MAXREFDES36#: IO-Link 16-Ch Digital Input Hub

The MAXREFDES36# is an IO-Link 16-channel digital input hub that fits on a small 53.75mm x 72mm printed circuit board (PCB). Maxim Integrated and Technologie Management Gruppe Technologie und Engineering (TMG TE) collaborated in designing the MAXREFDES36# as an IO-Link version 1.1/1.0 compliant digital input hub reference design. The MAXREFDES36# design consists of an industry standard Maxim Integrated IO-Link device transceiver (MAX14821), an efficient high-voltage step-down converter (MAX17552), a Renesas® ultra-low-power 16-bit microcontroller (RL78) utilizing TMG TE’s IO-Link device stack and two Maxim Integrated digital input serializers (MAX31913).

Programmable logic controllers (PLCs) and distributed control systems (DCSs) use more digital inputs than any other input signal type combined. Running wires in parallel back to the PLC for industrial digital inputs is not only expensive but also creates a wiring rat’s nest that is difficult to maintain. Field buses improved the situation considerably by moving the I/O interface from the PLC to a remote I/O hub mounted close to the field sensors. However, the lack of a single, universally accepted field bus has also created confusion, training challenges, high costs, and compatibility issues among equipment.

IO-Link is the first open, field bus agnostic, low-cost, point-to-point serial communication protocol used for communicating with sensors and actuators that has been adopted as an international standard (IEC 61131-9).2 IO-Link finally standardizes interoperability of industrial equipment from all over the world. IO-Link can function directly from the PLC or can be integrated into all standard field buses, quickly making it the defacto standard for universally communicating with smart devices like the MAXREFDES36#.