11242017Fri
Last updateWed, 22 Nov 2017 2pm

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Monitoring Valve Health via the Internet

Most valve end users are already using smart valve positioners on some control valves, but they may not have time to check the valve diagnostics software to notice if any valves are developing problems. Imagine instead simply getting a weekly report listing which valves need attention.

The Industrial Internet of Things (IIoT) enables valve experts at corporate engineering or company expertise centers to monitor the health of the valves in a plant remotely to drive better valve performance over the lifespan of those valves. Related equipment such as pumps also can be monitored.

IIoT is just starting to be a catch-phrase, and those considering its use are often left wondering how to get started. Many plants have chosen a phased approach to implementation, starting within the plant, then connecting to the internet much later.


17 sum IIOT Fig1

 

PHASED APPROACH

Some plants already use digital networking at the field instrument level. Those that bring the data across the internet to a center of operations are deriving the benefits of IIoT. However, most plants are not yet there. For these plants a step-by-step solution for deploying IIoT may be a good solution (Figure 1).

The first several steps do not connect to the internet, which means the instrumentation and controls (I&C) department can launch an initiative right away. The information technology (IT) department gets involved later, when access across the internet is implemented.

17 sum IIOT Fig2Step 1: Plant-wide Digital Field Communications Networks

Some of the many plants that already use smart valve positioners are digitally integrating them with intelligent device management (IDM) software for centralized control valve diagnostics. Modern plants built with a control system that has digital fieldbus communication networking to integrate instrumentation typically use intelligent valve positioners.

Control systems based on 4-20 mA that do not support the HART communication protocol require the instrument engineer to bring a laptop with a modem into the field to perform valve diagnostics, which hampers valve management. Deploying HART multiplexers would be costly and could damage existing marshalling cabinets.

Adding wireless sensors and integrating them with the existing control system makes the plant more efficient and reliable by covering measurements left out of the original design. This proves the technology works.

By installing wireless adapters on smart valve positioners, the valve diagnostics also can be accessed across the wireless field network (while control still uses the real-time analog 4-20 mA signal). Modern plants built on fieldbus allow easy connection of additional sensors but also deploy wireless sensor networks.

Some equipment data is collected manually, which encumbers condition monitoring and energy management. Yet deploying 4-20 mA transmitters would be expensive and could damage existing cable.

A good place to start the process of stages is by deploying WirelessHART (IEC 62591) networks in each plant unit. Using the correct protocols, gateways connect to the distributed control system (DCS), historian and condition monitoring software.

The IIoT solution must be an extension that is backwards-compatible with the existing networks in the plant. Fieldbus and wireless instruments form the base layer for the IIoT.

Once the WirelessHART network is deployed, sensors that will meet the needs of departments that deal with reliability; maintenance; energy efficiency; operations; health, safety and environment (HS&E); and integrity can follow.

17 sum IIOT Fig3Step 2: Instrumenting Assets

If a plant is using fieldbus, the valve positioners are already intelligent, and sensors for condition monitoring of other equipment can be added easily to the same fieldbus networks. If a plant is built on 4-20 mA and on-off signals, valve positioners may not be smart. A good step forward is to modernize all control valves with smart valve positioners, starting with the most critical valves (Figure 2).

Sometimes smart valve positioners were not deployed in the past because the control system did not support HART communication pass-through. This is no longer an issue because smart valve positioners fitted with a wireless adapter send data to valve diagnostics software through a wireless gateway bypassing the DCS.

A discovery session should be conducted to identify critical control valves, see if they are digitally integrated with valve diagnostic software and ascertain if the HART communication is still working (not just the 4-20 mA signal). In addition, each department should be contacted to ascertain their challenges in areas beyond control valves and identify opportunities to improve plant operability and maintainability. Some areas of concern could be manual data collection, inability to predict failures, maintenance prioritization, optimizing corrosion control, pinpointing fouling, energy overconsumption and leaks.

17 sum IIOT Fig4From the needs identified in this modernization audit, the sensors required to instrument each piece of equipment can be identified. Some measurements will be displayed in the historian and some in the control system. Simple applications such as data collection do not need specialized software.

Applications can grow domain by domain. Many plants have started with a single sensor per piece of equipment then added more sensors to gain additional insight.

Once the smart valve positioners and additional sensors are in place, personnel will spend less time on manual data collection. They also can predict failures, prioritize maintenance, optimize corrosion control and detect leaks. They can use wireless acoustic transmitters on relief valves to monitor releases and passing. Personnel are usually surprised to detect so many failures when the system is activated, since they were not visible in the past.

This added capability drives maintenance activities and operations, reduces cost, downtime, losses and incidents. Behavior will change from a reactive maintenance culture to a predictive one that identifies problems early and helps to prevent failures.

It is interesting to note that an intelligent valve positioner is actually a collection of sensors conveniently housed in the positioner enclosure mounted on the valve. These sensors monitor position, supply pressure, actuator pressure, temperature and air mass flow (through inferential sensors). In other words, valves are monitored by several sensors just like other equipment such as heat exchangers and pumps. The principle is the same—these sensors collect data analyzed by algorithm in the positioner to diagnose the valve, although some diagnostics and visualization is done by software on a computer.

Along this vein, if electric actuators and motor-operated valves (MOVs) are hardwired or use proprietary digital communication networks, they should be upgraded to use standard FOUNDATION fieldbus communication instead to make the MOV diagnostics accessible. This is so that they can be part of a predictive maintenance program on the premises or part of the IIoT connected service solution. It doesn’t matter if the rest of the plant is using 4-20 mA and on-off signals; the MOVs can still use fieldbus (Figure 3).

Plants built on FOUNDATION fieldbus may have intelligent on-off valves digitally integrated through the fieldbus network. In this case, the on-off valve diagnostics can also be monitored through IIoT-based connected services (Figure 4).

17 sum IIOT Fig5Step 3: Deploy Predictive Analytics Software On-premise

Plants store lots of process data while analyzing only a small amount of that data. Most plants today do not capture much equipment data at all.

Control valve data is collected by the sensors in the valve positioner. This valve data has to be analyzed to provide actionable information to service engineers, however. Some analytics are done in the positioner itself; others are done in valve diagnostic software. Most diagnostics are non- intrusive: They are performed while the valve is controlling without disrupting the process. Other diagnostics are intrusive and can only be done when the process is not running.

Certain valve diagnostics are continuous and others are scheduled on a periodic basis. Fieldbus positioners, for example, continuously conduct performance diagnostics, so this diagnosis need not be scheduled. Intelligent on-off valves and MOVs that are integrated using standard fieldbus protocols can be managed from the same IDM software as the control valves and other instrumentation.

A simple dashboard based on the electronic device description language with an at-a-glance view of the overall health of the valve package will be the first place instrumentation readings appear (Figure 5). From there, instrument technicians can zoom into greater levels of detail such as valve diagnostics, including description of problems along with recommended action (Figure 6).

17 sum IIOT Fig6Some process equipment challenges require more advanced solutions with more than one measurement needed to diagnose the health, determine the performance and detect overconsumption of the equipment. For instance, vibration alone is not enough to get a complete picture of pump, compressor or fan health.

By deploying smart positioners, intelligent on-off valves, digitally integrated MOV and software, valves become smart valves. Similarly, by deploying sensors and software, process equipment becomes smart, connected equipment; pumps become smart pumps.

This software extracts actionable predictive information from raw sensor data. For instance, each heat exchanger bundle is trended to visualize how fouling responds to product blends and anti-fouling chemicals. Valve and equipment diagnostic software can run on an on-premises server—there is no need to connect to the cloud in this case, so an internet connection is not needed.

Because of all these factors, consideration must be given to a budget for engineering and commissioning.

As stated earlier, the solution must be backwards compatible with the existing control system as well as historian software in the plant. OPC applications form the software layer for IIoT. An additional layer of middleware software should not be required; it also shouldn’t be necessary to replace the existing historian platform.

With special software, the plant also can gain the ability to pinpoint fouling and energy overconsumption, and optimize fan speed. This ensures high availability of this equipment at low cost, reduced maintenance time, reduced energy consumption and more.

Step 4: Review Work Processes

Once the smart positioners, sensors and software are in place, the standard operating procedures (SOPs) can be modified to proactively use the software in the daily operation and maintenance of the plant, rather than having to manually inspect valves and equipment. Rewriting SOPs is an important step that should not be missed.

If the plant is managing valves on premise, the SOP for engineers should be to review the instrument diagnostic alarm log each day to catch valves with developing issues and to drive maintenance based on that. The SOP for a complaint from operations about a valve would be to check the software first, before going to the field to verify a problem with the valve and what’s needed to fix it.

Similarly, if the plant is managing process equipment such as pumps and heat exchangers on premise, the SOP for engineers is to also review the alarm log every day to spot equipment that is developing issues early and drive maintenance accordingly. To put this into place, maintenance should get predictive alarms before operations and before trip.

Lastly, staff must be trained to use the new information. Once software is set up properly, the plant will get into a “check the software first” mentality, which saves time and reaps the benefits.

Step 5: Enable IntRAnet of Things

A site may not have sufficient staff with valve diagnostics, vibration analysis or corrosion experience. This can be a particularly difficult problem in areas challenged with attracting employees for work in remote sites away from their families.

By connecting the valve and equipment condition monitoring systems to an enterprise intranet, the data from the site can be accessed across the internet by company employees anywhere in the world, such as an onshore office or a global center of excellence with valve, vibration analysis and corrosion experts. Access is not granted to external vendors and service providers. This is more of an IntRAnet of Things than an IntERnet of Things.

Intranet connectivity enables some personnel to work in an office near their homes rather than on an offshore platform or other remote area. It also lowers the capital and operational cost since offshore installations can have smaller living quarters, and less transport logistics are required.

Step 6: IntERnet of Things Business Models

A plant may have fieldbus valve positioners and wireless sensors but without an internet connection for remote monitoring; this is not yet IIoT.

The valve or process equipment manufacturer’s expert knows the equipment best but is not onsite. A site may not have sufficient personnel to troubleshoot problems. In the past, a remote expert would have to request site personnel to run various tests, take photos and make screen captures, then send them across communications channels. Problems could take days to resolve under this scenario.

By connecting the systems to the internet, access to data from the site can be granted to selected external vendors and service providers anywhere in the world. This is the full Internet of Things architecture. Digital valve positioners and sensors with IIoT enable a digital transformation of outsourced business models.

BUSINESS MODELS

Some independent service providers and OEMs can remotely monitor the health of equipment in plants. Their experts, who are in a central location, watch the status of equipment for which they’ve been granted access. These can be subscription-based services where the plant pays a monthly fee per asset (such as a valve or compressor). The service provider alerts the plant to equipment issues that are developing and generates reports for equipment health and performance, which drives maintenance in the plant.

The instrumentation involved in this service can belong to the plant, but the service provider could also provide the instrumentation and use its own software. In that second model, no upfront capital investment for the plant is required. Instrumentation and software is included in the subscription fee, which is an operational expense. For instance, in the case of pump monitoring, the service provider would install vibration, pressure and temperature transmitters on the pump, motor, mechanical seal and strainer, etc., to collect required data.

Furthermore, the manufacturer’s factory-trained personnel or a maintenance service provider might carry out the maintenance tasks to ensure availability and efficiency of the equipment—an outcome-based model that might possibly mean bonus payments when an agreed level of service is attained. For instance, in the case of a valve, the manufacturer would not only provide a report listing problems, but also go to the site to fix those problems.

Using the data from the equipment, the service provider could predict developing issues before failure or trip, avoiding downtime and helping to troubleshoot equipment while getting production back to capacity sooner. If the plant has a problem with a valve, they can call the valve manufacturer’s pool of experts, which can remotely access and diagnose the valve. In this scenario, problems could be solved in minutes instead of days of bouncing emails back and forth.

CYBER SECURITY AND IT/OT INTEGRATION

Considering the multitude of asset classes in a plant such as valves, compressors and pumps, and more, several manufacturers might have to be granted access to equipment data. This requires developing security with specific access rights for each vendor. Such arrangements already exist in many places. Since IIoT involves both the internet and instrumentation, the IT and the I&C departments (information technology and operational technology) must work together. Like the saying goes: “good fences make good neighbors.” A clear boundary of responsibility between IT and I&C should be developed, usually a demilitarized zone with firewalls at level 3.5 of the enterprise architecture.

In some plants, the equipment monitoring system is separate from the control system. The wireless sensors send their data through the wireless gateway and a 3G mobile router straight to the software in the cloud, bypassing the DCS. This architecture is used for outsourced, remote monitoring services. Since there is no connection to the control system or plant networks, the plant IT department need not provide a network connection.

IMPLEMENTING IIOT

Many suggest that developing a plan for IIoT for the plant should be a three-year process starting with a discovery session to uncover modernization opportunities around the plant. The later steps of the IIoT strategy need not have much detail initially.

With IIoT in place, the plant can be run and maintained in a proactive and less reactive manner. Personnel will spend less time collecting data, and have more time to work on the equipment, which improves reliability and performance.


JONAS BERGE is director of applied technology, Emerson Automation Solutions (www.emerson.com), Singapore. Reach him at This email address is being protected from spambots. You need JavaScript enabled to view it..


GLOSSARY

HART: Digital communication protocol superimposed on top of 4-20 mA analog signals. Used between handheld field communicator and instrumentations such as transmitters and valve positioners, and in some plants also for IDM software.

Fieldbus: Purely digital networking used between instrumentations such as transmitters and valve positioners, and the control system including IDM software. Designed specifically for the industrial plant environment; long distance, hazardous areas, time-critical, etc.

Distributed Control System (DCS): The system that controls the process, by reading sensors and manipulating valves and other final control elements. Consists of input/output system connecting to field instrumentation, controllers executing the control strategy, servers for data storage and process supervisory function, as well as workstations for operators and system configuration.

Intelligent Device Management (IDM) Software: The software part of an asset management system enabling central device configuration and condition monitoring as well as calibration management.

 

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