Data Transfer Device for Real-Time FA Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current data transfer devices in FA systems face inefficiencies due to high overhead in polling communication methods, resulting in long data transfer intervals and inability to acquire device data in real-time, especially given the high-speed updates in PLCs.
Innovation Solution
A data transfer device with a collection-interval storage unit, data collection unit, transfer-interval storage unit, temporary storage unit, and data transferring unit that collectively transfers control data at intervals set by the high-order device, allowing for faster and more frequent data collection and transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a polling communication method is adopted for data transfer, then the data transfer device can maintain simple communication control, but the overhead for transmitting data transfer requests becomes large and the data transfer interval becomes long
Solution Approach 1:
The data transfer device preliminarily collects control data from the PLC at a short cycle (e.g., 1ms) and stores it in a storage unit before the host computer requests it. This preliminary data collection action eliminates the need for time-consuming polling requests at each data access, thereby reducing the data transfer interval while maintaining simple communication control.
2Adaptability or versatility
If data is collected and transferred individually at each request, then the data can be transferred on demand, but the data transfer efficiency becomes low and real-time data acquisition is not achieved
Solution Approach 1:
The data transfer device merges multiple individual data collection operations into a single continuous collection process that runs at a short cycle. Instead of collecting and transferring data individually at each host computer request, the system continuously collects control data from the PLC at predetermined intervals and stores it, thereby improving data transfer efficiency while maintaining the flexibility to serve multiple requests.
Solution Approach 2:
The data collection process is made continuous by collecting control data from the PLC at every cycle of the predetermined short interval (e.g., 1ms), regardless of whether the host computer has issued a request. This continuous useful action ensures that data is always ready for immediate transfer, achieving real-time data acquisition while improving overall transfer efficiency.
3Speed
If the collection interval is shortened to match PLC update speed, then real-time data acquisition is enabled, but the data transfer overhead increases with traditional polling methods
Solution Approach 1:
The system performs preliminary data collection at a short cycle (matching PLC update speed) and stores the data in advance. When the host computer requests data, it is immediately transferred from storage without requiring additional communication overhead for polling. This preliminary action enables real-time data acquisition while eliminating the energy-wasting repeated request-response cycles of traditional polling.
Solution Approach 2:
The data transfer device serves itself by automatically collecting and storing control data from the PLC at predetermined intervals without needing the host computer to initiate each collection. This self-service mechanism reduces communication overhead because the data collection process is autonomous and does not require continuous polling requests from the host computer.
Data Source
AI summary
A data transfer unit includes: a collection-interval storage unit that storing therein a collection interval set by the host computer; a data collection unit reading a collection interval stored in the collection-interval storage unit and collecting device data at the read collection interval; a transfer-interval storage unit storing therein a transfer interval set by the host computer, which is equal to or larger than the collection interval; a ring buffer accumulating and storing therein device data that are collected by the data collection unit and have not been transferred to the host computer by a data transferring unit; and a data transferring unit reading a transfer interval stored in the transfer-interval storage unit, and collectively transfers device data accumulated and stored in the ring buffer to the host computer at the read transfer interval.