MU-T Series UPS Introduction 

The UPS consists of a battery charger, a large battery, and a chopper to convert the battery’s dc power into quality ac power. The UPS is always on and is always supplying power to its load through the battery that is on a float charge. Should the ac input fail, the UPS continues to serve the load without any changes and it will continue to operate until the battery is discharged, or the ac input to the UPS charger is restored. The capacity of the battery pack is specified by the UPS manufacturer and will provide many hours of backup.

UPS transfer switches 

The UPS usually has two transfer switches. A switch on the output of the UPS automatically transfers the loads to plant power in case of failure in the UPS. A second transfer switch to the UPS input charger allows manual transfer to public utility power if there is extended failure of plant power. A UPS with two ac sources provides the means for several backup strategies. The HPM offers additional permutations with its optional redundant Power Supply Modules, dual-feeds, and battery backup. The need for all of this backup redundancy depends on how important it is to have a working control system when plant power is out for an extended period.

FTA 

Terminal connectors on the Field Termination Assembly (FTA) provide the connection points for the process control wiring. Fuses, relays, and resistors protect the FTA circuitry, and sense, condition, or operate the connected device. The FTA communicates with an associated IOP, which in turn communicates with the HPMM(s) through the I/O Link Interface.

FTAs types

Standard types of FTAs, as described, interface the field wiring and provide communication with an associated IOP. They are categorized as “standard” because Galvanically Isolated FTAs are also available as described.