AE design and install UPS's systems from single phase 120 or240VAC 1KVA to 3 phase 480 VAC 800KVA system with backup power generation diesel or turbine.

Before you start selecting a UPS for your control system takeinto consideration the following:

The PLC's or Controls are very fast in detecting input absences.Faster then your typical UPS which in most cases will have atransition time to switch from utility to battery that may onlylast 20ms. It is enough time for the PLC to sense the powerloss and shutdown your process. This is the worse casescenarios to have a typical UPS.

Another challenge on a 24/7 operation and zero down time ismaintenance. The UPS requires a battery check and otherperiodic tests. A typical UPS can not easily bypass themaintenance risking a potential shutdown.

The Best UPS for PLCs are the constant online ones, with staticand mechanical bypasses. By constant online we mean, it isalways working from the battery powered inverter. Thebatteries do not care what input or device supplies the power.You can have up to three different power sources or more. Forexample, two can be different utilities powers, another could bea generator. The UPS can be programed so in the event of apower loss on your utilities the UPS will send the signal to startthe generator and then the switch will occur. Therefore the PLCwill never sense the power loss. Depending on the size of theControls, the backup battery could range from 10 to 30minutes or more.

Worse case scenario Static switch is when the UPS is going intoa Fault and automatically switches into utility power or theTechnician needs to work on the UPS so the UPS will switch toutility by matching the form of the wave on the output orsynchronizing the output wave so there is no interruption. Thealarm(s) will be generated so the Operator knows the PLC orControl system are on Utility power. The technician couldeasily bypass completely the UPS system and isolate allincoming power to the UPS without any power loss.

Once the UPS is fixed or the maintenance is done the UPS hasa button which will turn on the static bypass.Then remove the mechanical bypass and go online. All of theseprocedures will occur without shutdown, the critical power.


Armani Consulting Corp