10MAINTENANCE AND INSPECTION
10.3 Battery Replacement
When the voltage of the program and power interrupt
Even if these special relays are energized, the contents of the program and power interrupt
If the energization of these relays is recognized, however, these contents may be deleted unintentionally.
While a total of the power interrupt
POINTS
The SM51 is used to give an alarm when the capacity of the battery is lowered. Even after it is energized, the data is held for a specified time.
For safety, however, replace the battery with a new one as early as possible. The SM52 is energized when the battery causes a complete discharge error. Immediately after the relay has been energized, replace the battery with a new one.
Whichever voltage of the battery of the CPU module and SRAM card is lowered, the SM51 and SM52 are energized.
To identify the specific battery of the memory of which voltage is lowered, check the contents of the special resisters SD51 and SD52.
When the voltage of the battery of each memory is lowered, the bit corresponding to each of SD51 and SD52 memories is turned on.
Bit No. of SD51 and SD52 | Object |
Bit 0 | CPU module |
Bit 1, 2 | SRAM card |
POINTS
The relation between the backups of the memories preformed by the batteries which are installed on the CPU module and SRAM card is described below. The items that must be considered are the following two points.
1)The battery installed on the CPU module cannot backup the memory of the SRAM card.
2)The battery installed on the SRAM card cannot backup the memory of the CPU module.
Power supply | Battery of CPU | Battery of | Memory of CPU | Memory of |
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Module | Module | SRAM Card | Module | SRAM Card |
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| Connection | ON |
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ON | OFF |
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Unconnection | ON |
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| OFF |
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| Connection | ON |
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OFF | OFF |
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Unconnection | ON |
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| OFF |
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| : Backup enable | : Backup unable |
The standard service life and replacement procedures of the battery is described on the next page.
10 - 4 | 10 - 4 |