1.1 Turning the System On and Off
1.1 Turning the System On and Off
The DPU has three switches that control power: the keyswitch, the power
selector, and the circuit breaker. Figure 2–1, Figure 2–2, and Figure 2–4 show
their locations. Chapter 2 provides details on these switches.
The DPU keyswitch inside the front door has three positions: OFF, ON, and
DIAGNOSTIC:
•
OFF turns DPU power off.
•
ON turns DPU power on.
•
DIAGNOSTIC is similar to ON, but it also enables the VMEbus RESET
button.
The DPU power selector switch has three positions: REMOTE, LOCAL, and
OVERRIDE:
•
REMOTE (lower position): Not used.
•
LOCAL (middle position): Turns on the DPU independently of the server.
•
OVERRIDE (straight up): Turns on the DPU, regardless of other conditions.
Warning
Do not use the OVERRIDE setting. It overrides critical safety
systems. The OVERRIDE setting is for factory use only.
Table 1–1 shows the relationships between the DPU keyswitch and the DPU
power selector.
Table 1–1 DPU Power Settings
DPU Power Selector
DPU Keyswitch
DPU Power
REMOTE
N/A
N/A
LOCAL
OFF
OFF
LOCAL
ON/DIAGNOSTIC
ON
OVERRIDE
Any setting
ON (Factory Use Only)
The power switch for the DECsystem 5900 server is on the front of the CPU
drawer. It is labeled
!
in Figure 1–4. The power switch for the DECstation 5000
server is at the rear of the CPU box. It is labeled
!
in Figure 1–5. Both are
rocker switches, labeled O and | . The server is ON when the | is pushed in.
1–4 System Overview
