ABSTRACT
The increased use of microcontrollers embedded in low-cost sensors and actuators has provided opportunities for adding diagnosis and configuration data to support increasing application requirements. The single-drop digital communication interface technology for small sensors and actuators IO-Link (also known as SDCI in IEC 61131-9) defines a migration path from the existing digital input and digital output (DI/DO) interfaces for switching 24 V Devices, as defined in IEC 61131-2, toward a point-to-point communication link. The driving force for a new technology called IO-Link has been the need of these low-cost sensors and actuators to exchange the diagnosis and configuration data with a controller (PC or PLC) using a low-cost digital communication technology while maintaining backward compatibility with the current DI/DO signals. The IO-Link technology defines a generic interface for connecting sensors and actuators to a Master unit, which may be combined with gateway capabilities to become a fieldbus remote I/O node or via an adapter to personal computers or drives.
