PLc Memory & Addressing

The document discusses PLC memory, including that it consists of the operating system, firmware, and programs and data used by the programmer. It notes that programs can be saved externally but data exchange is too slow for interfacing. Memory includes volatile and non-volatile areas, with volatile memory requiring a battery or capacitor to hold programs and data when power is off. Firmware is stored in non-volatile memory and updated using manufacturer tools. Ladder logic programs are stored in RAM memory and overwrite the previous program when a new one is loaded. Memory capacities in PLCs vary and are expressed in kilobytes or bytes.