Dry contact
activates when timer
counts down to zero
Timer
starts to
count down
Inverter
mode
entered
Microprocessor
Dry contact activates
when enabled timer
counts down to zero
Timer starts to
count down
if enabled
Inverter
mode
entered
Real time clock
Disable Timer (Action=ON) or
Enable Timer (Action=OFF)
Peak period
settings
Microprocessor
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 programmed
dry contact relay is activated (Status = ON).
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 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
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.
Figure 42
— Time Of Day Action Operation
Page
59
to
106
Summary of Contents for FXM 350 Series
Page 1: ...Alpha FXM Series 350 USER MANUAL...
Page 21: ...Page 20 to 106...
