Alpha Technologies FXM350_Micro350 UPS - Manual (Page 61)

59 017-241-B0 Rev B
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 activated and begins to count down from a user defined value. When the timer reaches zero, the pro-
grammed 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 41 — 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 pow-
er 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
running 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 42 — Time Of Day Action Operation