Battery Change Frequency - Mitsubishi MELSEC-A A1SD71-S2 User Manual

9.
MAINTENANCE
MELSfGA
9.2
Battery Change
9.2.1
Battery
change
frequency
When the data backup battery voltage drops, the LED on the AiSD71 front
panel is lit and an input signal (battery error) to the PC CPU is enabled. The
battery is live for about one month more and,
if
it is not replaced, data will then
be lost or corrupted.
Guide for preventive maintenance
1)
The battery should be replaced every 4 to
5
years
if it
is only used for
memory back up for a maximum of 300 days in that period.
2) Battery changing frequency for memory backup duty exceeding 300 days
1
j
Assume that there are five operation days (1 0-hour operation and 14-
1
hour power-off during a day) and two power-off days
in a week. Under
!
these conditions, power-off period during one week is:
1
I
I
I
I
I
I
I
I
I
14 (hours) x
5
(days) = 70 hours
I
24 (hours)
x
2 (days)
=
48 hours
I I
7200
(hours) / (70
+
48) (hours)
=
61
(weeks)
,
I
I
61 (weeks)
x
7 (days)
=
427 (days)
I
I
:
Regarding one month as 30 days,
I
I
I
4
I
I
, 427 (days) /
30
(days)
=
14.2 months
j
Hence,
I
I
I
it
is necessary to chanae the battery every 14 mdnths.
I
I
I
I
I
I
I
The same battery is used for all MELSEC-A series modules.
The battery can be stored for five years. The battery is guaranteed to work for 300 days in total.
The following battery is used. When replacing the battery, order from a Mitsubishi representa-
tive.
Product : Lithium battery
Model
:
A6BAT (with 3.6 V lead wire)
Precautions when handling the battery
(1)
Do
not short circuit the battery.
(2)
Do
not take the battery apart.
(3) Keep the battery away from fire.
(4) Do not heat the battery.
(5)
Do
not solder the electric poles.
(6) Do not measure the voltage using a tester. Otherwise, the capacity will be greatly lowered.
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