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5.10 Redundant CPU Functions Restricted in Redundant System
5.10.1 Enforced ON/OFF of external I/O
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(b) In the separate mode
1) Operation when control system is powered off and then on/control
system CPU module is reset and then its RESET switch is set to neutral
position
When the control system is powered off/the control system CPU module is
reset, the forced ON/OFF information is all cleared.
The input/output of which forced ON/OFF has been registered all return to the
status before the forced ON/OFF registration.
However, when the control system is powered off/the control system CPU
module is reset, the master station on the MELSECNET/H remote I/O network
changes to the sub master station. Therefore, the output to the remote I/O
station holds the status when the control system was powered off/the control
system CPU module was reset.
2) Operation when standby system is powered off and then on/standby
system CPU module is reset and then its RESET switch is set to neutral
position
If the standby system is powered off/the standby system CPU module is reset,
the forced ON/OFF information of the control system CPU module does not
change.
The input/output of which forced ON/OFF has been registered remains the
ON/OFF status according to the forced ON/OFF information of the control
system CPU module.
3) Turning power supply OFF or reset operation when the extension base
unit is connected
Do not turn OFF the power supply of the control system or perform reset
operation in the separate mode when the extension base unit is connected. (If
doing so, turn ON both systems simultaneously or cancel the reset.)
Table5.63 Operation When Control System Is Powered Off and Then On/Control System CPU Module Is Reset and Then its RESET
Switch Is Set to Neutral Position
Item
Module mounted on main base unit including Redundant CPU
Module mounted on remote I/O station
Input
Device X changes according to the external input.
[After power is switched on/RESET switch is set to neutral
position]
Device X changes according to the external input.
Output
The external output changes according to device Y.
[When power is switched off/CPU is reset]
The output status when the control system is powered off/
the control system CPU module is reset is held.
[After power is switched on/RESET switch is set to neutral
position]
The external output changes according to device Y.
Table5.64 Operation When Standby System Is Powered Off and Then On/Standby System CPU Module Is Reset and Then its RESET
Switch Is Set to Neutral Position
Item
Module mounted on main base unit including Redundant CPU
Module mounted on remote I/O station
Input
Device X remains ON/OFF according to the forced ON/OFF information.
Output
External output ON/OFF is continued according to the forced ON/OFF information.