29 August 2025
Central air compressor controls explained - A quick guide
Using multiple smaller compressors can often be more efficient than relying on a single large unit. To get the most out of this setup, central control is key.
In this article, we’ll explore how central controllers help optimize performance, balance workloads, and reduce energy use. Whether you want to extend equipment life or prioritize efficiency, central controllers make it possible.
Atlas Copco offers a range of central controllers, each with unique benefits. Let’s take a closer look to help you find the right fit.
Central controllers for compressed air explained
Atlas Copco offers four central controllers: Equalizer 4.0, Equalizer 4.0 PRO, Optimizer 4.0, and Extender+ designed for different needs. Let's look at all four to determine which one is the best fit for you.
Equalizer 4.0
The Equalizer 4.0 is a base model that is easy to install and program. It ensures the optimal operation of your individual units and your system as a whole. This central controller can help you reduce your pressure band and maintenance costs while also decreasing your downtime.
Equalizer 4.0 PRO
The Equalizer 4.0 PRO is more advanced. It offers reliable and smart machine control. With advanced visualization and trending data, you can easily monitor your compressor and AIRnet piping system's performance. On top, you have the possibility to integrate with SMARTlink.
In addition, this central controller offers excellent flexibility and ease of use. The Equalizer 4.0 PRO is a great choice for users who want advanced features while keeping their capital expenditures down.
Optimizer 4.0
The Optimizer 4.0 is our most performant central controller, designed for compressed air users who want it all.
This gives its users the capability to enhance every element of their air compressors' performance.
This translates into
- extra energy savings,
- a very low total cost of ownership,
- less CO₂ emissions
However, the Optimizer 4.0 offers a wide range of additional functionalities. It offers advanced compressor and process visualization to allow you to keep an eye on all of your units. And its extended connectivity features always put your mind at ease. Because you can rest assured that this central controller takes care of everything for you.
Optimizer 4.0 S
The advanced S package ensures that the full potential of your control system is realized, especially in changing conditions or when demand fluctuates.
Extender+
The Extender+ is a crucial add-on for the Optimizer 4.0, enabling smart control of valves, heat recovery systems, and chillers.
Together with the Equalizer 4.0 PRO and Optimizer 4.0, the Extender+ integrates a wider range of equipment, synchronizing operations to enhance performance, and reduce power consumption. It operates the dryers, cooling system and gas generators in an efficient way that the running hours and power consumption is reduced, resulting in a smaller carbon footprint. It minimizes running hours and maintenance costs, extending equipment lifespan and increasing uptime through a redundant machine setup, ensuring reliability and operational efficiency.
Air compressor controls compared
Comparing Equalizer 4.0, Equalizer 4.0 PRO, Optimizer 4.0 (S), and Extender+
It’s not just their technology that sets Equalizer 4.0, Equalizer 4.0 PRO, Optimizer 4.0 (S) and Extender+ central controllers apart.
- The Equalizer 4.0 can monitor and manage up to six compressors and monitor different dryers. It ensures a minimal unload time and is able to reduce your pressure band. That can result in significant energy savings. Keep in mind that every pressure reduction of one bar yields about 7% in energy savings.
- The Equalizer 4.0 PRO can control up to eight machines and comes with some optional connectivity options. It can equalize the running hours of these units and offer a reduced pressure band. That not only saves energy but also ensures the equal usage of all your compressors.
- The Optimizer 4.0, on the other hand, can control up to 30 machines, 30 dryers, and three AIRnet systems. The energy monitoring possibilities that are optional for the Equalizer 4.0 PRO are standard for the Optimizer 4.0.
- Ensures reduced load cycles lowering the overall energy consumption for the current flow demand.
- Increases your machine lifetime by keeping the machines at their most optimal operating points and avoiding unnecessary stress and damage.
- Saves you money by lowering your energy bills and maintenance costs.
- Improves your productivity by ensuring that your machines are always ready to meet the flow demand and avoiding downtime.
- Thanks to its visualization features, you can always keep an eye on energy insights and external measurements.
- The Optimizer 4.0 S has the same specifications as the Optimizer 4.0, but offers additional savings when air demand fluctuates thanks to AI-driven features.
- Optimizes your system performance by continuously adjusting the control parameters based on real-time compressor data.
- Reduces your energy consumption by automatically lowering the pressure setpoint based on actual and future consumption.
- Prevents disruptions by continuously monitoring operating parameters to proactively schedule service actions.
- Annual updates keep the Optimizer 4.0 S up-to-date with AI features, with a Subscription to a new or existing Optimizer 4.0.
- The Extender+ is a complementary addition to the central controller family. While the Equalizer 4.0, the Optimizer 4.0 and the Optimizer 4.0 S focus on compressors and dryers, the Extender+ expands optimization to the entire utility room, dynamically controlling chillers, valves, and gas generators to reduce energy use and ensure reliability of the whole system.
The Optimizer 4.0 edge for different compressors
If you operate only the same size of units, then the Equalizer 4.0 PRO controllers are a perfectly fine choice. The controllers will simply start the next machine in sequence based on a central pressure measurement.
The Optimizer 4.0, however, knows the type, size, flow, power and status of your machines. This allows these central controllers to decide which units to start/stop next to optimize their performance and efficiency.
Additionally, the Extender+ enhances the Optimizer 4.0 by enabling smart control of machines like valves, chillers, and dryers, synchronizing operations for increased efficiency and reduced maintenance costs. Together, the Optimizer 4.0 and Extender+ allow you to enjoy the full Atlas Copco smart central controls offering. You get to save energy and reduce your total cost of ownership.
You can take your operation to the next level with the Optimizer 4.0 S. AI-driven algorithms automatically adjust control parameters and continuously learn from system behavior, further optimizing performance and minimizing energy consumption.
We hope this guide has given you a handy overview of the different central control technologies. If you still have questions and want to get compressor controls explained by one of our experts, contact us today!
