There are many ways to integrate a BMS with Lighting Controls. For many years simple contact closure outputs connected to inputs in the lighting control panels were all that was required to give building managers control of their lights from the BMS console. This method has stood the test of time because it was simple to understand and easy to maintain.

In recent years, the need for more sophistication in the interaction of the lighting control and HVAC systems has caused the need for network protocols of both systems to communicate.

The two protocol standards ASHRAE has adopted are Bacnet and LonWorks. Both of these are widely used throughout the building controls industry. The question that arises is "What is the best way to integrate- gateway or native?"

A Gateway connects two stand alone systems that can have the same or different protocols, while a Native approach must be integrated as one system. Each way has its advantages and what follows will compare some of these from a lighting control perspective.

Gateway.

• Lighting Controls are stand alone and can communicate only through the gateway. Commissioning is done by the lighting controls supplier.
  
  
• Requires two data bases.
  
  
• Functionality is determined by the lighting control system.
  
  
• Lighting control system support and maintenance is usually provided by the building owner.

Native.

• Every relay panel within the lighting control system has a network node.
  Commissioning is done by the system integrator.
  
  
• Requires only one data base.
  
  
• Functionality is determined by the system integrator.
  
  
• System support and maintenance is usually provided by the system integrator.

Advantages of Gateway.

• Requires less integration time since the lighting control system will already be functioning as a stand alone entity.
  
  
• Simplifies system integrator tasks as there is only one device to integrate.
  
  
• Requires less commissioning time since lighting control systems have built in configuration and programming tools that speed up the process and can even be programmed before shipment.
  
  
• Functionality is determined by the lighting control supplier so the latest advancements in technology such as daylight harvesting can be implemented effectively.
  
  
  

Advantages of Native.

• Only one user interface for both HVAC and Lighting for the building staff to learn.
  
  
• Only one supplier is responsible for both HVAC and Lighting Control maintenance.
  
  
• System integrator is in control of obsolescence.
  
  
• All lighting control network variables are available to the integrator to use at their discretion.
  
  
• It is possible to specify either Bacnet or LonWorks open protocols and require the respective association standards certifications to be adhered to. This will define for the System Integrator what they have to allow for at bid time.

Douglas Lighting Controls has an array of products designed specifically for integrators and has integration specialists on staff to assist in design, integration and programming of systems. Go to Integration Products on the Douglas Website for more information on Douglas System Integration Products.