Wireless sensor networks in industrial automation

Wireless communication technologies are being adopted in every possible domain of applications. With their benefits of easy deployment and mobile connectivity, they are making their way to plant-floors also. Wireless networks are being implemented at sensor level as well as at control level, replacing the existing current loops, sensor-level networks and FieldBuses. While doing so, they have to satisfy the real-time requirements of the replaced FieldBuses, because different process control applications require different types of data buses with varied throughput, latency and ruggedness. In addition to these specifics, it has to deal with electromagnetic interference (EMI), which is omni-present on plant-floors. In this context, some automation suppliers and transducer manufacturers are offering wireless solutions conforming to standards like Wi-Fi, BlueTooth, ZigBee etc, while others are rolling out proprietary solutions suitable to specific applications. With different technologies and products offered by different vendors, interoperability is often a challenge, and there are attempts from standards organizations like IEC/ISO and major automation vendors to role out some standards and conform the products to them. A discussion of different wireless technologies, which can be implemented at senor and control levels, the problems associated with them and the suitability of them to different applications is presented in this paper.