7
3.6
Sequence of Operation
The DLC-PDC operating sequence will be described below referencing Figure 3.
1.
At dawn the sensed light level increases approaching the High Level Setpoint through the
Low Level Setpoint, the Low Level Setpoint LED will switch ON, while the High Level
Setpoint LED remains OFF. The output relay is de-energized with the Relay Status LED
OFF and the lighting circuit ON. (See Figure 3A)
2.
As the sensed light level increases and passes through the High Level Setpoint, the High
Level Setpoint LED will switch ON energizing the Relay, and thus switching ON the Relay
Status LED, and switching OFF the lighting circuit. The Low Level Setpoint LED will remain
ON. (See Figure 3B)
3.
The above status remains through out the day as the sensor light level increases to the
maximum light level and then starts to decrease towards dusk. As the light level passes
through the High Level Setpoint the High Level Setpoint LED will switch OFF, leaving the
Low Level Setpoint LED ON, and the Relay energized with the Relay Status LED ON. (See
Figure 3C)
4.
As the light level decreases through the Low Level Setpoint the Low Level Setpoint LED
switches OFF. The relay de-energizes switching the Relay Status LED OFF, and thus
switching ON the lighting circuit. (See Figure 3D).
5.
As dawn approaches and the sensed light level again rises the lighting cycle is in position to
repeat again.
Figure 3: DLC-PDC Sequence of Operation
It is important to note that the output relay does not change state while the input signal is in the
deadband. The output relay will only change state when the ambient light level crosses the far
setpoint in the light level’s direction of travel.