Servo Encoder Wiring Simplification via Signal Merging

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Solution Overview

Problem

In servo systems where the servo driver is remote from the servo motor, long cables are required for sensor wiring, leading to increased complexity and labor in wiring work, as well as higher costs due to longer cable lengths.

Innovation Solution

An encoder is used with a communication unit that transmits feedback and detected signals through a common communication cable, including power and control terminals, to reduce the length of sensor wiring by integrating these functions into a single cable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the servo driver is placed remote from the servo motor for layout reasons, then the flexibility of system layout is improved, but the cable length for sensor wiring increases leading to increased wiring complexity and labor

Engineering Contradiction:
Improvelayout flexibilityVSAvoidwiring complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions (encoder feedback, sensor detection, power supply, and control signal transmission) into a single integrated cable system. The encoder unit serves as an intermediary that receives detected signals from sensors near the motor and transmits them along with feedback signals to the servo driver through a common communication cable, eliminating the need for separate sensor cables.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The communication cable is designed to perform multiple functions simultaneously: transmitting encoder feedback signals, carrying sensor detected signals, providing power supply, and transmitting control signals. This multi-functional cable reduces the number of separate connections needed and simplifies the overall wiring architecture.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If long cables are used for sensor wiring due to remote servo driver placement, then the layout flexibility is maintained, but the cost of cables and wiring work increases

Engineering Contradiction:
Improvelayout flexibilityVSAvoidcable length
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The system is segmented into functional units: the encoder unit positioned near the motor serves as a local signal processing center that receives sensor inputs and generates feedback signals. This segmentation allows the use of shorter local cables between sensors and the encoder, while the communication cable connecting the encoder to the servo driver can be optimized in length and routing.

Inventive Principle:
Principle #1Segmentation

3Reliability

If multiple separate cables are used for feedback signals and sensor detected signals, then signal transmission reliability is maintained, but the wiring work requires more time and labor

Engineering Contradiction:
Improvesignal transmission reliabilityVSAvoidwiring time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

Multiple signal types (feedback signals and detected signals) are merged into a single communication cable for transmission between the encoder and servo driver. The encoder unit acts as a signal consolidation point that combines multiple input signals from sensors with the feedback signal, transmitting them together through one cable rather than requiring separate cables for each signal type.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3572902B1Encoder and servo system
Publication Date: 2021.10.27 OMRON CORP
  • EP3572902B1 patent drawingFigure 1
  • EP3572902B1 patent drawingFigure 2
  • EP3572902B1 patent drawingFigure 3

AI summary

The present invention provides a configuration which enables an improvement in the workability of wiring of a sensor in a servo system. An encoder (31) detects the operation of a motor (30) driven by a servo driver (2), and generates a feedback signal (FB) indicating the detected operation. Further, the encoder (31) receives detected signals (DET1 to DET4) output from sensors (61 to 64) for detecting an object (53) driven by the motor (30) via sensor cables (71 to 74). The encoder (31) outputs the feedback signal (FB) and the input detected signals (DET1 to DET4) to the outside.