Servo Controller I/O Unit Bypassing Internal Bus for Signal Latency
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Solution Overview
Problem
Numerical control devices experience delays in transmitting high-priority input signals, such as emergency stop signals and completion signals, due to the need for these signals to pass through a shared bus, which increases communication time and affects the responsiveness of servo controllers in machine tools and robots.
Innovation Solution
A direct internal communication path between the servo controller and the I/O unit within the integrated circuit, bypassing the internal bus, allows for immediate transmission of urgent input signals, reducing reliance on the shared bus and minimizing communication delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If signals are transmitted through the shared internal bus in the integrated circuit, then the device complexity is reduced by integrating components, but the communication time for high-priority input signals increases causing delays
Solution Approach 1:
The patent segments the communication paths into two types: shared bus for general data transmission and dedicated direct communication paths for high-priority signals. This segmentation allows the system to maintain integration benefits while providing expedited routes for emergency stop signals, completion signals, and other time-critical inputs, thereby resolving the contradiction between device complexity reduction and communication time for priority signals.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of dedicated communication paths that act as mediators for high-priority signals. These direct paths serve as intermediate transmission channels between the I/O unit and servo controller, bypassing the shared bus for critical signals while maintaining the integrated circuit structure, thus reducing communication time without significantly increasing overall device complexity.
2Device complexity
If a shared bus is used for all signal transmissions, then the integrated circuit structure is simplified, but the responsiveness of servo controllers to emergency signals deteriorates
Solution Approach 1:
The patent applies local quality by providing different communication path qualities for different signal types. High-priority signals such as emergency stop signals and completion signals are routed through dedicated direct communication paths with higher reliability and faster transmission, while other signals use the shared bus. This localized optimization of communication quality resolves the contradiction between simplified integrated circuit structure and improved responsiveness for critical signals.
3Device complexity
If high-priority signals must pass through the shared bus, then the bus structure remains simple, but the communication speed for urgent signals decreases affecting cycle time
Solution Approach 1:
The patent implements a dynamic communication architecture where the transmission path for signals is determined by their priority level. High-priority signals dynamically select dedicated direct communication paths for faster transmission, while standard signals use the shared bus. This dynamic path selection reduces cycle time for urgent operations without requiring a completely complex bus structure, thereby resolving the contradiction between simple bus structure and improved productivity.
Data Source
AI summary
A numerical control device includes a CPU for outputting a position command value of a servomotor; an IC including a servo controller for outputting a current command value to an amplifier for driving the servomotor, and an I/O unit for inputting and outputting an external signal; a DSP for reading the position command value and performing control so as to move the servomotor to a position indicated by the position command value; and an inter-device communication path between the CPU and the IC. The IC includes an internal bus connected to a communication interface connected to the inter-device communication path, and the I/O unit; and an internal communication path for directly transmitting a signal between the servo controller and the I/O unit without passing through the internal bus.