IO-Link is a new, innovative and standardized communication module for sensors and actuators - defined by the Profibus User Organization (PNO). IO-Link technology is based on the point-to-point connection of sensors and actuators to the control system. As such it is not a bus system but constitutes a considerable upgrade of the classic point-to-point connection. Extensive parameter and diagnostics data are transmitted in addition to the cyclic operating data for the connected sensor/actuators. The connection technology used is based on the same 3-wire connecting cables customary in today's standard sensor systems.
Components of an IO-Link system:
Only 2 components are required to use IO-Link:
Compatibility of IO-Link
IO-Link guarantees compatibility between IO-Link-capable modules and standard modules as follows:
Expansion through IO-Link I/O modules
IO-Link compatibility also permits connection of standard sensors/actuators, i.e. conventional sensors/actuators can also be connected to IO-Link. This is done particularly economically with IO-Link I/O modules which enable several sensors/actuators to be connected to the control system simultaneously over one cable.
Another advantage of IO-Link technology is that analog signals are digitized already in the IO-Link sensor itself and are digitally transmitted by the IO-Link communication. As the result, faults are prevented and there is no extra cost for cable shielding.
Integration in STEP7
Integration of the device configuration in the STEP7 environment
Productivity is thus increased throughout all plant lifecycle phases - from configuration and start-up to operation. Thanks to the Siemens IO-Link solution, even sensors and actuators below fieldbus level can be integrated to optimum effect with all their capabilities in the Totally Integrated Automation (TIA) environment.
IO-Link is used in two main applications. First, with IO-Link it is easy to connect even complex sensors with very many parameters to the control system. Second, technology based on IO-Link modules is an optimum subsitute for passive distributors in connecting binary sensors. In both applications, all the diagnostics data are transmitted to the higher-level control system through IO-Link.
Advantages for users (example)
When a complex pressure sensor is used, numerous parameters (e.g. threshold values, hysteresis values) are set during commissioning for the plant to sun smoothly. These data are sent through IO-Link to the control system and stored there. If this sensor fails and has to be replaced, all that is required is to exchange the sensor itself. The necessary parameters are then called up from the control system and loaded through IO-Link into the sensor. Without IO-Link, the sensor would have to be parameterized anew at great cost of time and effort.