Where are the status bits for input devices stored in the PLC file structure?

• A. Output Image Table File
• B. Input Image Table File
• C. Memory Image File
• D. I/O Table

Answer: (B)

The status bits for input devices are stored in the Input Image Table File. When the PLC scans inputs, it reads each input signal and represents all of them as a compact binary image of the current input states, which lives in the Input Image Table. This image is what the program uses to evaluate conditions based on inputs. The other storage areas have different roles: the Output Image Table stores the intended states for outputs, the Memory Image File holds internal data and variables, and the I/O Table relates to the hardware mapping and configuration rather than the real-time input states.