Memory is the component that stores information, programs, and data in a PLC. See more..... projuktiponnoThe process of putting new information into a memory location is called writing. The process of retrieving information from a memory location is called reading.Types of MemoryThe common types of memory used in PLCs areRead Only Memory (ROM) andRandom Access Memory (RAM).A ROM location can be read, but not written. ROM is used to store programs and data that should not be altered.For example, the PLC’s operating programs are stored in ROM. A RAM location can be read or written. This means the information stored in a RAM location can be retrieved and/or altered.Ladder logic programs are stored in RAM. When a new ladder logic program is loaded into a PLC’s memory, the old program that was