Alpha Technologies FXM 650, 1100, 2000 UPS - Manual (Page 44)

017-230-B4 Rev B 42
Programmable Dry Contact Time of Day Action
You can assign a dedicated timer to a dry contact. Upon entering the Inverter operating mode, the timer is acti-
vated and begins to count down from a user defined value. When the timer reaches zero, the programmed dry
contact relay is activated (Status = ON).
 Inverter
mode
entered
 Dry contact
activates when timer
counts down to zero
 Timer
starts to
count down
Microprocessor
Figure 26 — Programmable Timer Operation
An example of a typical application of this timer-controlled dry contact function is control of a traffic light. When
the grid power fails, the Alpha FXM goes into the Inverter mode and continues supplying backup power to the
traffic light. Since the batteries supplying the backup power have limited capacity, a timer controlled dry contact
is usually configured to switch the traffic light into the flashing amber or flashing red mode after a user-defined
period to conserve battery power.
This setup works for non-rush hour traffic, but during rush hour, it may be desirable to keep the traffic light run-
ning normally as long as backup power is available. To address this issue, a new feature called the Time of Day
Action has been added to deactivate the timer during a user defined time period up to twice each day.
 Inverter
mode
entered
 Dry contact activates
when enabled timer
counts down to zero
 Timer starts to
count down
if enabled
Microprocessor
Real time clock
Peak period
settings
Disable Timer (Action=ON) or
Enable Timer (Action=OFF)
Figure 27 — Time Of Day Action Operation