Programmable Logic Controller (PLC) Practice Test

The datafile memory holds the runtime data a PLC program uses during execution. It includes the current input and output status (the I/O image), the processor’s status (such as RUN or fault indicators), and the values of internal bits and numerical data like flags, counters, timers, and data registers. In short, it’s where the program reads and writes data as it runs.

This is different from where the program code itself resides (program memory) and not the place for network configuration or only “user data.”