The X-NUCLEO-PLC01A1 is an industrial input/output evaluation board which expands the STM32 Nucleo board functionality with a PLC (programmable logic controller) function subset. It is compatible with the Arduino UNO R3 connector layout and is designed around VNI8200XP (solid state relay) and CLT01-38SQ7 (octal digital termination array). The X-NUCLEO-PLC01A1 interfaces with the STM32 MCU via the SPI peripheral. Moreover, it is equipped with a set of diagnostic and activity LEDs to facilitate application debugging. It can accept other STM32 plug-on expansion boards to further extend the STM32 Nucleo board functionality. The X-NUCLEO-PLC01A1 allows the rapid evaluation of the ICs on board performing a basic set of PLC operations in conjunction with the X-CUBE-PLC1 software package. X-NUCLEO-PLC01A1 is not intended to evaluate the single devices at their full specifications. VNI8200XP includes advanced protection and fault detection features. CLT01-38SQ7 provides protection and isolation in industrial operating conditions as well as an 'energy-less' status indication for each of the eight input channels, featuring minimal power consumption; it is designed for situations that are required to pass the IEC61000-4-2 8 kV and 15 kV test standards. Both the CLT01-38SQ7 and the VNI8200XP are designed to meet the most common industrial requirements (i.e. IEC61000-4-2, IEC61000-4-4, IEC61000-4-5 or IEC61131-2); to eveluate them further, refer to the single-product evaluation boards, available at www.st.com.