Liebert Series 610 - Manual (Page 19)

Operation Description
15
Line Sync Signal
The Line Sync signal is sent between UPS systems when they are in parallel. Isolation amplifiers iso-
late the Line Sync signal levels between the two systems. The Line Sync signal synchronizes the UPS
systems to the Primary Bypass line. By maintaining sync with the Primary Bypass, uninterrupted
transfers to the Primary Bypass can be made, if a fault occurs while the systems are in parallel.
All status signals sent between the UPS system and the Tie Controls are isolated through optical cou-
plers. In addition, all these status signals have impedance protection between the signal wire connec-
tions and the system power supplies and ground.
The Tie Control’s power supply can use either UPS system’s output as its source and the Tie Control
power supply employs transformer isolation.
All necessary voltage sensing occurs at the tie cabinet and employs fuse, transformer and/or imped-
ance protection.