The programmable logic controller (PLC) is an all-in-one control solution for residential applications. The PLC gives the homeowner that additional level of control over his home electrical requirements. One level of control the PLC offers is a Date/Time schedule feature. What the Date/Time schedule feature allows the homeowner to do is have various electrical devices, (lights, drapes, etc.) to automatically operate based on a pre-determined date or time. Most PLC’s have a built in date/time clock. Some PLC’s also have an astronomical clock which calculates the sunset/sunrise time for a given longitude/latitude coordinates.

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One obvious application for a Date/Time schedule is turning the home landscape lights on at sunset and off at midnight. The landscape lights will come on/off every night based on the preset times programmed in the PLC. If the homeowner wants to override this function, he only has to go to the keypad that controls the landscape lights and turn them on or off. The Date/Time schedule does not hold the output, (landscape lights), on or off.

Another application is to ramp on lights at some time before sunset. When the PLC reaches the preset time, (let’s say 15 minutes before sunset), the picture lights in the hallway start coming on and ramp to full on after 15 minutes. As it gets darker outside, it gets brighter inside.

If the homeowner has motorized blinds in the home, the Date/Time schedule allows the homeowner to lower his/her blinds whenever the sun light may be to bright. The blinds can then be automatically raised after the sun passes by. This feature is great in protecting expensive rugs, furniture or pictures from fading.

The Date/Time schedule is useful in many more applications. When connected to the security system status, the PLC could give the home a lived in look by turning various lights on/off at different times, only when the security system is armed in the away mode. Xmas lights would only turn on/off during the holiday season. All lights in the home could be turned off at some pre-determined time in the morning to ensure no one left lights on in some remote room in the house. The Date/Time schedule is a feature in the PLC that gives the homeowner a higher level of control over his/her day to day switching needs.