Smarten up or risk dumbing down your BMS

Modern integrated controls must have a clear maintenance strategy, says InTandem Systems’ Jon Belfield

Leaps in technology in the past two decades have created the belief that anything is possible with controls. But while products with ever-more sophisticated onboard controls offer the opportunity to increase efficiency and cut energy bills, they also require skilled integration of BMS and intelligent equipment in order that data can be exchanged between systems.

Although lighting, air conditioning, metering and ground source heat pumps (GSHP) can function in isolation, the BMS is the ‘hub’ for a building’s control and management. For example, the BMS needs to know what the air conditioning is doing to avoid simultaneous heating and cooling, and it needs to access the GSHP to maximise its use and only employ boilers/chillers when necessary.

Integration of controls is the responsibility of BMS specialists, who liaise with the suppliers of each system. This ensures that IT protocols and devices are compatible, so the correct data can be shared, without compromise, to any of the connected systems.

The challenge for the supply chain is to work together to deliver the overall system that the client requires. As part of this process, the equipment suppliers – who traditionally provided products that required full control from BMS systems – need to offer technical and field commissioning support for the new intelligent systems.

In the past, for example, air handling units (AHUs) might have been supplied without any controls and so require full BMS control. Now, some come with onboard control systems, and can be integrated simply, via volt-free contacts. A high-level interface is required, however, to get the data onto the BMS, so the client can access it from one point, and plant – such as boilers and pumps – can be enabled to meet any heating demands from the AHU.

Equipment suppliers need to help facilitate the BMS becoming the ‘hub’ for accessing and managing the systems during building operation.

With the focus then moving beyond ‘practical completion’ towards the operational life of a building, there are management challenges, because sustainable support mechanisms for smart buildings are still being worked through.

 Maintenance contracts may be let separately, even though systems share data and devices

Once the building is handed over and occupied, facilities staff must ensure the integrated systems are maintained and supported. This presents anomalies, because maintenance contracts may be let separately, even though systems share data and devices. Routine software and firmware upgrades on one system may have an impact on another system to which it is integrated.

For example, a Bacnet connection was made between the BMS and a packaged GSHP. After routine maintenance on the GSHP – when all the look-up registers were changed during a firmware upgrade – ‘shared’ points held in those registers were no longer visible to the BMS. The GSHP worked correctly, as the points were still visible on that system, but the BMS showed a failure.

In our example, engineers that commissioned the individual systems – with the full understanding of the specific site-integration requirements – were no longer available, meaning the impact of changes across the networked platform were not fully understood.

If a system fails, it may not be an issue with the BMS, but with a shared device on another system, which requires input from a specific system supplier, rather than the BMS specialists. In the example given above, the BMS heating demands were affected because the GSHP data was no longer available. The GSHP supplier needed to supply the new register information so these look-up addresses could be changed within the BMS0.

The supply chain needs to embrace open systems and integration, and have an ‘eyes wide open’ understanding of how the BMS will be managed and maintained. A strategy for supporting the integrated systems should be in place early, before building handover. A single document should define the levels of integration and protocols used, which will enable the occupier to budget for maintenance.

If a combination of companies is required to maintain and support the systems, site-specific relationships should be cultivated between these companies to ensure the right person is deployed to particular issues with the system.

Despite these challenges, such systems offer extensive opportunities for ‘smart’ control of building services – as long as the supply chain works together. In summary, smart integrated buildings need smart integrated support.