Wireless Tech for Remote Valve Monitoring

Remote Automated Control and Monitoring Reduces Valve Maintenance Issues

By Dan Hebert

Your process plant probably contains hundreds if not thousands of control, automated on/off and manual valves. Odds are that these valves are one of your main maintenance headaches because, unlike most other automation components, they contain moving parts and are thus prone to failure.  One of the best ways to reduce valve maintenance issues is through remote automated control and monitoring, using both wired and wireless technology. Wired connections between valve actuators and positioners and plant automation systems are a proven method for control and monitoring. But many existing valves don't have wired connections to the automation system, and installing these wires can be prohibitively expensive. The same is true for valves that are upgraded or retrofitted into existing process areas. In either case, wireless valve actuation and monitoring can be the best solution.

So, what's the best way to wirelessly control and monitor a valve? Ira Sharp, product marketing manager for I/O and networking at Phoenix Contact, says, "WirelessHART is ideal for short distance (generally less than 500 ft) networks for sensors because it uses a mesh network that can expand with each node being a repeater for every other node in the network. Bluetooth works well for short-distance (less than 500 ft) cable replacement of sensor cables or serial/Ethernet cables."

Sharps adds, "WLAN is good for medium-distance (1000 ft to 3000 ft), high-bandwidth applications, such as video surveillance. Our Trusted Wireless and other proprietary networks are suited for long-distance (up to 20 miles) SCADA applications. UHF is ideal for very long-distance (up to 40 miles) SCADA, and cellular is the best choice for applications where private radio will not work, such as very remote areas or mobile applications."  

Ninety percent of users have an annual experience where a manual valve is the wrong position due to human error.

Of the technologies mentioned, WirelessHART is perhaps the market leader. "Since WirelessHART is HART technology, it is simple to install and use, making implementation fast and low-risk," claims Chuck Micallef, marketing consultant at the HART Communication Foundation. "The key is to have an asset management or device monitoring application that will provide user access to the diagnostic information already in the HART-enabled valve positioner. A WirelessHART adapter can be added to any HART-enabled positioner, existing or new, extending the benefit of the installed asset," adds Micallef.

"A typical plant has 15% control valves, 25% automated on/off valves, and 60% manual valves," notes Dan Carlson, specialist for wireless sales at the Fisher division of Emerson Process Management. "The best solution for control valves is the application of adapters that access local diagnostics in the valve controller, and relay it to remote monitoring systems."

"Ninety percent of users have an annual experience where a manual valve is in the wrong position due to human error—resulting in a bad batch, environmental release or safety incident. WirelessHART manual valve position feedback can be incorporated into digital interlocks, or a WirelessHART on/off controller can upgrade the manual valve to automatic."

"Wireless valve actuators and positioners generally make use of low-power IEEE 802.15.x radios, using a combination of proprietary and open protocols with varying levels of interoperability," says Paul Brooks, business development manager at Rockwell Automation

Expect to see more and more wireless remote monitoring as time goes on. "Over the coming years, we expect the open standards Wireless HART and ISA100.11a to dominate—allowing a single wireless and asset management solution for instrumentation, actuators and positioners. Don't count out WiFi either. As companies extend their WiFi networks, and as suppliers add WiFi capabilities to their actuators, this technology may become more pervasive," says Brooks. 

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  • <p>I agree that valves require more attention for daily maintenance and at turnarounds than a lot of the instrumentation. Valves are in direct contact with the process; which has extreme temperatures, pressure drops, vibration, corrosion, and erosion etc.</p> <p>I also agree both wired digital networking (fieldbus) and wireless networking such as WirelessHART can be used to reduce maintenance.</p> <p>And I also agree that laying new cable in an existing plant is not only prohibitively expensive, but may be prohibitively risky as you may damage your existing installation when opening cable trays and rewiring in junction boxes. Thus is personally see FOUNDATION fieldbus as ideal for building new plants since fieldbus positioners come with position feedback and diagnostics built-in from the very beginning, and WirelessHART as ideal for modernizing existing plants. Note that this is possible for both throttling/continuous valves as well as on/off valves, both linear and rotary motion.</p> <p>WirelessHART is by no means limited to 150 m (500 ft). Any IEEE 802.15.4 radio like in WirelessHART devices can reach 250 m or more in a single “hop” if the right conditions apply; no obstructions and line of sight. However, such ideal conditions hardly ever apply within a plant full of metal: structural steel, pipes, and vessels. In a plant environment, the distance for a “hop” can be limited to as little as 50 m or less due to the impenetrable obstacles. This applies the same to all protocols. In a plant environment you need full mesh topology capable of multiple hops; 7 or more, so that the data can work its way around obstacles until it reaches the gateway. </p> <p>Therefore, I would rather say that WirelessHART is ideal within a dense plant environment thanks to the full multi-hop mesh eliminating the need for multiple wired backbone routers to be installed inside the plant unit.</p> <p>I use Bluetooth for mouse, keyboard, mobile phone, and headset – for which is works great. I would not apply it to industrial gear.</p> <p>I agree that existing plants should upgrade to smart valve positioners if they don’t already use them. If the control system doesn’t have I/O cards with HART “pass-through” to Intelligent Device Management (IDM) software part of the asset management system (AMS), which is most often the case, then these positioners should be fitted with WirelessHART adapters. This enables the IDM software to access the valve diagnostics. This way you can better plain daily maintenance and turnaround for valves; to know which valves you need to rip and tear down and which ones you don’t – improving what I like to call “time on pipe”. The maintenance and turnaround work processes for the plant should be rewritten to make use of this valve diagnostics. Learn more about valve diagnostics and other device diagnostics from the diagnostics tutorial and work process guide found here: <a href="http://www.eddl.org/DeviceManagement/Pages/DeviceDiagnostics.aspx">http://www.eddl.org/DeviceManagement/Pages/DeviceDiagnostics.aspx</a></p> <p>Wireless position feedback on hand operated valves is important. Start installing WirelessHART position transmitters on the bypass valves used at shutdown valve stroke testing. If such a bypass valve is left open would be very serious, so monitoring such bypass valves is important. Next, put WirelessHART position transmitters on other manual valves used in day to day operation. If you are building a new plant, use FOUNDATION fieldbus not only for control valves, but also for on/off valves and electric actuators. Intelligent two-wire on/off valves reduce wiring, provide feedback, and diagnostics over the same two wires.</p> <p>Since there is an international standard since many years ago; IEC 62591 (WirelessHART), I would not use any proprietary wireless protocols for valve diagnostics, valve monitoring, or other applications.</p> <p>Activation of relief valves is a related area. It could use either acoustic transmitter or position transmitter. Feedback from shutdown valves is also useful.</p> <p>A beauty of WirelessHART is that you don’t need to have multiple different networks for control valve diagnostics, position feedback, and relief valve monitoring and tons of other applications. A single WirelessHART gateway handles these applications and many more for the entire plant unit. </p>


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