require significant effort and time to determine deterioration diagnosis threshold values and collect reliable data, especially when introducing external equipment deterioration diagnosis functions, leading to increased cycle time and variability in system operation.
Innovation Solution
A programmable controller system with a monitoring apparatus that passively monitors communication data between the programmable controller apparatus and remote input/output apparatus, allowing for automatic notification of deterioration diagnosis results without involving the user program, and includes a threshold value setting support apparatus that collects data and determines threshold values using statistical methods, reducing the need for extensive logging processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a logging program is installed in the user program to transfer time lag data to the PLC apparatus for storing, then the deterioration diagnosis function can be implemented, but the effort for producing user program increases and the cycle time is delayed
Solution Approach 1:
The logging function is extracted from the user program and implemented as an independent background thread within the PLC apparatus. This allows the deterioration diagnosis data collection to occur autonomously without requiring user program modifications, thereby resolving the contradiction between achieving reliable deterioration diagnosis and maintaining high program production efficiency.
2Reliability
If a logging program is installed in the user program to transfer time lag data to the PLC apparatus for storing, then the deterioration diagnosis function can be implemented, but the cycle time is delayed due to executing maintenance user program simultaneously with original control user program
Solution Approach 1:
The PLC apparatus operations are segmented into distinct functional modules: the original control user program executes cyclically for real-time control, while the logging function operates as a separate background thread for data collection. This segmentation allows both functions to run concurrently without interfering with each other's timing, thus maintaining the original cycle time while enabling reliable deterioration diagnosis.
3Reliability
If the logging process is carried out by transferring time lag data to the PLC apparatus and storing in the user program, then the deterioration diagnosis data can be collected, but the data collection requires extensive time (one or two months) and significant effort
Solution Approach 1:
The PLC apparatus autonomously collects and stores time lag data through its background logging thread without requiring external intervention or manual data transfer. The system self-services by automatically performing the data collection, processing, and storage functions that would otherwise require significant user effort and extended time periods, thereby reducing both the effort and time required for reliable data collection.
Data Source
AI summary
A programmable controller system includes a programmable controller apparatus, a remote input and output apparatus connected to the programmable controller apparatus via a field bus and a monitoring apparatus configured to be located on a communication path between the programmable controller apparatus and the remote input and output apparatus and to monitor a communication data therebetween. The monitoring apparatus includes a rewritable tag for prescribing a condition for issuing a transmission request command with respect to an external equipment deterioration diagnosis and a command issuing part issues a transmission request command required for the external equipment deterioration diagnosis with reference to the tag. A preferable data logging operation is carried out properly without any PLC operation.