Connection of input and / or output modules to a fieldbus with a higher-level controller

An I/O Module comprising:

• an input interface that connects to at least one sensor for input of an input signal and an output interface that connects to at least one actuator for output of an output signal;
• a data interface that connects to a sub-bus for the transmission of an input datum and output datum to and from a fieldbus head;
• and
• a control unit connected to the data interface and connected to the input interface and the output interface,
• wherein the control unit is set up to process the input datum and the output datum and to exchange the input datum and the output datum via the data interface,
• wherein the control unit is set up to store a predetermined input value and a predetermined output value,
• wherein the control unit is set up to receive a control value via the data interface and, based on the control value, to switch the I/O module into a first operating mode (normal mode) or into a second operating mode (control mode),
• wherein in the first operating mode (normal mode), the output datum is received via the sub-bus and the output signal is based on the output datum and is output via the output interface, and the input signal is received via the input interface and the input datum is based on the input signal and is output to the sub-bus, and
• wherein in the second operating mode (control mode), the output datum is received via the sub-bus and the output datum is replaced with the predetermined output value stored in the control unit and the output signal that is based on the predetermined output value is output via the output interface and the input datum is replaced by the predetermined input value stored in the control unit and the predetermined input value is output to the sub-bus.