Ensuring Interoperability: BIBBs, Profiles, and PICS

Imagine walking into a hardware store and buying a lamp from one manufacturer and a light bulb from another—you expect them to work together. Now imagine a smart building with a thermostat from Honeywell, lights from Philips, and a security system from Johnson Controls. For them to work together seamlessly, they need a guarantee of interoperability. BACnet provides this guarantee through three key mechanisms: BIBBs, Profiles, and PICS.

In this article, we’ll clarify how BACnet ensures interoperability between different vendors’ devices. We’ll explain BACnet Interoperability Building Blocks (BIBBs), standard Device Profiles, and the critical role of the Protocol Implementation Conformance Statement (PICS) document.

What is Interoperability?

First, let’s define the term. Interoperability means that devices from different manufacturers can communicate and work together without custom integration or special programming. It’s like speaking a common language—if two people speak the same language, they can understand each other.

For building automation, interoperability is essential because:

It enables centralized control of all building systems

The Three Pillars of BACnet Interoperability

BACnet ensures interoperability through three interconnected mechanisms, working together like a construction team building a house:

1. BIBBs: The individual “bricks” that make up interoperability

2. Profiles: The “blueprints” that define device capabilities

3. PICS: The “inspection report” that verifies compliance

Let’s explore each pillar in detail.

1. BIBBs: BACnet Interoperability Building Blocks

BIBBs are the basic building blocks of BACnet interoperability. They define specific communication capabilities that BACnet devices must support to work together.

What Are BIBBs?

Think of BIBBs as individual “skills” that devices can have. For example:

Both devices would need a “Discover Devices” BIBB to find each other

How BIBBs Work

Each BIBB consists of two parts:

Server Part: The ability to respond to a service (e.g., “My temperature is 72°F”)

Devices can implement just the client part, just the server part, or both, depending on their role.

Common BIBBs

| BIBB Name | Purpose | Example Use |

|—————|————-|—————–|

| ReadProperty | Read a device property | Thermostat reads temperature from a sensor |

| WriteProperty | Write to a device property | Building manager sets a temperature setpoint |

| Who-Is/I-Am | Device discovery | New device announces itself to the network |

| Alarm-Notify | Send alarm notifications | Fire panel alerts the HVAC system to shut down |

| TrendLog | Log historical data | Energy management system logs power usage |

Why BIBBs Matter

They enable clear compatibility checking (you can verify if Device A has the BIBBs that Device B needs)

2. Profiles: Standardized Device Blueprints

If BIBBs are individual bricks, Profiles are the blueprints that specify which bricks to use for a particular type of device. Profiles define a standard set of BIBBs that devices must implement to be considered compatible.

What Are Profiles?

Profiles are pre-defined sets of BIBBs for common device types. They ensure that, for example, all “BACnet Advanced Application Controllers” have the same basic capabilities.

Common BACnet Profiles

|——————|——————|—————-|—————|

Benefits of Profiles

Easier Maintenance: Technicians can work on any profile-compliant device without special training

Example: How Profiles Work

If you’re looking for a new thermostat, you can specify that it must comply with the B-AAC profile. This guarantees it will support all the BIBBs your building system needs, regardless of the manufacturer.

3. PICS: Proof of Compliance

The Protocol Implementation Conformance Statement (PICS) is a document that manufacturers provide to prove their devices comply with BACnet standards.

What Is a PICS Document?

Think of a PICS as a device’s “resume”—it lists all the BIBBs and profiles the device implements, along with other technical details.

What’s in a PICS Document?

A typical PICS includes:

Special Features: Any optional features implemented

How to Use PICS Documents

1. Selection: When choosing a new device, compare its PICS with your system requirements

2. Integration: Use the PICS to understand how the device will communicate with your existing system

3. Verification: Use the PICS to verify that the device supports the BIBBs and profiles you need

4. Troubleshooting: Use the PICS to understand what the device should be able to do when debugging issues

Example: Checking a PICS

Suppose you need a device that can write to temperature setpoints. You’d look at its PICS to verify it implements the client part of the WriteProperty BIBB for Analog Output objects.

Putting It All Together: How BIBBs, Profiles, and PICS Work Together

Let’s see how these three mechanisms work together in a real building scenario:

Scenario: A building manager wants to add a new thermostat to their BACnet system, which currently has lighting from Company A, HVAC from Company B, and a security system from Company C.

Step 1: Check System Requirements

It needs the thermostat to support scheduling, temperature reading, and setpoint writing

Step 2: Choose a Profile

The manager selects the B-AAC profile, which includes all required BIBBs

Step 3: Verify Device Compliance

It also confirms it works over BACnet/IP

Step 4: Install and Configure

No custom programming is needed

Benefits of the BACnet Interoperability System

For Building Owners

Future-Proofing: Can easily add or replace devices without overhauling the entire system

For System Integrators

Faster Installation: Less time spent troubleshooting integration issues

For Manufacturers

Reduced Support Costs: Standardized functionality means fewer support calls

How BACnet Interoperability Is Tested

To ensure devices actually work as advertised, BACnet has a rigorous testing process:

1. Laboratory Testing: Devices are tested at authorized BACnet Testing Laboratories (BTLs)

2. Profile Compliance: Devices are tested against their claimed profiles

3. Interoperability Testing: Devices are tested with equipment from other manufacturers

4. Certification: Passing devices receive the BACnet Tested Mark

Conclusion: Interoperability Made Simple

BACnet’s interoperability system—BIBBs, Profiles, and PICS—provides a clear, standardized way to ensure devices from different manufacturers work together seamlessly. BIBBs define individual capabilities, Profiles create standardized device types, and PICS verify compliance.

This system is like a universal language for building automation, ensuring that devices can communicate regardless of who made them. It gives building owners freedom of choice, reduces costs, and future-proofs building systems.

So the next time you see a BACnet device with the BTL mark, you can be confident it will work with your existing system—just like that lamp and light bulb from different manufacturers work together perfectly.