■Operations
Power on CPU Switch Unit first. The power switch of this unit is located underneath the front panel. Remove the front panel by removing the 4 screws on the panel.
The CPU Switch Unit has a default setting: the A CPU is the active CPU.
After powering on this unit, the "A" button will be on and the "B" button will be off automatically. It will also light the "AUTO" button to indicate that the auto- switching mode is selected.
Secondly, power on A CPU and B CPU. While the CPUs are booting, the diagnostic indicators on the front panel will be turned on. At this moment, A CPU is selected as the active CPU and B CPU is held at the standby mode.
If an error occurs in A CPU, the diagnostic indica- tors will turn off and A CPU will be reset. Then the "A" button will be off.
On the other hand, the CPU Switch Unit will switch, the B CPU as the active CPU.
The "B" button will be on and the "AUTO" button will be blinking. This blinking means that a CPU switch has occurred in the past days.
In the blinking mode, even if B CPU is corrupted and A CPU is good condition, this unit will judge to switch the active CPU from B CPU to A CPU. After checking the reason of the CPU switch and remove problems, please change the flashing mode to nor- mal automatic mode by pressing the "AUTO" button. The manner of changing B to A is same as A to B.
Also this unit can be operated manually. Pull up the protection cover of the "AUTO" button and press "AUTO", it’s LED will go off and it will change to manual mode. In manual mode, it is possible to select the active CPU manually by pressing the "A" button or "B" button. Also it is easy to change to the automatic mode by pressing the "AUTO" button in the LED on status.
Finally this unit has individual reset buttons for each CPU. By pressing the "A RESET" button, you can reset the A CPU, and by pressing "B RESET" button you can reset B CPU.
The "AUTO", "A", "B", "A RESET" and "B RESET" but- tons are protected with a
