Implementing services metering and monitoring networks across large and remote sites is essential to determine accurate service usage figures, apportion energy costs across respective cost centres, and improve the accountability of managers to monitor and maintain the services aspects of their assets.
Until recently the task of implementing such networks was complicated by the cost and complexity issues of installing fixed cabling systems to support them. The alternative of using wireless networks was discounted on the grounds that most wireless networks did not offer the security, robustness and reliability needed for replacing hard- wired telemetry systems.
The introduction of low power wireless technology has effectively addressed these issues, meeting the market need for a cost-effective, standards-based wireless network, to operate in electrically noisy industrial environments; and, typically, for connecting sensors in remote control and monitoring applications.
Based upon the licence- free IEEE802.15, 2.4GHz frequency band, wireless systems such as ZigBee are full- blown telemetry systems in their own right, providing wireless personal area networking (WPAN) i.e. digital radio connections between computers and related devices, such as sensors.
This type of network eliminates the use of physical data buses such as USB and Ethernet cables. It also offers key features, including: acknowledgement that data has been received at its destination; retransmission in the event of failure due to radio collisions or reflections - in a similar manner to TCP/IP networks; validation of message content using data sequence numbering (Frame Check Sequence); network redundancy - such that failure of a node on the network will enable messages to be re- routed via other nodes; and network protocol security encryption.
The power and flexibility of the network is demonstrated by its ability to support over 64,000 devices in star, tree or mesh formations, which form high reliability, self- healing, self-joining networks, with the benefit of network protocol security encryption.
The devices themselves are low powered (via battery) intelligent nodes with onboard metering and logging capabilities. They can be positioned anywhere in or on plant – making system expansion a simple task - gathering data such as energy readings, temperature/flow levels pressures, fault diagnostics and many more.
As the system provides two-way communications, the nodes are able to relay each other’s traffic, bypassing wired networks completely (a problem with other Wi-Fi networks). Moreover, individual nodes offer the flexibility to be interrogated remotely, to determine and change parameters such as temperature, flow, pressure and power (etc).
All of the data gathered from the plant wide networks is sent via Ethernet wireless gateways to be logged in a hosted server. The central web-based server monitors multiple wireless networks with real time viewer and data logging facility. It enables central analysis of the energy used in all areas of distributed facilities, allowing efficiency comparisons and power savings to be calculated.
The economic benefits of this system for the user are many. The fact that more accurate service usage figures are being collected improves accounting charging, reducing costs, removing data errors and increasing the accountability of managers to monitor and maintain the services aspects of their assets. Moreover, the stream of information which can be collected via the wireless system from plant instrumentation across sites is crucial for trending operations to improve on-site demand management and increase efficiency.
About the author: Kevin Buckley
Kevin Buckley is MD of Intelligent Distributed Controls (IDC Ltd), in Derby. The company has a highly skilled team of dedicated hardware and software design, development and application engineers.
These personnel have specialist application knowledge of control systems applied to logistics, warehouse distribution and manufacturing. This applications experience has IDC enabled to develop key skills in real time control, RFID and wireless technology, and to develop niche products for these industries and related OEMs. IDC’s customer base includes Toyota, Toys R Us, ASDA George, Smiths Aerospace, Astra Zeneca and Vestas Wind Systems A/S.
About IDC
Intelligent Distributed Controls (IDC Ltd) is based in Derby. The company has a highly skilled team of dedicated hardware and software design, development and application engineers. These personnel have specialist application knowledge of control systems applied to logistics, warehouse distribution and manufacturing. This applications experience has enabled IDC to develop key skills in real time control, RFID and wireless technology, and to develop niche products for these industries and related OEMs. IDC’s customer base includes Toyota (UK and Europe), Toys-R-Us (UK and Europe), ASDA George, GE Aviation, Astra Zeneca and BAE Systems.
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