In what mode is each I/O module until it receives its I/O configuration?

Each I/O module operates in a 'Waiting' mode until it receives its I/O configuration. In this mode, the module is effectively idle in terms of data processing, but it is actively listening for the configuration data that will define its operational parameters. This waiting state is critical for ensuring that the module correctly initializes and aligns with the overall system setup before engaging in any input or output actions.

Once the I/O configuration is received, the module transitions to a state where it can perform its designated tasks based on the configuration parameters, such as defining the types of signals it will process or specifying the communication protocols. This separation of waiting for configuration ensures stability and proper operation in a programmable logic controller environment, preventing unintended actions or misconfigurations during the initialization phase.