2 Wired has drawbacks, IO-Link wireless came into being
One of the main reasons for the success of IO-Link is that smart and complex sensors/actuators can be easily connected with a simple and standardized three-wire sensor cable.
2.1 The emergence of IO-Link wireless-based on industrial needs to solve the pain points of wired
With the development of the Industrial Internet of Things (IIoT), communication requirements are also changing rapidly. Machine-to-machine (M2M) communications (such as connected robots, warehouse automation, and factory processing machines) are becoming more and more common, which requires higher availability, better robustness, lower latency and certainty. In this kind of development, cable-based communication simply cannot meet the growing demands of connected devices in terms of flexibility, mobility, and monitoring, resulting in the IO-Link wireless standard.
2.2 IO-Link wireless technology
IO-Link wireless technology is an extension of the IO-Link standard. It defines wireless network communication between sensors/actuators and controllers (usually PLCs) in a factory automation environment. It is the first to meet flexibility and mobility. These requirements, such as performance, latency, etc., provide sensors/actuators with reliable and deterministic wireless communication protocols. IO-Link wireless is designed to provide a similar level of performance and a backward compatible interface with cables, so it is very easy to migrate from a wired system to a wireless system.
IO-Link wireless supports roaming functions, and it is possible to include low-energy battery-powered or energy harvesting sensors in the real-time network. One of the key features of IO-Link wireless is its compatibility with factory and process automation protocols. IO-Link system planning, setting, operation and maintenance standard engineering tools can be used to ensure backward compatibility with wired IO-Link solutions.
2.3 Challenges and characteristics of IO-Link wireless
To achieve the same performance as wired sensor/actuator systems in wireless applications, different requirements must be considered:
(1) The cycle time required to update IO data is less than 10 milliseconds.
(2) The reliability requirements are as high or even higher than wired applications.
(3) More than 30 devices can communicate with a master device through a wireless channel.
(4) The communication should use the open 2.4 GHz frequency band and coexist with other wireless systems on this frequency band.
(5) In an RF area, up to 3 master stations can communicate with up to 120 devices at the same time.
IO-Link wireless has solved the challenges it faces due to the following characteristics:
(1) Provide a deterministic delay of 5 ms communication with 40 nodes (sensors or actuators).
(2) Its reliability is better than 10e^(-9) packet error rate (PER). For example, in an industrial environment, other wireless standards such as WLAN, Bluetooth and Zigbee have reduced reliability by 6 orders of magnitude (~1e^(-3)).
(3) Each master station has up to 5 channel interfaces, and each channel interface has up to 8 devices, that is, a master station can communicate with up to 40 wireless devices.
(4) With 2.4 GHz ISM band radio frequency transceiver, it can coexist with other wireless systems.
(5) A master station can carry up to 40 nodes (devices), that is, in an RF area, 3 master stations can communicate with 120 devices at the same time.
The IO-Link wireless distribution scheme is shown in Figure 3 below.
2.4 IO-Link wireless system composition and system
An IO-Link wireless system usually consists of an IO-Link wireless fieldbus gateway (master station) and an IO-Link wireless device. Devices can be sensors, actuators, RFID readers, valves, motor starters or simple I/O modules. In addition, the standard IO-Link wireless system includes engineering tools for sensor/actuator configuration and parameter assignment.
Figure 4 is an example of an IO-Link wireless and wired system architecture. The architecture of wireless IO-Link looks similar to wired (star topology), but there is no communication cable. IO-Link wireless also supports the bridging function between IO-Link wired to IO-Link wireless. This feature is part of the standard, which allows fast IO-Link devices to wirelessly connect to the master station.
2.5 IO-Link wireless features and advantages
Features
(1) Low latency: 1.6ms (3 cycles, 5ms).
(2) Reliability: Determinism, 6 orders of magnitude more reliable than any wireless system.
(3) Scalable: Each master station has up to 40 wireless devices, and each unit has 120.
(4) Industrial grade: Designed specifically for factory automation, in line with the international standard IEC 61131-9.
(5) Flexibility: Increase flexibility and mobility.
(6) Cost-effectiveness: simplified cable setting.
Advantage
Reduce wiring costs, reduce downtime, reduce maintenance costs, increase mean time between failures, reduce complexity, scale data collection, increase flexibility, and improve safety
About Hongke Industrial Communication:
Hongke is a high-tech company with more than 10 years of experience in the field of industrial automation, especially the industrial bus communication industry. Hongke Industrial Communication Division has in - depth cooperation with world-renowned industrial communication experts [ PEAK-System, Hilscher, Kunbus, SYS TEC, Koenig-Pa, Port, Copa-data, TenAsys, SoC-e, RELYUM] and other in-depth cooperation to provide industry-leading Level industrial bus protocol software and hardware solutions, protocol types include [CAN, CANopen, EtherCAT, Profibus, Profinet, EtherNET/IP, TSN], etc., and product types include code, software, chips, boards, modules, etc. Hongke Industrial Communication is customer-oriented and based on technical capabilities, providing domestic enterprises with the most suitable products and the most satisfactory services. Especially in the context of Industry 4.0, Hongke Industrial Communications keeps pace with the times and launches TSN (Time Sensitive Network) solutions, which will act as a highway-like connection in the trend of the Internet of Everything .
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Author: Hong Branch Industrial Communication --- Jiang Lifeng
Typesetting: Hongke Industrial Communication---Huang Yi
