In industrial applications, wireless data transmission has been around for a long time. Monitoring temperatures, flow rates, levels and pressure parameters through wireless technology is becoming a popular trend in industrial applications. With the advent of Internet of Things (IoT), wireless sensor networks are deployed in some critical industrial applications. Wireless sensors used in supervisory control and data acquisition (SCADA) effectively address the needs of various industrial applications.
Many companies have been focusing on integrating miniature and low-power wireless radio with sensors. Wireless modules with pressure, flow, and temperature monitoring and control options are being developed to reduce installation and cable costs in large commercial and industrial buildings.
Recent advances in electronics have enabled the roll-out of miniature, low-power and multi-functional sensors that are suitable for short-distance industrial applications. Smart sensors connected through wireless link or wireless sensor network provide unprecedented opportunities for various industrial monitoring and control applications including the environment.
Wireless sensing of acceleration, vibration and velocity provides a more effective way of preventing equipment failures. Wireless sensors are not only wearable but also provide advantages of real-time, continuous, long-distance sensing and ease of operation.
There are many technologies used for wireless data transmission, including mobile phones, Zigbee, GPS, Wi-Fi, satellite, IR, RF and Bluetooth. All industries are different and so are their exact requirements and applications. Hence various standards for sensor connectivity are defined by industrial alliances like HART and Zigbee to meet the requirements of various industrial applications. ZigBee operates at 2.4GHz with data rate of 250kbps. Depending on power output and environmental characteristics, outdoor line-of-sight range of these sensors may be up to 1500 metres. IoT application standards like IEEE 802.15.4 and Narrowband IoT (NB-IoT) enable a wide range of devices and applications.
Industrial applications of wireless sensors
Monitoring machinery and equipment
Wireless sensor networks are deployed to monitor machinery condition-based maintenance. Wireless sensors enable easy access to inaccessible locations, rotating machinery, hazardous or restricted areas, and mobile equipment, which otherwise are difficult to access using wired technology.
Wireless sensors are also employed to collect data for environmental monitoring—for example, monitoring the temperature inside a fridge or monitoring the water level in the overflow tank of a nuclear power plant.
Wireless sensors are suitable for monitoring the quality of underground or surface water and preventing wastage of water. Especially for remote areas having limited infrastructure, wireless sensor networks are ideal as these are fast to deploy and least intrusive for the local environment.
Chemical process monitoring
The concentration distribution of materials during chemical processing can be monitored and controlled using sensors networks. Individual sensor nodes can communicate with other nodes to provide an overall picture of the process. The information may include temperature, pressure, impedance, pH and dissolved gases.
Leading industrial sensor manufacturers
There are many manufacturers in the industrial sensors space, including a few from India. Some major semiconductor manufacturers like Texas Instruments, NXP Semiconductors, Analog Devices, STMicroelectronics and Vishay Intertechnology also manufacture sensors for various industrial applications. Companies like Honeywell International Inc. develop wireless monitoring and control products focused on industrial applications. ROHM Semiconductor offers a broad portfolio of industrial sensors including proximity sensors, light sensors, Hall sensors, capacitive and MEMS sensors. TE Connectivity offers different types of sensors for a wide range of industries including automotive, industrial, medical, appliance and defence.
Plug & Sense devices from Libelium are unique sensors that connect with the most common industrial communication protocols like RS-232, RS-485, Modbus, current loop and CAN bus. These are useful for a wide variety of applications including industrial sensing and automation, military, automobile and remote factory management.
To sum up
Different types of sensors are available for different industrial application requirements. Selecting the right sensor is important for various industrial process control applications. Smart wireless sensors are becoming popular to address various issues in modern industrial applications.