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FX3G/FX3U/FX3UC Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
37 Operation of Special Devices (M8000 -, D8000 -)
37.2 Supplement of Special Devices (M8000 - and D8000 -)
31
FNC275-FNC279
Data
Transfer 3
32
FNC280-FNC289
High Speed
Processing 2
33
FNC290-FNC299
Extension File
Register
34
FNC300-FNC305
FX
3U
-CF-ADP
35
SFC•STL
Programming
36
Interrupt
Function
37
Special Device
38
Error Code
A
Version Up
Information
B
Execution Times
37.2.10 Battery [BATT (BAT)] LED and [ALM] LED OFF command [M8030]
When M8030 is set to ON, the battery LED does not turn ON even if the voltage in the battery for memory backup
becomes low.
When the indication of "battery voltage low error" is not required or when the battery is removed, set M8030 to ON.
When batteryless operation is required in FX
3U/FX3UC PLCs, do not use M8030 and refer to "1. Batteryless operation
by parameter setting in peripheral equipment" below.
1. Batteryless operation by parameter setting in peripheral equipment
Specify "batteryless operation" mode in the parameter settings.
1) When the batteryless operation option is specified
When "batteryless mode" is specified, the control to turn OFF the BATT (BAT) LED and initialization of the latch
area for the devices shown below are automatically executed by the PLC system.
- Auxiliary relay (M) - Counter (C) - State relay (S)
- Data register (D) - Timer (T) - Extension register (R)
2) Applicable programming tool
Some programming tool versions do not support "batteryless mode." In such versions, input a sequence program
to enable the batteryless operation as explained below.
2. Conditions for batteryless operation
1) An FLROM (optional memory cassette) for program memory is installed so that programs are not erased. (only in
FX
3U/FX3UC PLCs)
2) The latch (battery backed) devices such as auxiliary relays and data registers are not used for control.
3) The sampling trace function is not used.
4) The real time clock function is not used. (only in FX
3U/FX3UC PLCs)
3. Example program for batteryless mode
When a parameter setting for "batteryless mode" is not available, create the sequence program shown below.
• Example program for clearing the memory backup area
{when the latch (battery backed) ranges in the parameter settings are set to their initial values.}
*1. The device number is the default number of the latch (battery backed) device range limits in the parameter
settings.
If the latch (battery backed) device numbers in the parameter settings are changed to other values, change
the device numbers here in accordance with the changed latch ranges.
4. Cautions for communication setting devices (D8120, D8121 and D8129)
Special data registers D8120 (communication format), D8121 (station number setting) and D8129 (timeout check
time) are backed up by the battery in FX
3U/FX3UC PLCs.
When performing the batteryless operation in FX
3U/FX3UC PLCs, reset these special data registers using the
procedure described above, and then transfer proper set values to them using a program.
The communication conditions can be set in the parameter settings.
When the communication conditions are set in the parameter settings, the PLC transfers the parameter values to the
above special data registers before operation. Thus it is recommended to set the communication conditions via the
parameter settings.
M8000
RUN monitor
FNC 40
ZRST
M500
*1
M7679
M8002
Initial pulse
Auxiliary relay
S500
*1
S4095
State relay
T246 T255
Timer
C100
*1
C199
*1
C220
*1
C255
*1
32 bit counter
D200
*1
D7999
Data register
M8030
BATT(BAT) LED turns OFF.
16 bit counter
FNC 40
ZRST
FNC 40
ZRST
FNC 40
ZRST
FNC 40
ZRST
FNC 40
ZRST
R0 R32767
FNC 40
ZRST
or
M8000
RUN monitor
M8002
Initial pulse
M8030
BATT(BAT) LED
turns OFF.
M8032
The latch areas
are cleared.