Testing Switchover of a Quantum Hot Standby System
Original instructions
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Testing Methods (First Time)
Follow these steps to conduct tests to observe:
These tests are not necessary but helpful. If your racks are horizontally parallel and within 1 meter (3 feet) apart, the transfer process is easier to observe.
Hot Standby Start-up and Application Program Transfer
Follow these steps for start-up and application program transfer:
Step
Action
1
Configure two racks with identical hardware and firmware.
2
Connect to a Remote I/O (RIO) drop.
NOTE: Ensure that the fiber optic sync-link cable is connected between the controllers.
3
Start Control Expert software and configure the local rack and the Remote I/O drop for your physical configuration.
4
Execute the Build Project command and save your application program.
5
Power up and connect Control Expert to one controller.
NOTE: The front panel keypad displays No Conf.
6
Download your application program and put the controller in the RUN mode.
NOTE: The controller becomes the RUN Primary CPU.
7
Power up the other controller.
NOTE: Application Program Transfer occurs automatically. The other controller becomes the RUN Standby CPU.
8
Ensure the Primary CPU and Standby CPU controllers are in RUN Primary CPU and RUN Standby CPU mode.
Preparing to Switchover
After completing the Hot Standby Start-up and Application Program Transfer procedure, your Quantum Hot Standby system is ready to perform a Switchover. Perform the Switchover using either:
NOTE: To observe a Switchover effect on the I/O modules, configure the Remote I/O (RIO) drop with a discrete output module during your initial start-up. Before performing a Switchover, connect to the Primary CPU and force the output bits in the module. Perform the Switchover and take note of the bumpless Switchover effect on the forced bits.
Switchover Test Using Front Panel Keypad
To force a Switchover using the front panel keypad, do the following:
Step
Action
1
Access the front panel keypad of the Primary CPU controller.
2
Go to PLC Operation → Hot Standby → Hot Standby Mode
3
Change Run to Offline.
NOTE: Ensure that the Standby CPU switches to Primary CPU.
4
Change Offline to Run.
NOTE: Ensure that the LCD displays Run Standby CPU.
Switchover Test Using Command Register
Follow these steps.
Step
Action
1
Connect Control Expert to the Primary CPU.
2
Observe if the controller order on the Primary CPU is A or B using either of the following methods:
  • Control Expert status dialog:
    Refer to the bottom of the Control Expert window when connected online.
  • Access the Command Register system bits:
    • If the connected Primary CPU is A, set.%SW60.1 to 0.
    • If the connected Primary CPU is B, set.%SW60.2 to 0.
NOTE: Ensure that the Standby CPU switched to Primary CPU
If bits %SW60.1 and %SW60.2 are set to 0 simultaneously, a switchover occurs:
  • Primary PLC goes to RUN Offline
  • Standby PLC goes to RUN Primary
3
Connect Control Expert to the new Primary CPU.
4
Access the Command Register system bits as in Step 2 and set them ti 1.
NOTE: Ensure Standby CPU displays RUN Standby CPU.
NOTE: Ensure the Primary CPU and Standby CPU controllers are in RUN Primary CPU and RUN Standby CPU mode.
Warm Start Restarting recommendation
After a global power loss while the system is running, the two CPUs synchronize each other at power up (primary PLC selection).
To ensure synchronization at power recovery, two methods are proposed: