Did you know that IO-Link is backward compatible with binary sensors?
The IO-Link communication interface is standardized in international standard IEC 61131-9. One of the initial goals of the multi-company standardization initiative was to create an interface that takes into consideration the existing architectures and the typical connection level in the lower field level. The point-to-point connection familiar there was simply taken over in IO-Link, complete with the standard cabling.
Moreover, the standard defines a standard I/O mode (SIO) in addition to the communication mode (COM). The SIO mode describes that an IO-Link master can also take up a digital input/output function according to IEC 61131-2 Type 1. Binary IO-Link sensors output digital switching signals according to IEC 60947-5-2 after switch-on using the connection C/Q provided for IO-Link communication.
The advantages are obvious: The wiring level in the lower field level can be used one-to-one without limitations for IO-Link connections and binary signals. A better degree of utilization can be achieved for the IO-Link master because IO-Link and binary sensors can be connected to a master module in a mixed operation. Binary IO-Link sensors, on the other hand, can also be operated with conventional digital inputs.
But does it make sense to operate an IO-Link sensor as a binary sensor? Yes, for example, because IO-Link is used as a standardized parameter assignment interface. With IO-Link a universal tool world and the device description IODD that exists for all IO-Link devices are available for the first time. It is therefore possible to make settings or ‘clone’ sensors efficiently even outside the actual application. The devices with preassigned parameters can then be integrated in a non-IO-Link application without manual setting.