Vertiv Liebert STS2 - Transfer

Vertiv™ | Liebert® STS2/PDU
™
User Manual | Rev. 6 | 10/2017 70
8.2.2 Transfer
Should the preferred source fail or be outside acceptable voltage limits, the Liebert STS2/PDU transfers the
input to the alternate source until the problem is rectified in the preferred source. The unit can be set to
automatically transfer the input back to the preferred source or allow the transfer to be done only manually.
8.2.3 Transfer Inhibit
For a transfer to be completed between input sources, the sources must meet certain parameters or the transfer
cannot take place. Uninterrupted transfer between sources is inhibited due to input source failure, sources out of
sync, switch failure or the unit is in bypass mode.
8.2.4 Bypass
The Liebert STS2/PDU can be manually bypassed to allow the power from a source to directly flow to the output
load. This bypass allows the unit’s electronics to be serviced without dangerous voltages being present.
The Liebert STS2/PDU includes key-interlocked maintenance bypass breakers that allow either input source’s
electronics to be bypassed for maintenance without interruption of power to the load. The maintenance bypass
allows all electronics to be isolated from the input, output and bypass connections. Bypass instructions are
available from the touchscreen and are discussed later in this manual.
8.3 Operator Controls
The Liebert STS2/PDU is equipped with an interface to configure and monitor the unit either locally or remotely.
The Color Graphical Display is a touchscreen LCD that provides a color diagram (Mimic) that displays the
current status of the unit. System parameters are displayed and help is available to define events. See Figure 57
below and Figure 56 in 7.0 - Installation Drawings. The touchscreen menus allow the operator to initiate source
transfers, view event and history logs and view bypass and other operational instructions.
Figure 57 Liebert STS2/PDU touchscreen
Touchscreen control buttons allow you to reset alarms, silence the audible alarm, review configurations, event
and history logs, preferred source, startup and bypass procedures and the help menu.
Qualified personnel, with a password, can use these menus to configure parameters, select a preferred source
and do manual source transfers.
Units can be accessed from a terminal or a PC running terminal emulation software attached to the unit.
Through the RS-232 access, you can monitor and configure the unit, plus remotely select a preferred source. See
12.1 - Using the RS-232 Port for instructions on using the RS-232 interface.
Mimic
Event display
Event controls
Display panel
and help screen
Menu options