June 2009, Fieldbus & Industrial Networking
Supporters of open building automation standards should themselves remain open as the two main protocols overlap.
Open protocols were conceived as part of an end user backlash against the proprietary building automation and control systems that were traditionally a staple of the market. In the past, if a customer wanted to expand or change their building systems, they were typically locked into using the original supplier of the control system. The rationale for developing open protocols was to prevent this ‘lock-in’ by allowing users the ability to ‘mix and match’ products from different vendors and easily integrate them for management purposes.
Today, most organisations are aligned with one of two key open protocols for automation and control – LonWorks or BACnet. The decision to go down either path can be dependent on a number of factors, for example: the level of integration required in a particular room or zone, the factory-standard controls provided with the building equipment, and future building expansion plans. However, the alignment of the consulting engineer to the project is just as likely to be a key influence.
The trend for open protocols in recent months is one of overlap and convergence. LonWorks, which derives its strength from device-to-device integration, is moving upmarket at a time when open rival, BACnet, known in the high-level system-to-system integration space, is executing a ‘top-down’ approach. The resulting overlap in capabilities means it is now possible for organisations to have a perfectly functional end-to-end automation and control system using either protocol.
Achieving an environment that mixes both protocols, however, is still a fairly complex task. As the overlap in standards becomes more pronounced, the willingness of vendors to support both protocols, either separately or together, will become increasingly important from a future-proofing perspective. The same vendor’s ability to provide systems integration and consultancy support may also prove advantageous in the long term, particularly as the need for integrated LonWorks and BACnet environments increases.
How the standards evolved
LonWorks is the control networking technology platform developed by Echelon Corporation. In 1994, Echelon also created LonMark – a governing body with a set of guidelines and strict testing process to certify the interoperability of LonWorks-based solutions from multiple manufacturers – a critical element to ensure the platform can act as a global open standard. LonWorks is generally considered the best solution for device-level connectivity – for example, enabling the controller that modulates the damper for airflow in a particular room to communicate locally with a lighting controller from another manufacturer.
The American Society for Heating Refrigeration and Air Conditioning Engineers (ASHRAE) developed the other open protocol, BACnet – starting in 1987 and finishing almost a decade later – initially as an enabler for system-to-system integration. The protocol has since evolved to be included in control devices as well. ‘Native BACnet’ solutions are often promoted as the only true open standards by followers, based on the protocol’s development origins from within an ASHRAE industry group as opposed to coming from a private company. The argument does not appear to have negatively affected sales of LonWorks controllers globally, which so far outnumber BACnet-based solutions. In saying that, BACnet can boast a relatively strong following among government and higher education organisations, based on its status as a more openly developed protocol and broad acceptance within the academic and consulting engineer fraternities.
It is currently not possible for LonWorks and BACnet platforms to interoperate without a gateway device that converts one protocol to the other. It is technically possible for either a BACnet or LonWorks device to share a common LonTalk bus to transport messages using their separate control languages (in the same way the devices can communicate over Ethernet) although, in practice, this is rarely done.
Decisive factors for open adoption
As the standards continue to evolve, interoperability is likely to become a key issue. Manufacturers, systems integrators and other professional services firms that remain open to both protocols rather than aligning with either camp will likely have a natural advantage over competitors who do not embrace the relevant standards.
A key factor in any successful building system implementation is a trained and knowledgeable vendor to design the system, write the applications and make the right technology choices to enable efficient operation and maintenance, while accommodating future expansion needs.
While a LonWorks only or BACnet only based solution can work, adherence to a single protocol can create increased complexity and cost, particularly from a long-term maintenance and future expansion perspective.
Emerging standards such as Open Building Information exchange (oBIX) – a protocol for exchanging building information using XML (therefore making it more consistent with Information Technology standards) – further justifies the need to choose a platform with multi-protocol support. These types of solutions will prove far more cost-effective over the life of the building system than those that work with a single protocol.
Making top-tier control accessible
One of the key benefits of open standards is that they have essentially commoditised the automation and control systems market. Cheaper electronics, together with the number of providers with open standards-based solutions, has levelled the playing field both in terms of upfront purchase costs and the functionality manufacturers are able to build into their devices.
While there is little doubt integration and interoperability have improved with the advent of open standards, anecdotal evidence suggests that less than 20% of the commercial building market has embraced the concept to create a true multivendor environment. In reality, up to 80% of organisations – and maybe more – still buy most of their equipment from one vendor. The recent trend away from best-of-breed ‘point’ solution-based environments to end-to-end, single vendor platforms means this trend may continue for some time.
Ultimately open protocol-based devices have benefited the market as a whole. The next challenge – and opportunity – for systems integrators in the space will be ensuring they have the ability to offer either BACnet or LonWorks-based devices or a ‘best of both worlds’ type approach, tailored to the customer’s requirements. At the same time, organisations currently participating in tender processes should ensure the systems integrator or service provider they select has the flexibility to offer multiple control options to ensure the system provided today can scale to meet any future needs in this space.
For more information contact Debbie Rae, Honeywell Southern Africa, +27 (0)11 695 8000, firstname.lastname@example.org, www.honeywell.co.za