Contemporary Controls offers two BASstat — BACnet-networked communicating thermostat models that provide customers with flexibility when installing a distributed zone thermostat control system. Depending on parameters such as building zone layout, existing EIA-485 cabling, Wi-Fi routers in place, and connection distance requirements between BASstat thermostats and BASview3 supervisory device, each BASstat model offers distinct benefits for convenience of installation.
The BASview3 is the centralized BACnet supervisory device of the entire system communicating to the routed thermostats using the BACnet/IP protocol over a wired Ethernet connection. Depending on the requirements of the installation, a wired or Wi-Fi thermostat model can be chosen. A BASrouter BACnet MS/TP to BACnet/IP router or a Wi-Fi to Ethernet router are required to complete thermostat integration to the BASview3 supervisor.
The BASRT-B router is used to convert BACnet MS/TP serial connection from several (up to 31) BAST-221C-B2 wired (EIA-485) thermostats on the same bus to BACnet/IP over Ethernet connection to the BASview3 supervisor.
A Wi-Fi router is used to route the wireless signal from several BAST-221C-BW2 (number of Wi-Fi clients depends on distance and Wi-Fi router performance) wireless thermostats to Ethernet carrying BACnet/IP messages to the BASview3 supervisor.
Thermostat Connection Using BACnet MS/TP over EIA-485
The BAST-221C-B2 wired thermostat model is BACnet MS/TP connected utilizing an EIA-485 serial connection. The EIA-485 physical layer can be very effective. It offers the flexibility and convenience of a maximum segment distance of up to 1200 m /4000 ft. allowing for daisy-chaining of equipment on the same bus making it the perfect choice when long segment lengths are required for the installation or when there is an existing EIA-485 infrastructure in place. Communicating at lower speeds also gives it the advantage of being more resilient to the noise present in harsh or industrial environments. EIA-485 wiring can be found in many existing buildings making it perfect for retrofit upgrades without the need to run new wires. The BAST-221C-B2 thermostat can be connected to a BACnet MS/TP to BACnet/IP router such as the BASRT-B which routes the BACnet MS/TP traffic to BACnet/IP to the BASview3 supervisor.
Thermostat Connection Using BACnet/IP over wireless Wi-Fi connection
The BAST-221C-BW2 wireless thermostat model is BACnet/IP connected using a wireless connection to a nearby Wi-Fi router/access point which supports IEEE 802.11b/g/n. The respective maximum indoor range is 115 ft. for IEEE 802.11b, 125 ft. for IEEE 802.11g, and 225 ft. for IEEE 802.11n considering there are little to no substantial obstructions between the Wi-Fi router and the thermostats which is the case in most standard buildings. Some building materials rarely found in standard buildings can create obstructions which prevent Wi-Fi radios from communicating such as thick reinforced concrete (at least 200mm with or without metal reinforcement), thick masonry blocks and brick-faced walls, and metal obstructions such as shelving units or dense metal reinforcements. However, most widely used materials such as standard concrete or brick walls (100mm), lumber, plywood, and glass do not impose serious Wi-Fi radio barriers making Wi-Fi a convenient choice for many installations where wireless Wi-Fi communication can be conveniently leveraged to avoid running wires.
In addition, there are free Wi-Fi signal measuring tools such as Vistumbler for Windows PC/laptop of Wi-Fi Analyzer app for Android mobile devices which can be helpful to ensure a resilient Wi-Fi connection between the thermostat and the Wi-Fi router/access point. These free tools can be installed on a laptop PC/tablet or a mobile device. Simply connect it to the Wi-Fi router/access point, measure its signal strength by moving the laptop or mobile device away from it to the location where the Wi-Fi wireless thermostat host would be installed, and monitor the signal strength graph in the tool. Wait a couple of minutes to ensure the signal is stable and sufficient. The Wi-Fi tool will scan for nearby wireless networks and give you a comprehensive report including the name, signal strength, kind of encryption, MAC address, channel the network is using, manufacturer, and more. It will also graph the traffic for each network. The performance of the Wi-Fi router determines how many Wi-Fi clients such as the BASstat Wi-Fi thermostat can connect to it at a time. Caution must be used if the same Wi-Fi router is used for IT networking and Internet access of zone occupants. It is not absolutely necessary, but one option is to create a VLAN to isolate the IT network from the OT network which is a feature available in most modern Wi-Fi routers. The Wi-Fi router/access point is used to route the wireless signal from the thermostat carrying BACnet/IP messages to wired Ethernet and effectively to the BASview3 supervisor.
BASview3 BACnet Supervisor
The BASview3 is a stand-alone, embedded, web-based graphical interface for building automation and process automation systems. It can be accessed from any web browser – providing supervisory functionality to any BACnet/IP system. The BASview3 is easy to install and intuitive to use – it requires no license, no training, and no external tools. The BASview3 is housed in a DIN rail mounted metal enclosure and it is 24VAC/VDC powered for convenient installation. A 10/100 Mbps Ethernet connection is all that is needed for communication. Supervisory features include animated graphic screens, scheduling, historical trending, runtime accumulation and email alarms. BASview3 will automatically toggle outputs and change set points on schedule, collect run time and trend data, and monitor alarm conditions.
BASview3 supports multiple logins with different user permission levels allowing you to create dashboards and/or graphics for both the service personnel which provide maintenance to the HVAC equipment, as well as the end users/occupants who are interested in comfort parameters such as current temperature and state of operation such as heat/cool/ventilate HVAC modes. Different user permission levels also allow some users to log in and modify (write) parameters such as set points for building maintenance and control staff, or only allow viewing (read) of these parameters for other users such as occupants.
BASview3 Graphic example
Graphics differentiate from dashboards because you can upload images (PNG, GIF) such as floor plans, mechanical equipment, zone layout, actual picture of a zone/room, etc. to the BASview3 and then freely position animated graphical elements such as gauges, buttons, labels, charts, etc. on top of the image which give insight to users about zone temperature, zone set point, etc. and some control such as adjusting a set point or changing occupancy state.
BASview3 Dashboard Example
Dashboards differentiate from graphics. In a dashboard, users cannot upload or freely position images but rather graphical elements such as gauges, charts, trend graphs, buttons, labels, icons are placed in containers and positioned on the screen. This makes them scalable across devices such as tablets and smart phones as well as PC monitors. This is ideal for monitoring and controlling equipment over the BACnet network. A library of widgets and visual elements is provided as seen in the example above.