User`s manual

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6 INSPECTION AND MAINTENANCE
6.5 External Battery
The battery installed in the Motion CPU module is used for data retention during the
power failure of the program memory and latch device. Special relays SM51 or SM58
turn on due to the decrease of battery voltage. Even if the special relays turn on, the
program and retained data are not erased immediately.
However, if these relays are overlooked, the contents may be erased.
After relay SM51 or SM58 turns on, replace the battery quickly within the data
retention time for power failure (3 minutes).
POINT
(1) SM51 or SM58 turns on when the battery voltage falls below the specified
value, and remains ON even after the voltage is recovered to the normal
value. SM51 or SM58 turns off by power supply on again or reset.
(2) After SM51 or SM52 turns on, replace the battery quickly.
• SM51 turns on at the battery voltage 2.5V or less.
• SM58 turns on at the battery voltage 2.7V or less.
(3) If SM51 turns on, the details of the programs, parameters and absolute
position data cannot be guaranteed.
It is recommended to back-up the battery periodically.