EFBs are provided for integrating intelligent I/O modules. The EFBs are designed so that the program can be created as independently as possible from the hardware module used. The project specific information is processed and stored in data structures on the PLC using hardware dependent EFBs (e.g. ERT_854_10). The ERT_854_10 data transfer EFB works with these data structures. It reads the raw values from the Input words (%IWx), processes them and writes the ERT handshake and clock synchronization data to the output words (%MWx). The result of this is that changes of direct addresses or changes of the input or output parameters are automatically evaluated by the EFBs.

Since the evaluation of the configured data is only done once after loading, it is recommended that the EFBs for linking to intelligent modules are divided into several sections.

By division into a configuration section and several processing sections, the CPU load can be reduced because the configuration section only has to be executed once (after a restart or a warm start). The processing section must usually be executed continuously.

The configuration section is controlled with the EN inputs of the corresponding EFB. The EFBs are enabled with internal variables that are set to 1 in the first cycle.