Mitsubishi Electric Melsec-Q172DCPU User Manual page 198

6 INSPECTION AND MAINTENANCE
POINT
(1) Do not use the battery exceeding its guaranteed life.
(2) When the battery hours (total power failure time) may exceed its guaranteed
value, take the following measure.
• Perform ROM operation to protect a program even if the battery dies at the
Multiple CPU system power-OFF.
• If SM51 turns on, the contents for programs, parameters, motion device(#),
latch range device and absolute position data cannot be guaranteed.
It is recommended to back-up the data periodically.
(3) When the total power failure time exceeds its guaranteed value, and SM51,
SM52, SM58 and SM59 turns on, immediately change the battery. Even if the
alarm has not yet occurred, it is recommended to replace the battery
periodically according to the operating condition
(4) The self-discharge influences the life of battery without the connection to
Q173D(S)CPU/Q172D(S)CPU/Q172DEX. The external battery should be
exchanged approximately every 4 or 5 years.
And, exchange the battery with a new one in 4 to 5 years even if a total power
failure time is guaranteed value or less.
(5) It is recommended to shift to the mode operated by ROM after the programs
and parameters are fixed. The erasing of the programs and parameters can be
avoided even if the battery decrease. (The ROM writing cannot be executed
for the current position of the servo motor in the absolute position system,
home position and latch device. Back up them beforehand using
MT Developer2.)
Refer to Section 4.4 of the "Q173D(S)CPU/Q172D(S)CPU Motion controller
Programming Manual (COMMON)" for details of the ROM operation.
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