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
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 27 — Time Of Day Action Operation
You can define up to 2 peak time periods of the day in the Maintenance > Relay & Load Shed screen:
1. In the Time of Day Action Configuration dialogue box, set up the start and end time of the first rush hour
under Time Period 1 and the second rush hour under Time Period 2. In this example, during the first time
period (7 AM to 9 AM), all 3 timers are disabled (they do not count down at all). Similarly, all timers are
disabled during the second time period (3 PM to 6 PM).
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