4. HOW TO USE
17
4.3
Turning the Power On
The LT 4448 power supplies are redundant. When both power supplies are turned on,
operation continues uninterrupted even if one of the power supplies fails.
Connect the power cords to AC INPUT 1 and AC INPUT 2. When the power turns on, the
POWER 1 and POWER 2 indicators on the front panel light in green.
The LT 4448 uses a relay. A clicking noise can be heard when you turn the power ON or OFF,
but this is not a sign that the instrument is malfunctioning.
● Standby
When you turn the power ON, the LT 4448 enters Standby mode. When on standby, the
SYNC SOURCE PRIMARY, AUTO SWITCHING SWITCH FAULT, CONTROL LOCAL, and
KEY LOCK ON and OFF LEDs light, and the AUTO SWITCHING DISABLED LED blinks.
The LT 4448 does not function when it is in this state.
Figure 4-2 Standby mode
● Leaving Standby Mode
The LT 4448 has a last-memory feature. When the standby state ends, the LT 4448 is set to
the conditions that it was in when the power was turned off the last time.
● Setting the Standby Time
You can use a DIP switch or Web browser to set the standby time. Select a setting that is
appropriate for the rise time of the system signal source that you are connected to.
The factory default setting is approximately 2 minute.
Reference
4.5.7, “Setting the Operation Mode and Standby Time”
4.4
Turning the Power Off
Remove the power cords from AC INPUT 1 and AC INPUT 2.
When you turn off the power, the output signals of channels 1 to 11 and LTC are set to
PRIMARY.