2
1.2 What is CC-Link
(1) System of FA communication
For FA communication, communication specifications depend on equipment on the communicating end,
content of information and its purpose, however, are roughly divided into information level, controller
level and field level as shown in the following diagram.
(2) Information level
This is mainly used to transmit production information to an information terminal, and is referred to as
“PLC upper network.” Ethernet is mostly used for this level.
(3) Controller level
This frequently handles real time information for a production line, and is referred to as “Network
between PLCs.”
(4) Field level
This is referred to as “PLC lower network,” and is mainly used to save wiring for a control system of
which one controller is in charge, and is positioned as “Wiring save communication.”
This level is largely classified into device level and sensor level.
Information level Controller level Field level
FA computer
Device level
Primary open network
Robot
Remote I/O
Motor
driver
Sensor level
Installed
instrument
Solenoid
valve
Limit switch