Mitsubishi 00JCPU User Manual page 190

(8) Precautions
(a) When a local device or initial device value is specified
Device data cannot be latched even if the device has been latch-specified.
(b) Use of battery
Device data in the latch range are held with the battery installed to the CPU module.
• Even for the boot operation, the battery is required to latch device data.
• Note that if the battery connector is disconnected from the connector of the CPU module while the power
supply for the programmable controller is off, device data in the latch range will not be held and will
become undefined.
(c) When the start mode is set to the hot-mode in the Redundant CPU
Device data outside the latch range are held as well. (Except some devices, such as the step relay and the
index register.)
To clear these data, perform latch clear operation. (
6 - 10
Section 3.7(2)(b))