Extension Register [R] And Extension File Register [Er]; Numbers Of Extension Registers And Extension File Registers; Data Storage Destination And Access Method - Mitsubishi Electric MELSEC-Q Structured Programming Manual

FXCPU Structured Programming Manual
[Device & Common]
2.9

Extension Register [R] and Extension File Register [ER]

FX /FX /FX
0S 0 0N
extension file registers.
Extension registers (R) are extended data registers (D).
The contents of extension registers (R) can be stored in extension file registers (ER). In FX
however, extension file registers (ER) are available only while a memory cassette is attached.
2.9.1

Numbers of extension registers and extension file registers

The tables below show the extension register (R) and extension file register (ER) numbers. (Numbers are
assigned in decimal.)
FX /FX
3U 3UC
PLCs
FX /FX
3G 3GC
PLCs
*1. Available only while a memory cassette is attached (because they are stored in the flash memory
inside a memory cassette).
*2. Can be changed to the latched (battery backed-up) type by parameter setting while an optional battery
is attached (, but the latched (battery backed-up) area cannot be set).
*3. Stored in the EEPROM built in the PLC, or stored in the EEPROM in a memory cassette while a
memory cassette is attached.
2.9.2

Data storage destination and access method

Because the memory for data storage is different between extension registers and extension file registers, the
access method is different as shown in the tables below:
Data storage destination
Device
Extension registers (R)
Extension file registers (ER)
Access method
Reading in program
Writing in program
Display module
Data change method
104
/FX /FX /FX /FX /FX
1S 1N 1NC U
Extension register (R)
(Latched (battery backed-up) type)
R0 to R32767
32768 points
Extension register (R)
(General type)
R0 to R23999
*2
24000 points
PLC
FX /FX
3U 3UC
FX 3G /FX 3GC
FX /FX
3U 3UC
FX
3G
FX
3GC
Access method
Test operation in online mode of GX Works2
Batch writing by GX Works2
Computer link function
2.9 Extension Register [R] and Extension File Register [ER]
/FX /FX /FX PLCs do not support extension registers and
2C 2N 2NC 3S
Data storage destination
Built-in RAM (backed up by battery)
Built-in RAM
Memory cassette (flash memory)
Built-in EEPROM or memory cassette (EEPROM)
Built-in EEPROM
Extension
registers
2 Devices in Detail
3U
Extension file register (ER)
(File type)
ER0 to ER32767
*1
32768 points
Extension file register (ER)
(File type)
ER0 to ER23999
*3
24000 points
Extension file registers
Only dedicated instructions can access.
Only dedicated instructions can access.
/FX PLCs,
3UC