Solve Your BAS Integration Problems Using the Internet of Things (IoT)

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BAS integration of HVAC system retrofits faces a number of practical challenges. Building modernization to combat obsolescence will continue to force the issue.

Today’s BAS integration efforts are hampered by constraints imposed by wired networking. It has been estimated that new wiring costs can make up anywhere from 20% to 80% of the retrofit project costs. This, of course, does not consider the project delays incurred due to the time it takes to scope and install new network wiring.

Many have accepted these exorbitant expenses as a necessary cost of building modernization. That would be incorrect. IoT has injected new life into traditional BAS integration projects, simplifying project complexity and providing critical flexibility in addressing a wide range of retrofit scenarios.

The Cloud Has Removed Limitations Imposed by On-Site Networking

Traditional integration of an I/O module with a BAS requires a series of network links from the BAS to the I/O module location. For wired networks, network cabling would need to be installed to ensure a contiguous network path that extends from the BAS to the I/O module. For example, RS-485 network wiring can be installed between a gateway device and a Modbus I/O module location.

Wireless I/O modules do not alter the fundamental requirement of on-site networking. For wireless I/O modules, a wireless network link (e.g., Zigbee) would simply replace a network cable as the wireless I/O module connects to a wireless gateway device. A conventional wired network from the wireless gateway device to the BAS would then complete the integration of the wireless I/O module.

In either case, conventional on-site networking topology would be preserved.

IoT I/O modules break the networking restrictions of this framework. IoT I/O modules would connect to an off-site cloud core either directly or through an intermediary gateway device. From the cloud, connectivity to the BAS can be implemented at any point in the BAS network.

Consider, for example, an IoT thermostat installed in a remote part of a building or campus. The IoT thermostat would establish a WAN connection to the cloud for delivery of sensor data (e.g., Temperature, Humidity, CO2, etc.) and for receipt of control commands (e.g., setpoint changes). The cloud can then present a virtual I/O interface of the IoT thermostat to a centralized BAS at any part of the network in that building, or even in another building. This would obviate the need for potentially complex on-site networking using wired and/or wireless network links.

IoT Brings Scalability to BAS Integration Projects

IoT is renowned for simplicity. IoT edge devices typically feature tight integration with the cloud OS, thereby ensuring real-time data visualization in the cloud with zero-touch on-site configuration. IoT removes the complexity of adding new I/O modules to a building’s sensor infrastructure. Do you want Indoor Air Quality (IAQ) data from a conference room? Simply, attach a wireless IAQ module to the wall, turn it on, and see real-time visualizations of the IAQ metrics in the cloud within minutes. It is that easy.

Once the additional I/O modules have established a connection to the cloud, the entire set of additional I/O modules can be integrated into the BAS at a single virtual I/O interface. For example, assume that five different IoT thermostats were installed at scattered locations within a building. A single virtual I/O interface can be used to present the five different IoT thermostats to the existing BAS for integration.

BAS programming for a single gateway that presents a virtual I/O interface would deliver scalability and predictability to the entire integration project. Removing project complexity will inevitably eliminate BAS integration project delays.

IoT Reduces the Dependence on Wireless Networking Standards

The presentation of a single virtual I/O interface to a BAS has broad implications. From the perspective of the BAS, that single I/O interface is the only interface that matters. If the BAS supports the standardized BACnet protocol, then the single I/O interface can be presented via a virtual gateway using BACnet.

Significantly, the communication protocols used for the IoT I/O modules becomes insignificant to the BAS. Effectively, the cloud would perform the protocol conversion such that virtualized representations of the IoT I/O modules are presented to the BAS using whatever protocols the BAS supports (e.g., BACnet). In and of itself, the BAS would not be dependent on any particular wireless networking standard. Any communication protocol or multiple communication protocols can be used to connect the various IoT I/O modules to the cloud. Once connected to the cloud, the virtualized I/O module can be presented to the BAS using the supported BAS interface.

Moreover, should the BAS be upgraded in the future, the entire set of virtualized I/O modules can be presented to the upgraded BAS using a new protocol supported by the upgraded BAS. Modification or replacement of the IoT I/O modules would not be necessary.

The cloud obviates the need for a myriad of hardware protocol conversion products. The cloud itself can effectively perform all necessary protocol conversions to ensure maximum compatibility between legacy, proprietary and standardized protocols.


Building modernization efforts will continue to increase as building owners and operators increasingly compete to satisfy demands of potential tenants. BAS integration projects will form part of that solution. Cloud-based IoT solutions can radically simplify the complexity of the much-needed BAS integrations.

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