IO Link Contact-Free Transmission Delay Compensation
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Solution Overview
Problem
The existing IO link transmission systems experience significant delays due to media transitions between cable-based and contactless communication, leading to potential communication interruptions and non-compliance with IO link specifications, especially when using high-performance bus systems like PROFIBUS-DP, Interbus, and CANopen, which are not economically viable for sensor-actuator levels.
Innovation Solution
The method involves monitoring the communication between the IO link master and device, intercepting the MinCycleTime inquiry response, and adding the delay caused by the contactless transmission system to the MinCycleTime, ensuring that the communication cycle is extended to prevent interruptions and maintain compliance with IO link standards, particularly by using a BIC coupler to manage and compensate for the contactless transmission delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If cable-free transition with inductive coupling is used for IO link communication, then installation space requirements are reduced and wiring complexity is decreased, but transmission delays occur due to media transitions between cable-based and contactless communication
Solution Approach 1:
The system pre-determines the minimal cycle time required for contactless communication and compensates for transmission delays by adjusting the MinCycleTime parameter before communication occurs. This preliminary adjustment ensures that the IO link master accounts for the additional time needed for media transitions, preventing communication interruptions while maintaining the benefits of cable-free installation.
2Speed
If high-performance bus systems like PROFIBUS-DP or CANopen are used at sensor-actuator level, then communication speed and performance are improved, but installation costs and economic viability deteriorate
Solution Approach 1:
The invention employs cost-effective unshielded three- or five-wire standard cables combined with a contactless coupling system at the sensor-actuator level, rather than deploying expensive high-performance bus systems throughout the entire installation. This approach achieves the necessary communication performance for sensor-actuator applications while significantly reducing material and installation costs compared to using industrial-strength bus systems like PROFIBUS-DP or CANopen.
3Productivity
If MinCycleTime is not adjusted for contactless transmission delays, then communication cycle duration is kept short and productivity is maintained, but communication interruptions and collisions occur
Solution Approach 1:
The system dynamically adjusts the MinCycleTime parameter based on the detected transmission medium. When contactless communication is active, the MinCycleTime is increased to account for the additional delays introduced by inductive coupling and media transitions. This parameter adaptation ensures reliable communication by preventing data collisions while minimizing the impact on overall communication cycle efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures transparent and uninterrupted data transfer, maintaining compliance with IO link standards and enabling bidirectional communication, effectively preventing collisions and ensuring that IO link devices operate independently of manufacturer-specific couplers, thus optimizing the contact-free transmission system.
Implementation Method 1
Such a cable-free transition can be carried out by means of inductive coupling, e.g. by means of a per se known 'Balluff Inductive Coupler' (BIC)
Data Source
AI summary
In a method and a control device for the operation of a transmission system for an IO link, wherein at least one cable-free transition between an IO link master and at least one IO link device is provided, and wherein the IO link device provides a minimal cycle time for a communication cycle, it is particularly provided that the minimal cycle time provided by the IO link device is increased in such a manner that a temporal delay caused by the cable-free transition is added to the minimal cycle time.