Controller Frame Preloading for Precise Cycle Synchronization
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Solution Overview
Problem
In controller systems, variations in processing time due to data processing capacity affect the timing of frame transmission, leading to decreased synchronization accuracy among devices.
Innovation Solution
The controller schedules part of the software process to be executed in the next control cycle during the current cycle, reducing data processing variation and ensuring timely frame transmission without modifying existing protocol stacks or hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the controller processes a larger amount of data in the software process, then the control functionality is enhanced, but the variation in processing time increases, causing greater variation in frame transmission timing
Solution Approach 1:
The patent applies preliminary action by executing part of the data processing tasks in the current control cycle that would normally be executed in the next control cycle. Specifically, the controller performs preliminary processing of output data including generating communication frames and storing them in a transmission buffer during the current cycle, so that when the next control cycle begins, the transmission process requires minimal processing time. This advance preparation reduces the variation in processing time for the software process, thereby ensuring more consistent frame transmission timing even when processing larger amounts of data.
2Adaptability or versatility
If the processing time variation accounts for a prescribed proportion of the whole processing time, then the software flexibility is maintained, but the frame transmission timing becomes unpredictable, affecting synchronization accuracy
Solution Approach 1:
The patent resolves this contradiction by performing preliminary actions in the current control cycle to prepare data structures, generate communication frames, and populate transmission buffers before the next control cycle's transmission phase. This advance preparation significantly reduces the processing time required during the actual transmission phase, making it predictable and consistent. The synchronization accuracy is thereby maintained because the frame transmission timing becomes deterministic, occurring at a consistent offset from the control cycle start time, while the software retains flexibility in processing larger data amounts during the preparation phase.
Data Source
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AI summary
A controller according to an example of the present disclosure is a controller that controls an object of control, the controller including a processor and a communication circuit. The communication circuit executes transmission of output data to the object of control, and reception of input data from the object of control. The controller controls the object of control by sequentially repeating, on a predetermined control cycle, the transmission of the output data, the reception of the input data, and execution of a control program for generating the output data using the input data. In the transmission of the output data, the processor executes: storing of the output data in a frame, the output data having been generated by the execution of the control program in a previous control cycle; and control of the communication circuit such that the frame, in which the output data is stored, is transmitted to the object of control. The processor executes, in a current control cycle, at least a part of the storing of the output data in a frame that is to be executed in a next control cycle.