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FX3G/FX3U/FX3UC Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
2 Overview (Sequence Program)
2.6 Program Memory and Devices
2.6 Program Memory and Devices
2.6.1 Memory structure
1. In FX3U/FX3UC PLCs
FX3U/FX3UC PLCs are equipped with the RAM memory as standard.
By mounting a memory cassette, the memory type can be changed.
1) When using the built-in memory (without attached memory cassette)
2) When using an attached memory cassette (dose not use the built-in program memory)
CPU System ROM
Built-in program memory
(RAM)
Parameter
File register (D)
Comment
Sequence program
Memory cassette
(Flash memory)
Not attached
Built-in device memory (RAM)
[Bit device memory]
Data register (D)
Timer present value register (T)
Counter present value register (C)
Index register (V, Z)
Contact image memory
Input relay (X) Output relay (Y)
Auxiliary relay (M) State relay (S)
Timer contact and time counting coil
Counter contact, counting coil, and reset coil Extension register (R)
[Data memory]
CPU System ROM
Built-in program memory
(RAM)
Not used
Memory cassette
(Flash memory)
Parameter
File register (D)
Comment
Sequence program
Extension file register (ER)
The PLC automatically recognizes attachment of a
memory cassette (when the power is turned ON),
and disconnects the built-on program memory.
(Priority is given to the memory cassette.)
Built-in device memory (RAM)
[Bit device memory] [Data memory]
Transfer and initialization by
instructions
Contact image memory
Input relay (X) Output relay (Y)
Auxiliary relay (M) State relay (S)
Timer contact and time counting coil
Counter contact, counting coil, and reset coil
Data register (D)
Timer present value register (T)
Counter present value register (C)
Index register (V, Z)
Extension register (R)