Emerson Static Transfer Switch user manual Operator Controls, Bypass

Introduction to Liebert STS2 Operations

8.2.4Bypass

The static transfer switch 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 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 connec- tions. Bypass instructions are available from the touch screen and are discussed later in this manual.

8.3Operator Controls

The Liebert STS2 is equipped with an interface to configure and monitor the unit either locally or remotely. The Color Graphical Display is a touch screen 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 44 below and Figure 30. The touch screen menus allow the operator to ini- tiate source transfers, view event and history logs, and view bypass and other operational instruc- tions.

Figure 44 Liebert STS2 touch screen display

Mimic

Event controls	Display Panel
	and
Event Display	Help Screen

Menu Options

Touch screen control buttons allow you to reset alarms, silence the audible alarm, review configura- tions, 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 pre- ferred source and do manual source transfers.

LED display units do not have the color LCD touch screen. Instead of the touch screen, these units are monitored by a series of LEDs and controlled by a series of push buttons.

Both units can be accessed from a terminal, or a PC running terminal emulation software, that is 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 on page 76 for instructions on using the RS-232 interface.

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