Lamp Test/Reset Push Button; Audio Reset Push Button; Digital Load Bus Sync; System Description - Vertiv Liebert EXL Operation And Maintenance Manual

4.3.1

Lamp Test/Reset Push Button

The Lamp Test/Reset push button is used to verify that each LED indicator is in working condition and to reset
an LED indicator that has been triggered by a condition at the load or UPS.
To test the LEDs, press the Lamp Test/Reset push button. This lights all of the LED indicators for visual
inspection.
If an LED indicator does not respond to the lamp test, contact your local Vertiv
To reset an activated LED, press the Lamp Test/Reset push button.
4.3.2

Audio Reset Push Button

The Audio Reset push button is used to silence an audible alarm that has been triggered and reset the alarm to
activate on the next alarm condition. After correcting the alarm condition, press the push button to reset the
audible alarm.
4.4 D L B
IGITAL OAD
4.4.1

System Description

Liebert's Load Bus Sync (LBS) option keeps the output of two or more independent Uninterruptible Power
™
Systems in synchronization, even when the systems are operating from different power sources. The Liebert LBS
works by synchronizing the Designates Slave System (DSS) to the output of the Designated Master System
(DMS). There are no other connections between the logic or controls of either UPS. This ensures maximum
system independence and reliability.

4.4.2 LBS Configurations

• Load Bus Sync—Enable or Disabled (default: Disable)
• LBS Master Select—Master or Slave (default: Slave)
NOTE
The LBS settings permit proper operation with only one UPS set as the Master unit.
• LBS Slave Priority – 0 to 7 (default: 0)
NOTE
Setting of '0' will disable LBS Slave Priority
4.4.3

Normal Operations

The LBS will synchronize the Designated Slave Systems (DSS) to the Designated Master System (DMS). The
DSS will synchronize to the DMS output if the DMS is in Normal, Battery, Bypass or Maintenance Bypass Mode.
If the DSS transfers to Bypass Mode or Maintenance Bypass mode, the DMS will synchronize to the output bus of
the DSS. This re-selection of master will occur automatically.

4.4.4 Slave Priority

When Slave Priority is enabled, the LBS system will work the same as Normal operations (See 4.4.2 -LBS
Configurations except when the DMS disqualifies it bypass source. If the DMS's bypass is disqualified, the LBS
system will synchronize to the output of the DSS with the lowest Slave Priority number that has a qualified
bypass. The LBS system will synchronize back to the DMS when the DMS's bypass is qualified or all DSS's
bypass are disqualified.
If a DSS LBS Slave Priority is set to 0, it will not assume the synchronization of the system if the DMS disqualifies
its bypass.
™
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| Rev. 8 | 02/17 44