Patent ID: 7574268

Claim:
A function unit providing functionality for a terminal module of a control system in an industrial automation system, each terminal module having an interface for connecting to a function module and a contact for connecting to the function unit, the function unit comprising: a left connector for connecting to a left terminal module; a right connector for connecting to a right terminal module, wherein the function unit allows at least two terminal modules to be connected in a chain by mounting the left and right connectors to the left and right terminal modules respectively, wherein the function unit provides a function to connected terminal modules such that the terminal modules do not require reassembly when the functionality is changed; wherein the function unit comprises a visual indicator that visually identifies the function of the function unit; wherein the left and right terminal modules are adjacent; wherein a maximum width of the function unit is a width of the terminal module; wherein the function unit is a supply unit having terminals to connect a supply voltage providing a voltage connection to the left and right connectors, thereby a voltage is supplied to the right and left terminal modules when the function unit is connected to the right and left terminal modules; and wherein an additional terminal for a PE (protective earth) connection with a minimum cross-sectional area of 2.5 mm^2 is provided for the PE connection.