The core value of having a lighting control system is the flexible and powerful local switches and it is not in the centralized control computer. This is because if all that is wanted is a centralized control system, then any BAS or a PLC based system could do just as well. Thus it is only the digital switches that make a lighting control system unique.
The point of having digital switches is not simply in it being in vogue because it is the latest in technology. But rather because this an advancement over classic mechanical switches, in that it can do what cannot be done with classic switches. Thus there is the need to examine what are the limitations and weakness of classic switches and see how they are overcome by digital switches.
- Classic wall switches are used exclusively as local control switches, when it is hindered by space limitations then they are unable to be used.
- Classic switches is based on a physical one to one wiring, and it must be connected to the actual electrical power wiring. There are many restrictions to how wiring can be physically laid out, and the cost for doing a one to one wiring is high, thus in a public space, wiring length is minimized by placing the switch close to the light that it controls. If it later desired that wiring changes need to be made for repurposing or due to poor initial location choices, then renovations would be difficult and expensive.
- Classic switches and the wiring circuit are bounded together, but the switch is meant to be close to where the user does their job. These two considerations are often in conflict.
- It is difficult to implement multiple access with classic switches. For big flat open spaces, it is very difficult to have duplicate access.
- It is impossible to implement any grouping or pattern. Groups and patterns are not only valuable for being able to simplify usage, but at the same time they can also greatly reduce the number of switches and amount of wiring needed.
- Only after making all the other considerations should attention be given to whether or not to have both digital switches together with centralized control in the same system. Then also consider whether an automated schedule control is desired.