The ECO Fieldbus Coupler is designed for applications with a low data width in the process image. These are primarily applications that use digital process data or only low volumes of analog process data. The system supply is provided directly by the coupler. The field supply is provided via a separate supply module. The CANopen Fieldbus Coupler detects all connected I/O modules and creates a local process image.The local process image is divided into two data zones containing the data received and the data to be sent. The process data can be sent via the CANopen bus to a control system for further processing. The process output data is sent via the CANopen bus. The data of the analog modules is stored in the PDOs according to the order in which the modules are connected to the coupler. The bits from the digital modules are sent byte by byte and also mapped in the PDOs. If the amount of digital I/O information exceeds eight bits, the coupler automatically starts with a new byte. All entries of the object directory can be mapped as required in the five Rx PDOs and five Tx PDOs. The complete input and output process image can be transmitted using SDOs. Spacer modules can be set via software.