Wireless Sensor Technology Overview:
In a market characterized by great fragmentation, it is crucial that users carefully evaluate which wireless technology best suits their needs. Although Wireless Sensor Networks (WSNs) have collectively garnered much attention, differences in technologies and respective implementations from different vendors are quite significant. Many systems on the market today are silo solutions that, although compelling for specific applications, aren’t suited for all situations. Wireless Sensors has recognized this shortcoming, and therefore architected a framework to provide broader applicability and to keep pace with technology evolution as the industry continues to grow.
Due to its ability to support not only sensing but also actuation our technology is best categorized as a Wireless Device Network (WDN). Strengths and competitive advantages include:
Standards-based:
Our RF technology relies on the proven IEEE 802.15.4 physical layer and MAC. IEEE 802.15.4 is uniquely designed for low-rate and low-cost wireless communications, and offers better power efficiency than WLAN or Bluetooth radios. Higher layer networking functions are defined by standards such as WirelessHART and 6LoWPAN, which are built on top of IEEE 802.15.4. Wireless Sensors is compatible with both, and our implementation is forward-compatible with WirelessHART.
Ultra-low power:
Extended operation on battery power or the use of energy scavenging is a key requirement in the deployment of wireless device networks. Wireless Sensors utilizes a precise time synchronization algorithm, allowing all nodes to remain in standby mode when not required to perform a measurement or wireless transaction. In standby mode, nodes can operate on extremely low amounts of current since most hardware components are powered off. As a result, overall power consumption is dramatically reduced and largely correlated with the desired sample rate, rather than unnecessarily drained by idle states.
Bounded communication latency:
A secondary benefit of the time synchronization approach is its ability to provide balanced medium access and predictable transmission slots. This keeps latency within tolerable limits, enabling real-time monitoring of assets and guaranteed delivery of time-critical information such as alarms and control commands.
True mesh networking:
The self-organizing and self-healing properties provide maximum fault tolerance and deployment flexibility. Sensor nodes establish connections and transmission paths by themselves, and are capable of multi-hop routing for formation of arbitrary topologies and bridging of extended distances. In contrast to ZigBee, Wirerless Sensors routing nodes do not depend on line power and can run on batteries making them particularly suitable for environments where hardwiring would be difficult or prohibitively expensive.
Robust and secure transmissions:
For maximum reliability, Wireless Sensors employs automatic retries, acknowledgements, and a channel hopping scheme. Network security is provided through encryption of all data transmissions, and each individual data packet is integrity protected. In addition, join requests by new nodes can be authenticated via access control list so that only known and legitimate nodes are granted access, based on their unique MAC address.
Field device and fieldbus connectivity:
Sensors accept 0-20 mA, 4-20 mA, 0-2 V, 0-10 V analog, PT100, pulse, and digital inputs from field devices or meters. Seamless integration with fieldbus and management systems is provided through serial, Ethernet, Profibus, Modbus, CAN, and GPRS gateway interfaces.