How to Create a BACnet Specification

In a webinar, experts from ICONAG Leittechnik explained the functionality and advantages of the BACnet specification. The presenters provided an overview of BACnet standardizations and regulations. While existing standards such as ANSI/ASHRAE Standard 135-2020, ISO 16484-5, BTL Certification, and AMEV BACnet 2017 offer solid foundations, they also reveal critical gaps. Additionally, many requirements must be formulated on a company- or project-specific basis.

From a management-level perspective, certain specifications must be defined in the BACnet specification document.

"Particularly in areas such as networking/addressing, object identification, BACnet alarming, BACnet scheduling, and BACnet trending, specific BACnet object requirements must be clearly defined," explains Daniel Rörich, an expert at ICONAG specializing in BACnet specifications.

"Additionally, the COV (Change of Value) threshold values should be established. We recommend creating a matrix for this purpose."

This matrix defines the required change thresholds for specific requirements, which trigger the reporting of a new value in analog objects.

Another important aspect is priority control. For priority-based writing, standard write priorities should be defined, along with exceptions that deviate from these standards.

A useful document during the construction phase is the BACnet EDE file, which allows for verification of BACnet project planning even before a device is connected to the MBE (Management and Control System).

Practical Insights from ICONAG Experts

The ICONAG experts share insights from their extensive experience in creating and maintaining BACnet specifications.

"The time commitment, in particular, should not be underestimated," emphasizes Daniel Rörich.

"From drafting a BACnet specification on a blank page, coordinating topics with customers and internally within the company, to finalizing the first version, the process takes at least six months."

When creating a BACnet specification for a client, the development process should be divided into manageable sections, with each section being reviewed and discussed before and after with the client.

A BACnet Specification is Never "Finished"

"A specification is never truly completed," Rörich explains.

Ongoing developments in the BACnet protocol and changing company requirements necessitate regular updates.

He also emphasizes that a BACnet specification alone is not a universal solution.

It does not solve all problems in building automation (GA) but should be seen as part of an overall GA specification.

Other critical topics for defining clear requirements include:

• User Addressing Systems
• Implementation of MSR Functions (Measurement, Control, and Regulation Technology)
• Defining Automation Focus Areas

"It is also crucial to keep an eye on the development of AMEV BACtwin," Rörich notes.

"Many future requirements will be standardized through the AMEV BACtwin concept—for example, specifying which objects and properties should be used for which systems and equipment."

More Information

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