The Buyer's Guide to Advanced Supervisory Control

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The Buyer's Guide to Advanced Supervisory Control

Table of Contents

Watch the Buyer's Guide to Advanced Supervisory Control


Welcome to the Nexus Labs Buyer's Guide to Advanced Supervisory Control.

Dive into Advanced Supervisory Control with James Dice where he discusses the following:

- Why supervisory control matters

- Technology overview

- All the different buzzwords

- Marketplace categories and their differences

- Top 3 buying considerations

- 3 slides each from 5 top vendors

- Q&A with top vendors




Welcome to the Nexus Labs Buyer’s Guide to Advanced Supervisory Control (ASC). 

Longtime Nexus Labs community member Graham Henderson coined the term “the three S’s”. They are vital to a building’s performance. They are: 

  • Schedules: When should equipment run?
  • Setpoints: What is the system trying to do?
  • Sequences: How does the system achieve the setpoints?

The three S’s act as an excellent foundation for what it means to control a building. Unfortunately, legacy controls often suck at performing the 3 S’s. For years, people in the industry have blamed building operators for poor building performance while the archaic control software running the buildings remains unchanged.

So why haven’t the majority of building controls improved over the decades? For starters, controls vendors aren’t incentivized to make building controls easy. The primary customer for control software providers is not the building operator or occupant but the service provider. And that service provider gets paid to maintain and install the complex control. This has historically bred an industry of proprietary offerings and stifled innovation.

Adding to the three S’s, six fundamental control software capabilities have been since the 1980s: scheduling, setpoints, sequences, alarms, graphics, and trending. The three “non-S” capabilities provide the insights the building operator has historically used to maintain the building. But these insights, historically, are nothing to write home about. 

The first issue is that control software doesn’t diagnose or detect problems, and it’s up to the human operator to manage overrides and perform functional testing. The graphical interface, acting as the communication medium between the control system and the operator, simply hurls overwhelming, unorganized data across the human/machine chasm, and building operators are left trying to take action from the data.

The second issue is that control software isn’t managed well at scale, made to be enterprise, or easily integrated with other systems. At Nexus Labs, we often go back to the analogy of a silo. As our tech becomes ever more connected, a system that doesn’t play nice with others is automatically a detriment. 

The third issue is that these legacy controls are inherently wrong at enabling new use cases. For example, in the post-COVID era, it’s not uncommon for a building operator to want to improve indoor air quality (IAQ) while lowering overall building energy usage. Old controls simply can’t balance these competing demands.

So, as a building owner, what can you do to overcome the obstacles of legacy control? You can rip and replace old systems, which can be costly but also a breath of fresh air. Or, you can leave the existing devices in place but move the supervisory software function from the device layer to the application layer. That’s Advanced Supervisory Control.

Quick side note: if you’re new to the buyer’s guides, you should know that this is buyer’s guide #6 in the series. There was an intention to the order of these buyer’s guides. To better understand the layers Nexus Labs uses as the framework for smart buildings, you should start at the bottom, the device layer. Check out this Buyer’s Guide on HVAC and Lighting Controls.

Key Takeaways

Technical Overview

Today, the brain of supervisory control lives in a local building server and local supervisory controllers. If you had nine buildings, your portfolio-architecture would probably look something like this:

Moving the supervisory control up the stack is like chopping off each local system's head and sending supervisory commands from the cloud layer centrally.

Let’s take a second to remember that these architectural examples are typical of more significant, more complex buildings. Nexus Labs has previously published a whitepaper about the fact that 87% of buildings today do not have any controls: The Untapped 87%: Simplifying Controls Technology for Small Buildings. Moving up the stack for smaller, more straightforward buildings can be as simple as a cloud-connected thermostat that’s controllable via a mobile application. 

We also need to address the buzzwords surrounding the industry that can confuse buyers. Things like AI and machine learning are often used in advanced supervisory control but create more hype than they’re worth. Another phrase adjacent to ASC is automated system optimization (ASO). The US Department of Energy and other institutions use this phase to discuss trim and respond sequences that live in the cloud. ASOs are one type of energy management information system (EMIS), but others exist in different building verticals that HVAC control. Similarly, model predictive control (MPC) focuses on better ways to sequence equipment. Lastly, ASC can be called command and control.

So, ACS is just beginning to incorporate AI and ML, and it can be compared to an ASO EMIS and an MPC. Who could be confused by that….?

We’ve laid the foundation for how old building controls work and the concept of moving up the stack. Still, we’re yet to discuss emerging capabilities that merit the word “advanced” in advanced supervisory control.

There’s plenty of room to improve within the three S’s. Schedules can become more intelligent to help equipment run only when required. This is done by incorporating occupancy sensor data and optimizing start/stop times based on weather data and historic building performance. Building performance can be improved through dynamic temperature and pressure setpoint adjustments based on multiple variables - often called “setpoint resets.” Sequences can be enhanced by incorporating many advanced strategies in ASHRAE 36, which is becoming more commonly referenced within building specifications.

Beyond that, moving supervisory up the stack enables more computational power and an infinitely more expansive range of data to collaborate with. ASC can allow a building to manipulate its load to work with grid flex markets. Picture a California building raising its cooling setpoints when the sun goes away, and the grid becomes reliant on fossil fuels instead of solar panels. ASC can juggle competing demands, like the above mentioned IAQ vs. energy efficiency example.

Want a real-world example of how the migration to ASC helped a building owner? Check out our recent case study and podcast on the journey of the University of California, Irvine.

The early emergence of ASC products today puts us in the middle of the disruption of the supervisory software industry. Unlike legacy building controls, modern ASC living on the application layer isn’t very particular about what physical devices it communicates with. This creates a commoditized device layer that can be more competitively bid. 

Let’s discuss the actionable factors a building owner needs to consider to bring their portfolio to the modern era of ASC.

Remember that the application layer depends on the device layer. A building owner needs to be familiar with the capabilities of their devices. A brittle device layer may only speak in proprietary protocols and must be replaced before control can move to the application layer.

It’s also important to acknowledge that moving control to the cloud introduces a new connectivity threat with internet outages. Appropriately applying ASC includes having backup control at the local level so that in the event of an outage, there are fallback schedules, setpoints, and sequences that can keep operations running.

Don’t forget that software cannot fix physical issues. If there is a physical blockage in your ductwork, ASC can’t pull it out of the duct. This is why it’s commonly recommended to add fault detection and diagnostics (FDD) to support the ASC and improve troubleshooting insights for the maintenance team.

Finally, a software upgrade is only as valuable as the use cases it supports. ASC does not, and will not for the foreseeable future, replace the job of a building operator, but it does change the job of the building operator. Building operators need to understand how to use the new software and believe this will improve their jobs. Additionally, operators are retiring at an ever-increasing rate. Many building owners consider ASC a way to digitize the tribal knowledge in a building operator's head.

Marketplace Options

We split today’s marketplace options into two categories.

#1 - Companies focused on the optimization of HVAC. 

These companies focus on improving schedules, sequences, and setpoints. However, they typically don’t provide graphics or other UI improvements. This may be a good option for a building owner who is happy with how operators interact with their building but wants to benefit from advanced energy-saving tactics.

#2 - Companies providing a comprehensive data layer coupled with applications.

These companies provide all the fundamental requirements of building control and add things like FDD and schedule optimization. With this more holistic approach, buyers benefit from “a single throat to choke” since you are more or less using one vendor for all of your control needs.

Buying Considerations

Before purchasing, the buyer should be able to tie a control's improvement to specific examples of improved use cases. (Use our article on Demystifying Use Cases for inspiration) 

A buyer needs to feel confident their building is ready to move to supervisory control by being able to answer these four subquestions.

  1. Are the devices ready to accept commands from the cloud?
  2. Do you have the network infrastructure?
  3. Do you have the process to fix broken control components?
  4. Are the operators engaged, willing, and trained on the new software layer?

Finally, go back to the cost-benefit analysis.


What value, monetary or otherwise, will your company receive from optimizing current controls? What costs can it reduce?


What will it cost to enable ASC? Updates to network architecture, physical infrastructure, training, and IT enable secure cloud connections. Also, anticipate new subscription costs associated with ASC on the application layer. Legacy BAS may have had fewer recurring costs associated with hosting it locally.

If you’ve read this write-up and are interested in learning about the specific ASC products that vendors are selling, fill out this form!

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