Clint’s Controls Corner: Sequence of Operations


Clint's Controls Corner (text only)

In this month’s “Triple C,” I would like to discuss the importance of defining the sequence of operations of the lighting control system early in the design and specification process. The advanced control systems being used today offer a variety of programming options and flexibility in how the system will operate. The end goal of any control system is to maximize energy efficiency, and meet the requirements of energy codes in a way that is simple and seamless for the building occupants to operate. If the ultimate functionality of the system is not defined, the full value of the installed control system may not be realized.

Basic operation details should include specifics on how the system will operate, broken down by different space types within the facility. Details should include whether a space will have automatic lighting controls that are time based or occupancy sensor based. Rarely is it advisable to provide both time based and occupancy based controls for the same fixtures, as this adds complexity to the system which increases the potential for incorrect operations. If time based control is specified, specific time schedules laid out in advance will ensure that the system will operate as intended. For spaces with occupancy based control, it is important to note if the space will operate as manual-on, automatic-on, or automatic-on to a specific light level less than 100%. (IECC 2015 allows automatic on to 50% light level only.)

To maximize energy savings, automatic daylight harvesting is also included. It is critical to show the daylighting zone on the floor plan, and define the target light level to be maintained within this zone. With daylight harvesting, the user controls in the space can be a single control for the entire space, or separate controls for the daylight zone and the remaining area. This, and whether the daylighting can be overridden by occupant controls, needs to be specified.

Systems with color changing or color tuning fixtures require additional attention. The operation of the lighting in these spaces can vary from simple pushbutton static color control, to a variety of user programmable dynamic lighting chase scenes that are triggered by specific operations or time schedules. For networked systems with front end computer interfaces, or building automation system integration, it is crucial to define which control points will be modifiable from where. The sequence for these spaces will not only ensure correct operation, but will also guide the selection of appropriate control components for the specific application. 

Advanced lighting control systems will require some form of programming to meet the desired operation of the system. The technicians that complete this programming need to have direction on how the system is intended to operate. If the sequence is not defined anywhere on the construction documents, the programming technician will often have to make assumptions on how the space will operate. This may not always meet the design intent for the space. 

To improve upon ensuring that the intent is appropriately defined, MH Controls includes a detailed sequence of operations in the submittal documents provided for customer review. Documenting the sequence of operations in advance will allow all parties of the design team to provide comments, and will offer specific direction for the programming technician onsite. 

Achieving the best lighting controls for specific spaces requires a defined sequence of operations, and a system capable of achieving the specified sequence. To maximize the value of the control system, the specific details of how all aspects of the system will work should be defined well before construction begins.

This article was written by Clint Conley, our Lighting Controls Department Manager. Clint can be reached at 720.904.8554 or