Omron SYSMAC C200H Installation Manual page 34

Memory Units
RAM Unit
Caution
!
Switches on Memory Units
24
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Data can be randomly written to and read from the RAM Unit. However, the Unit
requires battery or capacitor back-up in order to retain the information when the
power is OFF. Units with battery back-up can retain their data for approximately
five years at room temperature (25°C). Units with capacitor back-up retain their
data for approximately 20 days at room temperature, but the length of time va-
ries with temperature as shown below.
Capacitor
back-up time
(days)
Be sure to turn off the power when mounting or dismounting a Memory Unit, or
an error will result and the internal circuitry may be damaged.
Note A memory error might occur when a RAM Unit is installed in a C200H-
CPU21-E/23-E/31-E CPU Unit with data written using a C200H-
CPU01-E/03-E/11-E CPU Unit or a GPC and C500-PRW06 PROM Writer. Turn
the PC power off and on again to clear the error.
Two switches are provided on Memory Units, as shown below.
1
2
SW1 (the write-enable switch) only has an effect if the Unit is a RAM Unit or EE-
PROM Unit. Peripheral devices can only write data to these Memory Units if
SW1 is ON. When you wish to write data to this Memory Unit, make sure SW1 is
set to the ON position. After you have finished writing the data to the Memory
Unit, turn SW1 to the OFF position so that the data will be protected from any
further changes. If you try to write data to the Memory Unit while SW1 is in the
OFF position, the message "DISABLED ROM" will appear on the Programming
Console.
SW2 Selects what operating mode the PC will be in when power is applied to the
System. If there is no peripheral device connected to the CPU Unit, the PC will
enter RUN mode when power is applied. If a Programming Console is con-
nected to the CPU Unit, the PC will enter the mode that the Programming Con-
sole is set to. If a peripheral device other than the Programming Console is con-
nected to the CPU Unit, the PC will enter the mode specified by SW2.
20
10
7
1
25
Ambient temperature (°C)
Write-enable switch
(SW1)
ON OFF
Initial mode selector
(SW2)
Section 2-6
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