Denso BHT-400B-CE - Manual (Page 58)

2.4 Replacement of the Backup Battery
If the following warning message appears on the LCD, you need to replace the backup battery (refer to
Section 2.4.1).
If you remove the backup battery, the contents of the memory may no longer be backed up so that the
data stored in the BHT may be lost. It is recommended that important data be saved into the FLASH
folder or uploaded to the host computer.
This warning message displays each time the power is turned ON after the backup battery discharge
count has reached 200 times or more.
Even if this warning message appears, you can continue operation by tapping the OK button in the top
right corner of the message window.
Each time the backup battery is fully discharged, the internal discharge counter automatically
increments by one; however, replacing the backup battery does not reset the counter to zero
automatically. You need to reset the discharge counter (refer to Section 2.4.2).
When the BHT is shipped from the factory, the discharge counter is reset to zero.
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