Overview; Memory Configuration; Built-In Flash Memory; Built-In Ram - Omron CJ2 CPU UNIT SOFTWARE User Manual

2 Internal Memory in the CPU Unit
2-1

Overview

2-1-1

Memory Configuration

As shown in the following diagram, the internal memory in the CPU Unit consists of built-in flash mem-
ory and built-in RAM. The built-in RAM is used as execution memory and the built-in flash memory is
used as backup memory.

Built-in Flash Memory

Backup Memory
User Program Area
(Backup)
FB Program Area
(Backup)
Parameter Area
(Backup)
Source and
Comment Areas
Tag Memory
Network Symbols (Tags)
Data is held in these areas
without depending on a
backup battery.
Built-in Flash Memory
The built-in flash memory backs up the user program and parameters, and stores the program source,
comment, and network symbols. Data is held in this area even without depending on a battery. I/O
memory is not backed up.

Built-in RAM

The built-in RAM is the execution memory for the CPU Unit. The user program, parameters, and I/O
memory are stored in the built-in RAM, and the built-in RAM is backed up by battery.
If the battery does not work (e.g., if the battery voltage is low or no battery is installed), the I/O memory
data is lost. The user program and parameters are backed up to the built-in flash memory, so they are
not lost.
2-2
CPU Unit
Built-in RAM
Execution Memory
Automatic backup
User Program Area
Read at startup
Automatic backup
FB Program Area
Read at startup
Automatic backup
Parameter Area
Parameter Area
Read at startup
I/O Memory Areas
Data is backed up in these
areas by a battery.
Backup
Battery
(CJ1W-BAT01)
CJ2 CPU Unit Software User's Manual