KEYENCE Visual KV Series - Manual (Page 31)

Chapter 1 Configuration and Specifications 1-7
1
1
Visual KV
Series
Data backup function against instantaneous power interruption
■ Electrical double-layer capacitor built into the basic unit
Contents of data memories, current values of counters, and the contents of internal
utility relays in a Visual KV Series basic unit are saved in RAM backed up with an
electrical double-layer capacitor built into the Visual KV Series basic unit by the Data
backup function against instantaneous power interruption.
The backup time varies depending on the ambient temperature.
If power to the Visual KV Series basic unit remains OFF for more than the holding
time by the RAM, the data may be cleared or become corrupted.
To avoid the data being cleared, save the data in the EEPROM using the backup
function to the EEPROM.
➮ For writing to and reading from the EEPROM, refer to "LOAD mode and SAVE mode" (p.1-96).
When a user program is written, it is saved in RAM. The next time the power is
turned on, the user program is automatically transferred from RAM to the EEPROM
and is also saved in the EEPROM. If power to the Visual KV Series basic unit will
remain OFF for more than the backup time by the RAM, turn the power off immedi-
ately after writing a user program, and then turn the power on again so that the user
program is transferred to the EEPROM.
• Data backup function by electrical double-layer capacitor built into the
basic unit
Visual KV Series: 2 months or more at 25°C (77°F)
(20 days or more at 25°C (77°F) in KV-10xx)
■ EEPROM
The Visual KV Series basic unit is equipped with a backup function to save pro-
grams, contents of data memories, current values of counters, etc. in the EEPROM.
Even if the power is interrupted or power to the Visual KV Series basic unit remains
OFF, the data is still saved. When the power turns ON again, the contents of the
EEPROM is automatically read. (The contents of data memories and current values
of counters should be read by manipulating the Access Window.)
When data is changed and the power is turned off without saving the changed data,
the changes are saved only in the built-in electrical double-layer capacitor and are
not saved in the EEPROM.
If the Visual KV Series basic unit remains OFF for 2 months or more at 25°C (77°F)
(20 days or more at 25°C (77°F) in KV-10xx) while the data is backed up only with
the built-in electrical double-layer capacitor, the saved contents may be cleared or
become corrupted.
If the Visual KV Series basic unit will remain OFF for a long period of time, save the
data in the EEPROM.
➮ Refer to "LOAD mode and SAVE mode" (p.1-96).
• Data backup function with the EEPROM
Visual KV Series: 10 years or more at 25°C (77°F)
(available number of overwrites: 100,000 times or more)
1.2 Specifications
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