What Is a JACE Controller? The Tridium JACE Explained

A JACE (Java Application Control Engine) is Tridium's Niagara controller that connects, controls and serves a building's HVAC, lighting and metering systems.

If you have opened a BMS panel in a commercial building built in the last twenty years, there is a good chance you have seen one: a compact DIN-rail box with a Tridium or Vykon logo, two network ports and a row of RS-485 terminals. This guide explains what a JACE controller actually does, where it sits in a building management system, how the models differ, and how to decide between a JACE 8000, a JACE 9000 and the IONA Niagara 4 controller.

What does JACE stand for?

JACE stands for Java Application Control Engine. The name comes from the Niagara Framework itself, which is written in Java and runs inside a Java virtual machine on every device it is installed on. A JACE is simply the embedded hardware Tridium designed to run a Niagara station at the edge of a building network, close to the plant it controls.

You will sometimes see it written as "Jace", "JACE controller", "Niagara JACE" or "Tridium JACE". They all mean the same family of products. In the United States you will also find JACEs sold under other brand names (Honeywell, Johnson Controls, Distech, Lynxspring and others) because Tridium licenses Niagara to OEM partners. Underneath the label it is the same Niagara station.

What does a JACE controller do?

A JACE does four jobs at once. Understanding them is the key to understanding why the JACE became the default building controller for open, multi-vendor systems.

1. Protocol integration

A typical building has equipment from many manufacturers that speak different languages: BACnet MS/TP from VAV boxes, Modbus RTU from energy meters and chillers, BACnet/IP from air handling unit controllers, LonWorks from older lighting systems, M-Bus from heat meters, and proprietary protocols from fire panels or Trend outstations. A JACE runs a driver for each of these. Each driver turns the device's data into Niagara points, so a temperature from a Modbus meter and a temperature from a BACnet VAV look identical to the rest of the system.

This is the JACE's main purpose. It is a multi-protocol integration controller first and foremost.

2. Control logic

Once data is normalised into points, the JACE can run control strategies on it: time schedules, interlocks, optimum start, PID loops, setpoint resets and alarm handling. Logic is built graphically on the Niagara wire sheet by linking components together, rather than written as code. On smaller sites the JACE is the only controller doing supervisory logic; on larger sites it coordinates field controllers that run the fast plant loops themselves.

3. Data logging and alarming

The JACE stores histories (trend logs) of point values and raises alarms when values go out of range or equipment fails. It can email alarms, forward them to a supervisor, or keep them locally until an engineer acknowledges them.

4. Web serving

Every JACE has a built-in web server. Users log in with a normal browser to see HTML5 graphics, adjust setpoints, change schedules and acknowledge alarms. No client software is needed for day-to-day operation. Engineers use Niagara Workbench for configuration.

Where a JACE sits in a building management system

Most Niagara BMS designs follow a three-tier architecture:

A single JACE can be the whole BMS on a small site such as a school, retail unit or office floor. On a hospital or university campus, dozens of JACEs report up to one or more supervisors, which aggregate their data into one interface.

The JACE talks upwards to the supervisor over the Niagara network using the secure Fox protocol (FoxS). It talks downwards to field devices over BACnet, Modbus, LonWorks and the other drivers.

JACE models through the years

Tridium has released several generations of JACE. Knowing which one you have matters because it decides which Niagara version you can run, and therefore which security patches and drivers are available.

JACE 8000

The JACE 8000 launched with Niagara 4 and became the most widely installed Niagara controller in the UK. It has two Ethernet ports, two RS-485 ports, optional Wi-Fi, and accepts up to four plug-in expansion modules (extra RS-485, RS-232 or LON) without tools. Remote I/O is added with Tridium's NRIO modules.

The JACE 8000 will not run Niagara 5. Niagara 4.15 is its final version, and the controller is now end of sale in Europe. If you are planning work on a JACE 8000 site, read our JACE 8000 to JACE 9000 upgrade guide before you buy anything.

JACE 9000

The JACE 9000 is the current Tridium controller. Its key specifications:

• NXP i.MX 8M Plus quad-core processor and 2 GB LPDDR4 RAM
• 8 GB removable microSD for the licence and station, plus built-in eMMC
• Two 10/100/1000 Ethernet ports and two isolated RS-485 ports
• Optional Wi-Fi 5 (802.11ac) as client or access point
• Batteryless design with real-time clock and secure boot
• 24 VAC or 24 VDC power, operating range −20 °C to 60 °C
• Up to four expansion modules (maximum two RS-485 modules) and up to 16 remote I/O modules
• Base licences from 100 to 10,000 points, with point upgrade packs

Most importantly, the JACE 9000 is supported on Niagara 5, which makes it the safe Tridium choice for any new project.

Edge 10

The Niagara Edge 10 was Tridium's small edge controller with onboard I/O. It is now end of life: the last time buy in Europe was 31 December 2025, and hardware support ends in July 2028. Our Edge 10 end-of-life guide covers the replacement options.

JACE vs IONA: what is the difference?

The IONA Niagara 4 controller is designed and built by Tyrrell Products. It runs the same Niagara 4 station as a JACE, so drivers, graphics, logic and Workbench all work the same way. The difference is the hardware around it:

If a plant room needs a supervisory controller and local I/O, IONA can remove a separate I/O module and its wiring. If the building needs wireless sensors, the IONA-I's built-in LoRaWAN gateway removes a separate gateway too. Read the full IONA vs JACE comparison for detail.

How much does a JACE controller cost?

A JACE's price is driven by its licence, not the hardware. The controller is licensed for a number of points (the Niagara Global Capacity licence) and for the drivers and features enabled on it. A 100-point JACE 9000 for a small plant room costs a fraction of a 5,000-point JACE integrating a whole building.

Other costs to budget for:

• Software Maintenance Agreement (SMA): gives you access to new Niagara versions and security patches. Without an active SMA you cannot upgrade the controller's Niagara version.
• Third-party drivers: some integrations (Trend, Gent fire, LoRaWAN decoders) need a driver licence on top of the base licence.
• Expansion modules and remote I/O if the site needs extra serial ports or hard-wired points.
• Engineering time: integration and graphics usually cost more than the hardware.

You can see current UK pricing on our Niagara controllers category. If you are not sure which licence size you need, our guide to calculating Global Capacity points explains how points are counted.

How do you set up a JACE controller?

The high-level commissioning steps for a new JACE are:

1. Connect a laptop running Niagara Workbench to the JACE's secondary Ethernet port, which has a known default IP address, or use the JACE's discovery tools.
2. Open a platform connection and log in with the platform credentials. New JACEs force you to set strong credentials on first commissioning (see JACE default credentials).
3. Run the Commissioning Wizard. It installs the licence and certificates, sets the IP address, date, time and time zone, installs the software modules the station needs, and copies the station to the controller.
4. Add drivers (BACnet, Modbus and so on), discover devices and create points.
5. Build logic, alarms, histories and graphics.
6. Join the JACE to a supervisor over the Niagara network if the site has one.

Watch the Niagara 4 TCP lab videos, particularly LAB 05 on JACE communication, to see this end to end.

How do you reset a JACE controller?

There are two kinds of reset and they are often confused:

• Restarting the station or rebooting the platform. Done from Workbench (Platform Administration) or by cycling power. Nothing is lost.
• Factory reset. Returns the controller to its shipped state, removing the station and user accounts. On a JACE 8000 this is done with the reset button during power-up. It needs care: older JACE 8000s can lose network connectivity after a factory reset (see restoring connectivity on a JACE 8000), and you will need the licence and a station backup to bring the site back.

If you are locked out rather than broken, you may need a platform reset token or serial shell access instead of a full factory reset.

When is a JACE the right choice?

Choose a JACE (or IONA) when:

• the building has equipment from several manufacturers that must work as one system
• you want a browser-based front end without licensing client software per user
• you need open, vendor-neutral control so any certified Niagara integrator can maintain the site
• you plan to add analytics, cloud connectivity or IoT sensors later

A JACE is not the right tool for fast, tight control of a single item of plant on its own. That is the job of an application controller. In a well-designed BMS the two work together: application controllers run the plant, and the JACE coordinates them.

Frequently asked questions

What does JACE stand for in HVAC?

JACE stands for Java Application Control Engine. In HVAC it is the Tridium Niagara controller that integrates and supervises the heating, ventilation and air-conditioning controllers in a building.

What is a JACE in BMS?

In a building management system the JACE is the integration and supervisory controller. It collects data from field controllers over BACnet, Modbus and other protocols, runs schedules and logic, logs trends, raises alarms and serves the BMS graphics to a web browser.

Is a JACE a PLC?

No. A PLC is designed for fast, deterministic machine control. A JACE is a network integration controller and web server. It can run control logic, but its strength is bringing many systems together, not scanning I/O in milliseconds.

Can a JACE 8000 run Niagara 5?

No. The JACE 8000 is limited to Niagara 4, with 4.15 LTS as its final version. To move to Niagara 5 you need a JACE 9000 or another N5-supported controller.

What is the difference between a JACE and a supervisor?

A JACE is an embedded controller installed in or near the plant. A Niagara Web Supervisor is software running on a PC or server that brings many JACEs together, stores long-term history and provides enterprise-wide graphics and alarming.

Who makes JACE controllers?

Tridium, a Honeywell company, designs the JACE. It is also sold under OEM brands such as Vykon. In the UK, Tyrrell Products is a Tridium distributor and supplies JACE 9000 controllers, licences and upgrades.

Related guides

• JACE 8000 to JACE 9000 upgrade guide
• IONA vs JACE: which Niagara 4 controller?
• What is Tridium Niagara 4?
• How to choose a BMS controller
• JACE FAQs