7
Internal Structure of the CPU Unit Section 1-3
PLC Setup The PLC Setup is used to set various initial or other settings through software
switches.
DIP Switches DIP switches are used to set initial or other settings through hardware
switches.
Memory Cards Memory Cards are used as needed to store data such as programs, I/O mem-
ory data, the PLC Setup, and I/O comments created by Programming
Devices. Programs and various system settings can be written automatically
from the Memory Card when power is turned ON (automatic transfer at star-
tup).
Flash Memory (CS1-H,
CJ1-H, or CJ1M CPU Units
Only)
With the CS1-H, CJ1-H, or CJ1M CPU Units, the user program and parameter
area data, such as the PLC Setup, are automatically backed up in the built-in
flash memory whenever the user writes data to the CPU Unit. This enables
battery-free operation without using a Memory Card. I/O memory, including
most of the DM Area, are not backed up without a battery.
1-3-2 Block Diagram of CPU Unit Memory
CPU Unit memory (RAM) is comprised of the following blocks in the CS/CJ
Series:
• Parameter area (PLC Setup, registered I/O table, routing table, and CPU
Bus Unit settings)
• I/O memory areas
• The user program
Data in the parameter area and I/O memory areas is backed up by a Battery
(CS Series: CS1W-BAT01, CJ1-H: CPM2A-BAT01), and will be lost if battery
power is low.
The CS1-H, CJ1-H, or CJ1M CPU Units, however, provide a built-in flash
memory for data backup. The user program and parameter area data are
automatically backed up in the built-in flash memory whenever the user writes
data to the CPU Unit from a Programming Device (e.g., CX-Programmer or
Programming Console), including the following operations: Data transfers,
online editing, transfers from Memory Cards, etc. This means that the user
program and parameter area data will not be lost even if the battery voltage
drops.
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