Types Of Backup Methods Against Power Failure - Mitsubishi Electric MELSEC FX3U Programming Manual

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
2.6.3

Types of backup methods against power failure

There are following types of latch (battery backup) for the program memory and built-in devices in the PLC.
1. Battery backup method
a) FX /FX
3U 3UC
Item
Latched (battery
backed) contents
Maintenance
Cautions
b) FX PLCs
3G
Item
Latched (battery
backed) contents
Maintenance
Cautions
2. Memory cassette backup method
a) FX /FX
3U 3UC
Item
Latched (battery
backed) contents
Maintenance
Cautions
b) FX PLCs
3G
Item
Latched (battery
backed) contents
Maintenance
Cautions
3. EEPROM memory (built in PLC) backup method
a) FX PLCs
3G
Item
Latched (battery
backed) contents
Maintenance
Cautions
PLC
The battery backs up the RAM memory built in the PLC, latched (battery backed) type devices and
clock data.
The battery life is around 5 years, (when the ambient temperature is 25°C).
For replacement information, refer to the Users Manual [Hardware Edition] of each PLC.
1) When the battery voltage becomes low, sequence programs and other latched (battery backed)
contents are lost.
2) When an optional memory cassette (flash memory) is mounted, it is not necessary to back up
sequence programs by the battery.
The optional battery backs up the RAM memory built in the PLC and clock data.
The battery life is around 5 years, (when the ambient temperature is 25°C).
For replacement information, refer to the Users Manual [Hardware Edition] of each PLC.
When the optional battery voltage becomes low, the RAM memory built in the PLC and clock data are
lost.
PLC
1) The flash memory built into the memory cassette backs up sequence programs.
2) A battery is required to back up latched (battery backed) devices and clock data from failure.
Maintenance is not necessary.
The upper limit is set to the number of times for overwriting.
(Refer to the Hardware Edition of the main unit.)
The EEPROM memory built in the memory cassette backs up sequence programs.
Maintenance is not necessary.
The upper limit is set to the number of times for overwriting.
(Refer to the Hardware Edition of the main unit.)
The EEPROM memory built in the PLC backs up latched (battery backed) type devices and sequence
programs.
Maintenance is not necessary.
The upper limit is set to the number of times for overwriting.
(Refer to the Hardware Edition of the main unit.)
2 Overview (Sequence Program)
2.6 Program Memory and Devices
Description
Description
Description
Description
Description
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