Omron CP1H-CPU - 05-2006 Operation Manual page 516

Replacing User-serviceable Parts
Low Battery Indications
Note
Note The minimum lifetime is the memory backup time at an ambient temperature
of 55 C. The typical lifetime is the memory backup time at an ambient temper-
ature of 25 C.
Memory Backup Time
5 yr
4 yr
3 yr
2 yr
1 yr
This graphic is for reference only.
The ERR/ALM indicator on the front of the CPU Unit will flash when the bat-
tery is nearly discharged.
ERR/ALM indicator
When the ERR/ALM indicator flashes, connect the CX-Programmer to the
peripheral port and read the error messages. If a low battery message
appears on the CX-Programmer (see note 1) and the Battery Error Flag
(A402.04) is ON (see note 1), first check whether the battery is properly con-
nected to the CPU Unit. If the battery is properly connected, replace the bat-
tery as soon as possible.
Once a low-battery error has been detected, it will take 5 days before the bat-
tery fails assuming that power has been supplied at lease once a day (see
note 2). Battery failure and the resulting loss of data in RAM can be delayed
by ensuring that the CPU Unit power is not turned OFF until the battery has
been replaced.
1. The PLC Setup must be set to detect a low-battery error (Detect Low Bat-
tery). If this setting has not been made, the BATT LOW error message will
not appear on the CX-Programmer and the Battery Error Flag (A402.04)
will not go ON when the battery fails.
2. The battery will discharge faster at higher temperatures, e.g., 4 days at
40 C and 2 days at 55 C.
CP1H CPU Unit
55 C
25 C 40 C
Section 10-2
Ambient temperature
485