Allen-Bradley ControlNet PLC-5, Руководство пользователя

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Backup States B-5
Secondary Backup State
When a PLC-5 ControlNet backup system is in Run mode, and is not
actively controlling the system outputs, it is in the Secondary backup
state. The Secondary LED is solid yellow, the Primary LED is off,
and the Qualified LED is solid green. The PLC-5 can go out of
Secondary backup state if either the PLC-5 system goes out of Run
mode, or the partner PLC-5 system is no longer the primary. If the
partner PLC-5 is no longer the primary, the PLC-5 in the Secondary
backup state becomes the primary and assumes control of the system
outputs.
When the PLC-5 is in the Secondary backup state, you cannot make
any backup configuration changes to that PLC-5 system. All backup
configuration changes must be made to the primary system and those
changes are immediately passed on to the secondary system.
Backup State Transitions
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Qualification
Qualification occurs when the PLC-5 ControlNet backup system
transitions from the No Control backup state to either the Secondary
backup state or the Primary backup state. You activate this backup
state transition by changing the PLC-5 system from Program mode to
Run mode.
You can tell that a qualification is active when the Qualified LED
blinks yellow and green, alternately.
Qualification: From the No Control State to the Primary State
The backup state transition from No Control backup state to the
Primary backup state occurs when the PLC-5 system transitions from
Program mode to Run mode and
• there is no partner PLC-5 system, OR
• the partner PLC-5 system is not in Primary backup state, OR
• the partner PLC-5 system is not communicating with this PLC-5
processor
The transition from No Control backup state to Primary backup state
is simple. There are no checks to be done. The transition occurs
immediately if there is no Qualification Connection Delay. Once the
transition to the Primary Backup State is complete, the LED's on the
1785-CHBM cartridge indicate the new backup state.