Structures Of Extension Registers And Extension File Registers; Initialization Of Extension Registers And Extension File Registers - Mitsubishi Electric MELSEC FX3U Programming Manual

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition

4.10.3 Structures of extension registers and extension file registers

One extension register consists of 16 bits. Extension registers can be used in 16-bit and 32-bit applied
instructions in the same way as data registers.
1) 16-bit type
One extension register (consisting of 16 bits) can handle a numeric ranging from −32768 to +32767.
High
order
0
b15
Sign
0: Positive
number
1: Negative
number
A numeric value is usually read from and written to an extension register by applied instructions.
However, a numeric value can also be directly read from and written to an extension register from a
display unit, display module, or programming tool.
2) 32-bit type
Two serial extension registers (consisting of 32 bits) can express a 32-bit numeric value ranging from
−2,147,483,648 to +2,147,483,647. (A larger number register handles high-order 16 bits, and a smaller
number register handles low-order 16 bits.)
High
order
0
b31
Sign
0: Positive
number
1: Negative
number
• In the case of 32 bit type, when an extension register on the low-order side (example: R0) is specified, the
subsequent serial number on the high-order side (example: R1) is automatically occupied.
Either an odd or even device number can be specified for the low-order side, but it is recommended to
specify an even device number for the convenience of the monitoring function for display units, display
modules, and programming tools.

4.10.4 Initialization of extension registers and extension file registers

The contents of extension registers are backed up by the battery even when the power is turned OFF or when
the PLC mode switches from STOP to RUN in FX
changed to the latched (battery backed) type and the optional battery is installed.
When initializing the contents of extension registers, clear them using a sequence program or GX Developer.
1. When clearing the data using a program
• When initializing some extension registers (R)
Example: When initializing (clearing) R0 to R199
Command
• When initializing extension registers and extension file registers in sector units
(Sectors are not provided for extension registers and extension file registers in FX
Example: When initializing R0 to R4095 and ER0 to ER4095 (initializing two sectors starting from R0 and
ER0)
Ex. FX /FX
3U
Command
2. When clearing the data using GX Developer
Select [Online] → [Clear PLC memory...] in GX Developer, and clear [Data device].
This operation initializes the contents of timers, counters, data registers, file registers and extension registers.
140
R0, ER0 (16 bits)
1 0 1 0 1 0 1 0 1 0 1
R1, ER1 (high-order 16 bits)
1 0 1 0 1 0 1 0 1 0
FNC 16
K0
FMOVP
PLCs
3UC
FNC 292
R0
INITRP
4.10 Extension Register [R] and Extension File Register [ER]
Low
order
0 1 0 1
b0
R0, ER0 (low-order 16 bits)
1 0 1 0 1 1 1 1 1 0 0
/FX PLCs and in FX
3U 3UC
R0 K200
The current value in Ro to R4095 is initialized
K2
to "FFFF ".
H
4 Devices in Detail
0 0 1 1 1 1 0 0 0 0
PLCs if extension registers are
3G
PLCs.)
3G
Low
order
b0