The MQTT Broker Service runs inside any Niagara 4 station, enabling local MQTT clients to publish and subscribe without the need for an external broker. It simplifies deployment, improves security, and retains full Niagara MQTT functionality. 

Key Benefits 

Solves a Common Problem 

Niagara and devices need an MQTT broker in the middle. 

Simple & Secure 

No external servers or Raspberry Pi required. Built-in security and certificate management. 

Flexible & Scalable 

License includes 2 client connections. Add more as needed up to your limit. 

Works Everywhere 

Runs on JACE, Web Supervisor or any third-party Niagara 4 controller. 

1. The Problem: Missing MQTT Broker 

A Niagara 4 Controller operating as an MQTT Client and a Third-Party Device operating as an MQTT Client require an MQTT broker between them. 

Without a broker, clients cannot communicate. Customers often install external brokers, such as Mosquitto, or Raspberry Pi solutions, which can be insecure and hard to maintain. 

2. Our Solution: Built-in MQTT Broker Service 

The built-in MQTT Broker Service runs within Niagara 4, connecting the Niagara 4 Controller and Third-Party Device. 

The MQTT Broker Service: 

• Runs inside the Niagara station with no extra hardware. 

• Is easy to configure with built-in security and user management. 

• Supports publish/subscribe with full Niagara MQTT functionality. 

Licensing Model 

The base license includes 2 client connections. 

Additional client connections can be added as required. 

Retained topics: Up to 50 on controller hardware, with more on Web Supervisor. 

3. Security & Connection Options 

Non-secure MQTT (TCP 1883) 

Disabled by default. Enable only if required. 

Secure MQTT (TLS 1883) 

Use Niagara certificates or import your own certificates. 

User Accounts & ACLs 

Create users and define read/write privileges to specific topics. 

Connection Options 

• Port (TCP) – 1883 

• Secure (TLS) – Enabled by default 

• Host – 0.0.0.0 (all interfaces) 

• Authentication – Anonymous by default or Broker Users 

• ACL Provider – Permit All by default or per-user ACLs 

We recommend using TLS with user accounts and ACLs for maximum security. 

4. Architecture Example 

The MQTT Broker Service runs within a Niagara 4 Station, including a JACE, Controller or Web Supervisor. 

The built-in MQTT Broker Service can connect to MQTT clients and devices, including: 

• IoT Sensor 

• Energy Meter 

• People Counter 

• BMS Controller 

• And more 

Typical Use Cases 

• Connect devices on site without installing an external broker. 

• Improve security and simplify maintenance. 

• Bridge data between Niagara and IoT devices. 

5. Getting Started – Overview 

Step 1 

Add the MQTT Broker Service from the palette to Services. 

Step 2 

Configure basic settings, including port, TLS, certificates and security. 

Step 3 

Optionally, create users and define ACLs for topic access. 

Step 4 

Restart the station and approve the broker certificate. 

Step 5 

Connect MQTT clients to the broker and start exchanging data. 

Step 6 

Monitor performance and adjust settings as required. 

Simple to set up, powerful to use. 

6. Configure the MQTT Broker Service 

The MQTT Broker Service is configured through the AX Property Sheet. 

The available settings include: 

• SSL Enabled 

• Port (TLS) – 1883 

• SSL Host – 0.0.0.0 

• Certificate Alias – Niagara Default 

• Authentication – Broker Users 

• ACL Provider – Permit All 

• Advanced Settings 

Advanced Settings 

Advanced Settings include TCP Port (1883), Thread Pool Size, Max Message Bytes and more. 

Users 

Create accounts and set read/subscribe and write/publish privileges to specific topics. 

Retained Messages 

Configure how many retained topics can be stored by the broker. 

Default allows anonymous connections. Modify settings and create users for a secure deployment. 

7. Client Connection Example 

Using Abstract MQTT Driver 

• Connect to the broker using IP and port. 

• Subscribe to topics. 

• Use JSON Toolkit (license required) to parse payloads. 

• More configuration effort. 

Example topic: 

• Topic – ahu/1 

Example payload: 

• Return Temp 

• out – 21.3 

• status – ok 

Using MQTT Service (Recommended) 

• Connect to the broker. 

• Right-click a topic and select Dissect Payload. 

• Select fields and create points automatically. 

• No JSON knowledge required. 

• Fast and easy setup. 

Dissect Payload 

The ahu/1 topic contains: 

• Return Temp 

• out (21.3) 

• status (ok) 

• time (…) 

Create Points 

• Destination Folder – Points 

• Select Create 

8. Performance Considerations 

Monitor your station before adding the broker. Check in Resource Manager. 

Example performance figures: 

• CPU Utilization – approximately 10–15% 

• Heap Free – approximately 190 MB 

• Memory Used – approximately 926 MB of 1 GB 

Heavy loads, many clients or frequent publishing can increase resource usage. Test in your environment. 

Key Takeaway 

• Built-in MQTT Broker Service eliminates the need for external brokers. 

• Easy to configure with strong security options. 

• Supports both secure and non-secure connections. 

• Scalable licensing to suit your needs. 

• Works on any Niagara 4 controller. 

Best Practices 

• Use TLS (1883) and accept certificates. 

• Create user accounts and restrict topic access with ACLs. 

• Limit connections and retained topics according to your controller’s capacity. 

• Monitor performance and busy times. 

• Document your topic structure and client usage. 

Need More Information? 

Download the Tech Bulletin PDF, example stations and training videos from: 

www.tyrrellproducts.com 

The MQTT Broker Service is a powerful, secure and easy-to-use solution for connecting Niagara 4 stations with MQTT devices.