LCM-Based Message Synchronization for I/O Modules
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Industrial process control and automation systems face data synchronicity issues due to unsynchronized system clocks in I/O modules, leading to communication challenges when new modules are added, and existing synchronization methods may not achieve precise clock synchronization.
Innovation Solution
A method and system that utilize a least common multiple (LCM) to synchronize messages by determining scan rates of I/O modules, transmitting read request messages with an align index field, and incrementing it until it reaches the LCM, allowing only synchronized modules to respond, thus eliminating the need for precise clock synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional clock synchronization methods are used, then system complexity is reduced, but measurement precision and synchronization accuracy deteriorate
Solution Approach 1:
The patent introduces an alignment field as an intermediary mechanism in message transmission. This field acts as a mediator that carries synchronization information without requiring complex clock synchronization protocols. The alignment field enables precise message alignment between controllers and I/O modules by providing a simple incremental counter that can be easily processed, thereby achieving high synchronization accuracy while maintaining system simplicity.
2Adaptability or versatility
If I/O modules are added at different times without synchronization, then system adaptability improves, but communication reliability deteriorates
Solution Approach 1:
The patent implements preliminary alignment by pre-configuring the alignment field increment logic in each I/O module based on its scan rate. When modules are added to the system at different times, they already have the capability to generate and process alignment fields correctly. This preliminary configuration ensures that new modules can be integrated without disrupting communication reliability, as they automatically participate in the synchronization mechanism from the moment of addition.
3Measurement precision
If message alignment is implemented using LCM of scan rates, then synchronization accuracy improves, but processing time increases
Solution Approach 1:
The patent employs periodic action by having the main controller increment the alignment field in each communication cycle and having I/O modules check for alignment conditions based on their scan rates. This periodic increment and check mechanism achieves precise message alignment at the least common multiple of scan rates without requiring complex real-time calculations, as the alignment condition naturally recurs periodically. This approach minimizes processing time while maintaining high synchronization accuracy.
Data Source
AI summary
A method includes determining a scan rate associated with each of a plurality of input/output (I/O) modules. The method also includes transmitting a read request message to at least one expansion controller that controls the plurality of I/O modules, the read request message having an align index field. The method further includes receiving a reply message from the at least one expansion controller for each of the I/O modules for which a value of the align index field of the read request message is an even multiple of the associated scan rate. The method also includes incrementing the value of the align index field. In addition, the method includes repeating the transmitting, receiving, and incrementing until the value of the align index field is greater than a threshold, wherein the threshold is a least common multiple of the scan rates of the plurality of I/O modules.