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.

1. Classic wall switches are used exclusively as local control switches, when it is hindered by space limitations then they are unable to be used.
2. 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.
3. 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.
4. It is difficult to implement multiple access with classic switches. For big flat open spaces, it is very difficult to have duplicate access.
5. 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.
6. 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.

Different customers have different views on how a lighting control system adds value to their application. They can grouped into five main types:

First Type: Extravagance, to add luster to a building through technology

In order to show off how upscale a building is, having a lighting control system is like the adornment of smart technology.

Second Type: Highlight energy saving and intelligent building

This is the typical smart green building, everything is made to emphasize intelligence and energy savings. Striving for both intelligence and energy saving in order to gain prestige and accolades. Whether or not the system is effective is beside the point, to emphasize its uniqueness is what its all about.

Third Type: Emphasis on energy savings

This type implements a lighting control system for its practicality in effecting energy savings, but in addition it seeks to achieve labor savings for the facility management, ease of maintenance, and the reliability of the system. They don’t care much for the prestige and is not for showing off and care most for the cost to performance ratio.

Fourth Type: Mood lighting

The emphasis here is in how the lighting would be able to create the desired ambience and the ease of which any transition (scene recall) can be made.

Fifth Type: Technology benefits

Fanatic of technology, the focal point is in the fancy benefits that technology can bring. Everything should be controllable from a mobile phone, a computer, touch panel or any high technology user interface device. They especially wants to deemphasize the use of any form of wall switches.

Sixth Type: Bid tender specifications

The focal point is on specifications, on having specifications that are unique to the system to give the bidder an edge over the competition.

At its core, DAE’s lighting control system is an “energy saving lighting control system” in contrast with plain “full 2-way lighting control system.

Most customers have appraised DAE’s system as being: practical, easy to use, helps to save energy, economical, reliable and durable.

1. Utility

   In addition to large open spaces, DAE’s lighting control system is also well suited for the energy saving control of enclosed spaces, and can also work with classic wall switches and ordinary infrared sensors.

2. Engineering
   1. No Achilles heel. Not reliant on a central processor and no need for system power supply means that there is no single point of failure that can cripple the entire system.
   2. Top-notch safety backup capability. Easy to maintain.
   3. Installation setup is very easy to do, no special tools nor software needed. It can be done by the user themselves.
3. Integrability
   1. Can be integrated into third party systems through either Modbus or Modbus TCP/IP.
   2. Touch panel user control interface: easy to use and affordable; can even be linked to a mobile phone, computer or tablet.
   3. Synchronize multiple hosts. Fast response, mutually redundant.

Black cat, white cat, any cat that catches mice is a good cat. The point of this quote is that the color of the cat is irrelevant, the way to judge a good cat is whether it catches mouse or not. In the same way, a good lighting control system should be judged objectively.

1. Feature evaluation
   1. Can the lighting control system effectively save energy?
   2. Can it be combined applications that require dimming?
   3. Can it be used with regular sensors and classic wall switches?
2. Cost considerations
   1. Material cost
   2. Setup service
   3. After sales service cost
   4. Future expansion of additional circuits
3. System safety
   1. System failure
      It should be able to avoid having a single component failure causing the collapse of the entire system.
   2. Backup
      When a failure does occur, there should be a means of backup control which would not affect normal operations.
4. Maintenance and reliability
   1. Maintenance cost
      This is a big point. One should avoid being able to afford the initial cost but not the maintenance cost. It should not be such that once the warranty period is expired, the entire system becomes a fancy but useless ornament.
   2. DIY maintenance should be simple and easy
      Maintenance shouldn’t be reliant on the vendor, the building manager should be able to do replacements or perform maintenance by themselves, setup should likewise be easy to perform.
   3. Reliability
      Portions involving high voltage electrical power should be internationally certified. It should be designed to match the special characteristics of certain lamp types.
5. Operation and management
   1. Operation
      A lighting control system is equipment that needs to be operated, it should be able to satisfy the needs and be convenient to both the local user and the remote administrator.
   2. Real time response
      The response time from when a command is issued from the centralized control touch panel to its execution and feedback response should be fast and in real time.
   3. Schedule should be easy to set up
      Setting up the automated control schedule should be simple and easy (almost as straightforward like setting up a digital alarm clock)
6. Third party integration
   1. It should be possible for third parties to integrate into the system.
   2. It should be able to accommodate both the safety and alarm capabilities.

Comparing an Energy Saving Lighting Control System with a Full-2Way Lighting Control System
Full-2Way Lighting Control System: Replaces a traditional switch with a centralized control and local controls which are connected through a digital trunk bus, allowing control to be made from both the local site or remotely.
Energy Saving Lighting Control System: A further advancement which incorporates sensors into an energy saving system. Creating a system that can be controlled from local switches, central control and motion sensors.
A more complete definition would be to include safety, lighting, small room fans combined into one system. A concrete example would be a hotel guest room control system.

1. When the guest leaves the room, the lighting and air conditioning will all turn off or will enter energy saving mode.
2. At any time, the central control system can determine the status of the safety, lighting and air conditioning in the room.

A. System Architecture 

1. Multiple touch panels can be used in the same system, not only are the status of the lights shown, but the execution and response is very fast, they are low cost and high reliability.
2. Pattern switches work differently. Unlike in a full-2way system, they do not need an MRS (Main Remote Station) to work, and they don’t require any special programming. They can issue both pattern and group commands independently.
3. Integrates both lighting and safety at the same time on the same touch panel screen.
4. Easy to set up schedule, allowing the end user themselves to make any changes without the need for special software or qualified technician.
5. Can be integrated into third party systems. It communicates the industry standard Modbus protocol, which allows it to be linked (via either RS485 or TCP/IP) to any system that supports it.
6. The touch panels can be uplinked to a network and synchronized with multiple types of devices including PCs, mobile phones or tablets for the purpose of remote control.

Installation, Maintenance and Reliability

1. With a Japanese branded full-2way lighting control system, once the MRS unit containing the CPU fails, then the entire system collapses and all the patterns and groups that have been set needs to be reconfigured. Contrast this with DAE’s system where there is no CPU to worry about, and hence there is no central point of failure.
2. Each of the controller modules in DAE’s line up contains manual control buttons on board that can be used as backup control that can directly control the lights that is connected to its channel. These can also be used after installation for verifying the installation, or for diagnosis and testing during repair.
3. Since there is no need of a unit such as the MRS, then the entry level cost is greatly reduced as this unit is the single most expensive unit when adopting a Japanese branded full-2way lighting control system. Thus even a small establishments such as restaurants, libraries, offices can adopt this system with a small budget.

Lighting Control Modules

1. There is no need for the prohibitively expensive proprietary TR system power supplies that is needed by the Japanese branded full-2way lighting control system.
2. Three forms of controller modules available for every kind of situation: Controllers specially designed for contactor use, controllers with built-in relays, and controllers with external relays.
3. Smart TUs, each controller is equipped with manual control buttons for each lighting channel that it controls, and the auto-learning logic built-in that enables each controller to learn patterns and groups. Which make them easy to configure, test and maintain. They do not need any special device for configuration, and can be done by a non specialized personnel.
4. Smart interactive energy saving control modules:
   Can accept sensors and classic wall switches, they have special energy saving logic built-in. They are inexpensive and easy to maintain.
5. DAE’s lighting control system includes modules for LED dimming, with more channels that those available from competing full-2way lighting control system.

1. No flexibility
   When there is the need to make an immediate change for a special event or a holiday, sometimes there is barely enough time to run all over to make the adjustments to meet the event.
2. Outdoor or daylit area lighting
   When the natural lighting times change with the seasons, the timer would also need to be adjusted to match which is also troublesome.
3. One timer, one panel
   Even though there would only be one setting for the timer for any given month or season, any single timer can only be used in any single panel. In a large building, it is certain that there would be multiple panels to cover different sections of any area or floor. To match the natural lighting, the timer needs to be adjusted accordingly with the month or the season, but with so many panels, this would become too cumbersome as the building manager would have to run all over to make the adjustments.
4. Incorrect or inaccurate time
   It is recommended that a lighting control system be installed and each section would have the lights controlled by the LT3100, LT3704 or some other controller modules, the control for these modules would then be centralized on an ACS touch panel. The ACS panel would be set with the desired time schedule, the ACS would be connected to the host PC, the PC would then be able to propagate its clock time to all ACS that is connected to it.

The Role and Value of Digital Switches in the Lighting Control System of a Public Building

A digital switch is not simply a new type of high end switch, but is entirely different from a classic switch. A digital switch is able to achieve that which not possible with a classic switch.

What is a Lighting Control System?

A lighting control system is a way of optimizing the wiring for the lighting as applied to a public or commercial buildings. Digital switches connect to the lighting control panel through the digital trunk line constitute an entirely different method of wiring setup as compared with the traditional form of wiring made up of classic switches through electrical power circuits.

The Role of the Switch

No matter what type of switch, its one indispensable function is the convenience of operation that it should provide to the user.

When this switch is operated, it should tell the lights to turn on or off, thus a wall switch is made for the convenience of the user.

Evaluating a Good Switch from a Bad One

1. The closer the switch is to where the user needs it, the better the switch is at serving its purpose. The faster its feedback and the more lights that it can control, then the more convenient it is. The opposite is when the user needs to travel far then the poorer the switch is at doing its function.
2. The more straightforward  and intuitive the switch is to use, the better the switch is. On the other hand, when the user is faced with a wall of switches, then it is not obvious which switch controls which light. Especially cumbersome if several group of switches needs to be operated just to find the right one.
3. The easier it is to configure or adjust the switch to meet the partitioning of the space, the better the switch.
   In order to meet the needs of any given public or commercial space, the space often needs to be partitioned in a manner appropriate for its intended use. In the traditional method, since the lights and switch are in a one to one absolute correspondence, there is absolutely no flexibility, in order to change the layout, the wiring needs to be renovated physically, which is laborious, expensive, time consuming and disruptive to the business.

A lighting control system is used mostly for the control of the lights in public facilities, and they can either become a standalone system or a subsystem of the building automation system. In which case, why not just just the DDC for controlling the lights as well. 

The focal point of a building automation system is the control center. But in a lighting control system there can be both a centralized control and local control, in some cases, local control can even have multiple access points and even scene recall capability.

To further elaborate:

1. Local digital switches have status feedback
   This is one of the more prominent features of the local switches of a lighting control system. Having local control and scene recall is a very basic requirement of a lighting control system, this is demonstrably a feature that cannot be performed by the administrator at the control center. Lighting control is a control system that requires both local and central dual control.
2. For small scale applications, simply use digital switches
   Such applications often does not require the involvement of a computer based central control system, where one can simply use either the multiple digital switches or a touch panel as the user interface for centralizing control of all the lights. Such a setup is inexpensive, easy to implement, simple and convenient to operate.
3. For medium scale applications, one can implement a standalone central control system, and also integrate it into the BAS.
   The D-Bus lighting control system has an open Modbus protocol that can be used by the graphical control software on a host computer to interface with; of course, the BAS software can use this to interface with the D-Bus lighting control system as well.
4. For large scale applications, it is strongly recommended that one have a single centralized point of control. Otherwise, there would be far too many touch panels distributed all over to control the lights in various areas. It is further recommended that there should be a second duplicated central control in case the first one fails.
5. Cost and backup considerations
   Even if only the central control is implemented without any local controls, the cost is still much lower than that of a BAS. One should also consider that when the central control host fails, then there must be some form of backup control, on this point, it is also easier to implement this in a lighting control system and the cost is also much lower.
6. Lighting is a high voltage system
   (hardware wise it is inadequate, because of small relays, colossal engineering cost, multiple wires)
   A BAS specializes in central HVAC control and the safety system, while a lighting control system specializes in lighting control. Even though a BAS can be used for lighting control, doing so is clumsy and expensive, since each control point needs to have its own contactor and wiring, all the wiring combined will result in a mass of wires snaking from panel to panel.
   Contrast this approach with a dedicated lighting control system wherein the hardware components are designed specifically for lighting. Which results in simplified engineering work and greatly reduced costs.
   If the building does not have central HVAC, but instead uses local air conditioners such as box types or split type air conditioners, or  if they don’t have any air conditioners at all, then the BAS would be used exclusively on lighting and its strong suite would be completely wasted. In which case why not simply use a dedicated lighting control system in the first place.
7. Combining monitoring with control makes things more direct and reliable.
   The most expensive hardware portion of a BAS is the DDC, and since it is a low voltage system; every lighting load that it needs to control would be through its DO ports controlling the intermediate magnetic contactors. While the status feedback would return to the DDC through its DI ports.
   In contrast, in a dedicated lighting control system, the controller and the relay is combined together and there is no need for an external magnetic contactor,
   In a lighting control system, the load control and feedback are combined into the same unit. The wiring is more straightforward and there is no need for any separate DI ports for the feedback signal. There is also no need to perform any sort of special programming as all the logic is already built into the unit.
   In a BAS, all of these are considered as separate and extra material, panel wiring and programming costs. Of course, all of these costs is greatly reduced or obviated in a lighting control system, with the additional benefit of less space occupied.