What is IO-Link and How Does It Work?
IO-Link refers to a globally standardized technology certified according to IEC 61131-9 for connecting field devices such as actuators or sensors to the higher-level control system. IO-Link is an independent communication protocol that can be easily integrated into standard fieldbus systems on the market. "IO" stands for Input and Output. The communication is bidirectional, meaning it occurs in both directions, allowing for the transfer of cyclic and acyclic data. IO-Link is the first globally standardized IO technology that enables digital communication with sensors and actuators.
The IO-Link master receives signals from actuators and sensors, processes them, and then outputs them in a modified form to transmit commands, for example. IO-Link is based on the 3-wire connection method and is not a fieldbus, but rather a point-to-point communication system between the peripheral interface and the field device.
IOD stands for IO Device and refers to the devices in the IO-Link system. IODD stands for IO Device Description and refers to the product descriptions of the devices, where the parameter information of the sensors and actuators is defined.
Structure of an IO-Link System
An IO-Link system consists of various components: IO-Link devices such as sensors or actuators, and an IO-Link master. An IO-Link master can have multiple IO-Link ports, each capable of connecting to one IO-Link device. In total, up to eight devices can be connected. The IO-Link master acts as an interface between the control system and field devices, ensuring reliable exchange of device, process, and diagnostic data. Different types of data can be transmitted during the exchange.
Advantages of IO-Link
- High Economic Efficiency: Cost-effective due to simplified wiring and reduced installation efforts.
- Excellent Diagnostic Capability: Provides detailed diagnostics down to the sensor or actuator level.
- Easy Integration: Can be easily integrated into common fieldbus systems (e.g., PROFIBUS) and automation systems.
- Fast Device Replacement: Enables quick device replacement through automatic reparameterization, which is beneficial for maintenance.
- Command Transmission: The IO-Link master can transmit commands, read data, and also evaluate it.
- High Compatibility: Being a standardized protocol ensures compatibility across devices from different manufacturers.
- Seamless Communication: Enables consistent communication between the actuator/sensor and the control system.
- 3-Wire Connection Method: Allows circuits over longer distances.
- Fast Data Transmission: Point-to-point connections enable very fast data transmission.