RELATED APPLICATIONS

This application is related to U.S. patent application Ser. No. 16/806,895, titled Device and Method for Managing Communications, by Vijaykumar Santhakumar, et al., filed on Mar. 2, 2020, and incorporated by reference in its entirety.

FIELD OF THE INVENTION

This application relates to the field of building management systems and, more particularly, to a sensor device of a building management system for managing multiple wireless communications.

BACKGROUND

Building management systems encompass a wide variety of devices that aid in the monitoring and control of various aspects of building operation. Building management systems (which may also be referred to herein as “building automation systems”) include security systems, fire safety systems, lighting systems, and heating, ventilation, and air conditioning (“HVAC”) systems. Lighting systems and HVAC systems are sometimes referred to as “environmental control systems” because they are capable of controlling the environmental conditions within the building.

The elements of a building management system may be dispersed throughout a facility. For example, an HVAC system includes temperature sensors and ventilation damper controls as well as other elements that are located in virtually every area of the facility. Similarly, a security system includes intrusion detection, motion sensors and alarm actuators dispersed throughout an entire building, and a fire safety system includes smoke alarms and pull stations dispersed throughout the facility. The different areas of a building management system may have different environmental settings based upon the use and personal likes of people in those areas, so the devices of a system frequently communicate with each other and proximal devices in order to determine optimal environmental settings.

The devices of a building management system are becoming technologically complex while distribution and installation of such devices needs to be as easy as possible. Many devices include multiple sensor and/or communication components that are packaged within a simple housing. The design of these devices, packing many features into a small form factor, can be challenging due to the potential interference and sensitivity of different communication technologies, each trying to maximize their performance and area of coverage.

SUMMARY

In accordance with some embodiments of the disclosure, there is provided a communication management approach for field devices of building management systems. A building management system may include field devices that integrate sensors with multiple sensors or, more particularly, a motion sensor with one or more radio frequency (RF) sensors. For example, a lighting device may include a passive infrared sensor to detect motion and RF sensors to transmit and/or receive wireless signals. Each RF sensor may utilize an antenna to optimize communication such as a Bluetooth (BLE) antenna, an IEEE 802.15.4 antenna, and/or an ultrawide band (UWB) antenna. The RF antennas may be positioned strategically about, and offset from, the sensor in order to maximize performance while integrating with the motion sensor within a small form factor. Also, a shielding may be strategically positioned at fixed lengths from each antenna to enhance the ability of the corresponding sensor to focus on an area of interest and improve its range of communication. For some embodiments, the shielding may operate in coordination with other components, such as the outer surface of the sensor or parts of the housing, to act as a Faraday-like cage or shield to enhance performance.

The circuit board of the field device, or more particularly an edge of the circuit board (as opposed to the planar surface on either side), is positioned adjacent the sensor such that the circuit board extends beyond the backend of the sensor, i.e., the end opposite the frontend. Antennas of the RF sensors are coupled to the circuit board and, likewise, both shields are grounded to the circuit board. The wireless signals communicating with the antennas are focused on the field of view in front of the sensor, i.e., the area where moving objects are expected to exist.

The building management system may include field devices that switch between different sensors or antennas, in which one sensor or antenna may be focused in a first direction and a second sensor or antenna may focus in a second direction different from the first direction. For example, a circuit of the circuit board may switch between the antennas on-the-fly based on packet error rate (PER) associated with the performance of the antennas. For some embodiments, the field device may include a third antenna in which the second antenna may operate as shielding for the third antenna, particularly when the second antenna is not radiating.

One aspect is a device for switching communications comprising a circuit board as well as first, second, and third antennas. The first antenna is coupled to the circuit board, and the first antenna is focused on a first direction and based on a first wireless technology. The second antenna is coupled to the circuit board, and the second antenna is focused on a second direction and based on the first wireless technology, in which the second direction is different from the first direction. The third antenna is coupled to the circuit board, and the third antenna is focused on a third direction and based on a second wireless technology, in which the second wireless technology is different from the first wireless technology. The second antenna may operate as a shield for the third antenna.

Another aspect is a method of a device for switching communications. A circuit may control operation of a first antenna, a second antenna, and a third antenna. The circuit may switch operation of the first wireless technology between the first antenna to the second antenna based on a performance of the first and second antennas. The circuit may switch operation of the second antenna between an active operation state and a passive ground state. The circuit may maintain the second antenna in the passive ground state when operating the third antenna.

The above described features and advantages, as well as others, will become more readily apparent to those of ordinary skill in the art by reference to the following detailed description and accompanying drawings. While it would be desirable to provide one or more of these or other advantageous features, the teachings disclosed herein extend to those embodiments which fall within the scope of the appended claims, regardless of whether they accomplish one or more of the above-mentioned advantages.

