Bidirectional Serial Loop for Servo Amps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing servomotor control systems face challenges in maintaining low total transmission time during serial communication between an NC device and servo amps due to delays in physical layers, especially at high bit rates, which can lead to data collisions and increased wire complexity.
Innovation Solution
Implementing a loop configuration with bidirectional serial communication cables and splitting command and feedback data into halves to be sent in alternating directions, allowing simultaneous transmission and reducing the overall transmission time by using gigabit Ethernet for efficient data transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a daisy chain configuration with unidirectional serial communication is used, then wire complexity is reduced, but total transmission time increases significantly due to sequential data forwarding through each servo amp
Solution Approach 1:
The command data packet is segmented into two halves, with the first half sent in a clockwise direction and the second half sent in a counter-clockwise direction. This segmentation allows parallel transmission paths, reducing the sequential forwarding delay that occurs in traditional daisy chain configurations where data must pass through each servo amp one by one.
Solution Approach 2:
The patent introduces a bidirectional communication dimension to the traditional unidirectional daisy chain. By establishing two-way communication capability at each servo amp interface, the system transforms a single-path sequential transmission into a multi-path parallel transmission, effectively reducing transmission time without increasing wire complexity.
2Productivity
If high bit rate serial communication is used to meet high loop execution frequency, then positioning accuracy and feed rate improve, but physical layer delays cause data collisions and increase transmission time
Solution Approach 1:
The patent implements periodic bidirectional data transmission where command data halves are alternately sent in clockwise and counter-clockwise directions. This periodic alternating transmission prevents data collisions by ensuring that opposing data streams are transmitted in organized time slots, allowing high bit rate communication to maintain accuracy without collision-induced delays.
Solution Approach 2:
The system performs preliminary address identification and data validation at each servo amp before forwarding data. This preliminary action ensures that data is correctly routed and validated early in the transmission process, preventing collisions and retransmissions that would otherwise occur at higher bit rates.
3Productivity
If bidirectional serial communication with loop configuration is used, then data transmission efficiency improves, but wire complexity increases
Solution Approach 1:
Each servo amp interface is designed with universal bidirectional communication capability, allowing the same physical connection to handle both clockwise and counter-clockwise data transmission. This multi-functionality eliminates the need for separate dedicated wires for each direction, maintaining wire simplicity while achieving bidirectional communication efficiency.
Data Source
AI summary
A communication control system and method of communicating between a numerical control device and a plurality of servomotors, includes connecting the numerical control device to a plurality of servoamps of the plurality of servomotors in a loop configuration via bi-directional serial communication cables, splitting command data in the numerical control device, outputting a first portion of command data to one of the plurality of servoamps from the numerical control device in a counter-clockwise direction and a second portion of command data to one of the plurality of servoamps from the numerical control device in a clockwise direction, splitting feedback data in one of the plurality of servoamps, transmitting a first portion of feedback data to the numerical control device in a counter-clockwise direction from the one of plurality of servoamps in response to the first portion of command data, and transmitting a second portion of data to the numerical control device from the one of the plurality of servoamps in a clockwise direction in response to the second portion of command data, whereby splitting command data and feedback data and transmitting the split portion of data in clockwise and counter-clockwise directions to a servoamp reduces total transmission time.