Wireless Gas Monitoring : Gas detection system architecture

Gas detection is a power-hungry operation, so the main system must be wired to a power source. The cost of such systems, including the cost of planning, design and running conduits for power and signal wires, trenching, and other installation details, can be in the neighborhood of $10,000 per device. Gas detection systems covering all critical plant points have traditionally been specified at the front end engineering and design (FEED) of the plant design, but coverage for all possible points is typically not financially feasible. Furthermore, most of the legacy gas detection systems in use today were specified prior to plant expansions and increased safety awareness. However, as significant incidents and new standards drive heightened interest in plant safety, and as plant systems age and experienced workers leave the workforce, there is a need for tighter monitoring of gas leaks. Filling this need with wired sensors is prohibitive, not only because of the wiring expense, but for many sites, because there is minimal workable space to add wiring or other necessary infrastructure.

Personal or wearable gas detectors can provide a layer of protection, but the accuracy of these devices is poor with 20-25% accuracy as reported by experts in a recent National Fire Protection Association (NFPA) conference. NFPA speakers highly recommend augmenting of personal devices with more reliable fixed gas detectors in potentially dangerous areas. Installing fixed detectors, would better warn workers against entering dangerous areas, protecting them from harm. Regardless of whether a company is deploying fixed or personal detectors, the detectors should be networked so workers in the vicinity are aware of the hazardous condition.

In our next post, we will explore the wireless connection function and how this technology removes the physical and economic barriers associated with wired gas detection devices.

by: Wil Chin, Vice President of Marketing and Business Development at United Electric Controls

Joe Mancini, Senior Product Manager at United Electric Controls

Greg LaFramboise, Retired Wireless Technology Lead, Chevron


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Wireless Gas Monitoring : The emerging solution for improving plant safety.

Industrial processes such as oil and gas production facilities, refining, chemical production and power generation often involve toxic and combustible gases, which can create serious hazards if they escape into the air. Toxic hydrogen sulfide (H2S) and combustible methane (CH4) are among the most widely produced and most dangerous industrial gases.

To minimize risk to personnel and plant safety, plants often deploy early warning devices such as gas detection systems, which require expensive infrastructure and seldom cover all of the potential leak points. This concern is driving a trend toward augmenting existing wired gas detection coverage with wireless sensors, which can significantly increase monitoring coverage with minimal new financial outlay.

In this blog series on wireless gas monitoring, we explore this emerging solution for improving plant safety and kick off by taking a look at some gas sensor basics. In the subsequent posts, we will describe gas detection system architecture, applications of wireless gas monitoring and explore some operating issues that wireless gas monitoring may raise.

Gas sensor basics

A typical gas detector identifies and monitors gas leaks, outputting an electronic signal such as a 4-20 mA, HART, or Modbus wired signal, to a dedicated fire & gas (F&G) system, controller, PLC or control room which sets alarms or guides corrective action. For toxic gases, those signals represent the presence of gas in parts per million (PPMs). For combustible gases they represent the percent of the the lower explosive limits (LELs).

A number of technologies are used to detect the presence of gases. Infrared (IR) technology, which is among the most commonly deployed, monitors gas concentration based on the principle of infrared absorption. Gases like methane absorb specific infrared wavelengths. The electronics module computes the gas concentration based on the amount of absorption.

Electrochemical sensing, another commonly applied technology, measures the concentration of a target gas by reacting with the gas and producing an electrical signal proportional to the gas concentration. A typical electrochemical sensor consists of a sensing electrode and a reference electrode separated by a layer of electrolyte.

Sensing technologies vary in reliability, depending on the properties they are measuring and on the types of gases involved. Electrochemical detectors, for example, tend to be more reliable for specific gases, like hydrogen sulfide, but may lose effectiveness after continuous exposure. Infrared technologies on the other hand tend to be more reliable for detecting LELs and may perform well for up to five years or more. In addition to the sensors deployed in gas detectors, a detection system typically includes a controller or a plantwide fire & gas control system with HMIs, alarm systems, and relays connecting to valves, pumps, or whatever final element might be needed to suppress a gas leak and/or HVAC and fire suppression systems to suppress a fire.

In our next post, we will zoom a level out and examine how a gas sensor is fitted to a typical detector and how that detector plays a part in a gas detection system architecture.


by: Wil Chin, Vice President of Marketing and Business Development at United Electric Controls

Joe Mancini, Senior Product Manager at United Electric Controls

Greg LaFramboise, Retired Wireless Technology Lead, Chevron

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Mechanical Switch Upgrades Made Easy

When considering upgrading the electro-mechanical switches that have been in service for many years, the task can seem daunting. These 2-wire alarm and shutdown devices have served the plant well for many years. Many of the switches have been in service for more than 15 years without failure. But these switches are blind (lack self diagnostics) and are difficult to calibrate.

Process transmitters seem like the obvious choice to replace these switches. Transmitters include diagnostics and don’t require calibration inspections as often as their mechanical brethren. But replacing a mechanical switch with a transmitter is overkill. The unit cost of a mechanical switch versus a process transmitter has a differential of 1.5 – 2 times the original cost of the switch. On top of that, there is wiring, analog inputs and control schemes to consider. And because the plant was built in the 1970s, there are switches everywhere!

Where does the One Series 2-Wire get its power? Directly from the digital input (DI) of the control system. By using a small amount of leakage current taken from the DI, the One Series can provide the same alarm and shutdown functionality previously provided by the mechanical switch – using the same 2 wires and unmodified control scheme.

2slpm041 (safety transmitter)

By using extremely efficient (e.g., low) power management techniques, the One Series is able to scavenge just enough current from a typical DI without tripping it and provide the same on/off switch signal formerly provided by replaced electro-mechanical switch. This patented technology allows the One Series to replace any mechanical switch that is connected to a PLC or DCS control system input and utilize the same switch control scheme and wiring.

No wiring or programming expenses. No MoC considerations – replace a switch with another switch. The cost of the upgrade is the cost of the One Series.


Is there an alternative? One that provides easy adjustability, self diagnostics and can operate using the existing plant wiring and control scheme? Yes! Consider replacing your electro-mechanical switches with a new breed of switch – the One Series 2-Wire electronic switch. The One Series provides IAWTM self diagnostics, configurable set point and deadband, digital process display and operates on the same 2 wires and control scheme as the old mechanical switch being replaced.


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Ethics and Decisions

Ethics green highlighter

In life, we are all faced with difficult decisions. Whether they are personal or professional decisions has no bearing on the level of complexity the human mind sorts through to come to a decision. And when we factor ethics into the equation, determining what the “right” thing to do can be a daunting task.

Fortunately, there are simple questions we can ask ourselves when trying to reach the right decision. In the business world, all of us need to read, understand and consider the ethics policy of the company that we work for. When faced with a business decision, the ramifications can be huge and affect a lot of people, including coworkers and the company’s customers. Here’s a simple test that we can perform to see if our proposed decision is ethically correct. Share the decision with our company’s president! If we are willing to do this, then we can rest assured that the decision is the right decision and follows the corporate ethics policy.


In our personal lives, we have to compare a decision we are about to make with our own personal code of ethics. What are we comfortable with? How will our decision affect other members of our family? Are the consequences of our decision worth sticking with it? Well, as you may have guessed, there’s a similar ethics test for this one, too. Share the decision with our mothers! If Mom agrees with our decision, we know intuitively that our decision is the right one.

There’s one more test we can perform to test whether a decision is ethical. This one is a blend between our personal code of ethics and the corporate ethics policy. We must ask ourselves, are we willing to talk about this decision during our next job interview? If the answer is yes, we are about to make the right decision.

If we are willing to take part in all three of these ethics tests before making tough decisions, we will have a high level of confidence that our decisions are ethical and the right thing to do.

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At one point or another, you may have come across the buzzphrase – Big Data. What is it, why does it matter and how can instrumentation users position themselves to ride this trending phenomenon?

Big data is a term used to describe the tremendous volume of structured and unstructured data that a business receives. The ‘Big Data Universe’ is growing exponentially. We are producing and consuming data at an unprecedented rate. Computer Sciences Corporation predicts that data production will be 44 times greater in 2020 than it was in 2009 with individuals creating 70% of all data and enterprises storing and managing 80% of it.

It is worthwhile to note that big data is more than just volume (e.g. petabytes or exabytes). In addition to volume, SAS Institute lists 4 other aspects (velocity, variety, variability and complexity) associated with big data. Here is a simple example of how big data is contextualized in an industrial plant.

  • Volume – Big data in a process plant originates at the sensor level. There is tremendous amount of process information being captured across the plant’s labyrinth of sensors.
  • Velocity – Data that is fed into the control system (e.g. SCADA) should stream in at near-real time speeds and dealt with in a timely manner. Any latency in transmissions could pose a danger.
  • Variety – Data can come in from various sources and formats such as electronic data recorders, PLCs, HMIs and data historians (Dan Hebert, Four ways to Collect Process Plant Data).
  • Variability – Data flow can be inconsistent with periodic peaks (e.g. Peaking power plants where there could be daily, seasonal or event-triggered peak data loads).
  • Complexity – With a complex myriad of different types of information generated in a plant, it is necessary to connect the data dots and establish information hierarchies for effective plant monitoring and control


Data is only as useful as what you do with it and what you can make sense of it. In the words of Thomas Davenport an analytics thought-leader, “The sweeping changes in big data technologies and management approaches need to be accompanied by similarly dramatic shifts in how data supports decisions and product/service innovation”. Big data when processed, analyzed and interpreted correctly is significant because past business performance can be evaluated and future performance can be quantitatively predicted. This arms decision makers with descriptive, diagnostic, predictive and prescriptive information to shape the best corporate strategy.

Moving forward

As an instrumentation user, here are some ways (adapted from Littlefield, M (2015, November/December).Big data analytics. InTech, 12-15)  to prepare yourself as your organization jumps on the Big Data bandwagon.

  1. Stay open and up to date with technological changes. According to InTech’s magazine cover story on big data analytics, “as legacy and next generation application build on top of IIoT platforms, new applications will be held to a higher standard than ever before in the industrial space” (Littlefield, M (2015, November/December).Big data analytics. InTech, 12-15) . Big data vendors need to create not only navigation friendly applications (think consumer apps like Uber) but also ones that weave social, collaborative, search tools and intuitive analytics into its architecture. Imagine, monitoring the state of your power plant’s instrumentation on a mobile platform interface. To some, that concept might be revolutionary while to others, it might be a precarious thought to have something so important hinged on an interface that appears to be skeletal. This will require a paradigm shift.


  1. Always refer back to the corporate strategy to maximise the value of big data analytics. Are you measuring the right process variables at the right places at the right frequency? Can the measurement data you are currently collecting be repurposed to indicate another aspect of operational or maintenance status? Can you expand the capability of your instrumentation to obtain additional measurement points? Also, as more companies adopt big data analytics, you can expect more cross functional collaboration between various departments (e.g. EHS, quality, asset performance management) in your organization to bring more structure to corporate goals (Littlefield, M (2015, November/December).Big data analytics. InTech, 12-15). If you are in a position to influence, be the voice that keeps everyone on track and gather only information that matters.


  1. Skills upgrade. Companies that embark on big data programs will invest in training their employees with the hope of ‘home-growing’ data science teams. In the long run, this is more cost effective from an organizational standpoint instead of outsourcing data services. Actively participate in these trainings, volunteer if need be, or even consider investing in a big data analytics course that is relevant to your area of expertise. Knowledge is power.
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Instrumentation Symposium

For the fourth consecutive year, UE has attended and exhibited at the Instrumentation Symposium held at the Mary Kay O’Connor Student Center on the campus of Texas A&M University (TAMU) in College Station, TX. This year marked the 71st symposium. It’s hard to believe that this symposium, featuring the latest products available for industrial plant process, safety and monitoring, has been running since the mid-40’s!

Scott, Ken and Chan at TAMU

The symposium provides a unique opportunity for vendors (like UE), to come in contact with the committee members that write the standards for process safety. This year, proposed changes to the IEC 61511 standard were highlighted by Dr. Angela Summers, a committee member and president of SIS-TECH. In attendance were process safety product vendors (like UE) and plant managers who are responsible for implementing the safety instrumented functions outlined in the standard.

Chan Scott and Rick at the symposium

Chan, Scott and Rick

With process safety playing such a huge role, this year the symposium organizers decided to create two separate presentation tracks – one for process safety and the other for process control and monitoring. UE products shown at our exhibition booth, including the 120 Series, One Series hybrid transmitter-switch and the One Series Safety Transmitter, are applied in each of these functions.

Texas symposium Mary Kay O'connor

Rick Frauton, Sr. Product Marketing Manager for UE, made contact with Doug White, Senior Lecturer and Departmental Safety Officer at TAMU regarding their need for the latest process safety products to support their engineering curricula. In 2016, UE will be donating various products from their portfolio, including the One Series Safety Transmitter, for use by these young engineering students. Mr. White is in the planning process for rebuilding their distillation column so UE’s gift to TAMU is timely and greatly appreciated.

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Ageing plant infrastructure: What does it mean for instrumentation users?

In 2013, The Economist published a report about the impact of ageing infrastructure in the process manufacturing industry. The study explored how ageing infrastructure has affected process manufacturing operations globally and identified broad strategies that corporations are implementing to overcome the problems associated with this inevitable phenomenon. More than 360 senior corporate executives from the chemicals, oil and gas, utilities and natural resource industries were surveyed in this study, providing high level insights on what corporations plan to do with their ageing plant systems. Regardless of the plan, there will be an impact on a plant’s state of instrumentation. What is trending in such corporate plans and how should instrumentation users position themselves to embrace the change?

ageing-Large (1)

General trends

  1. A significant majority of executives (87%) report that ageing plant infrastructure has affected their operations in some way or another and at least a third of these high level executives indicate that their companies have plans to increase spending on infrastructure.
  2. One of the top priorities for corporations would be to invest in new technologies that can help plants increase their efficiency while decreasing the risk of infrastructure failures. The reputational harm that comes from a plant failure can take a long time to repair and companies cannot afford that.
  3. Corporations are now viewing infrastructure maintenance and upgrading as more of a growth enabler rather than a stopgap measure.

What does it mean for instrumentation users?

In essence, change is happening and will occur in greater intensity. Adoption of new technologies is key to winning the business race. Instrumentation managers who are in tuned with the corporate philosophy towards an infrastructure upgrade, stay abreast of industry standards and technologies as well as understand the corporation’s risk priorities will navigate the change smoothly. I propose the following considerations:

  1. Understand your company’s philosophy towards an infrastructure upgrade and align your priorities

Does your organization view an infrastructure upgrade as a stopgap measure or a growth enabler? Forward looking organizations view new technologies as an efficiency enabler. Such companies are constantly on the lookout for innovations with the ability to perform predictive modeling that will help the operations team to get ahead of problems, mitigate risks and provide as much information about the state of the plant. These corporations know that a problem detected beforehand costs significantly less to fix than if they wait for it to fail and will do whatever it takes to stay ahead of the game. If that describes your company, the next step is to start aligning your priorities with corporate’s philosophy.

2. Evaluate if there are potential obstacles hindering the upgrade projects.

Map out the roadblocks ahead. For example, the C-suite’s view of risk is associated with legislative and regulatory requirements, so any changes that will jeopardize compliance takes priority, Keeping that in mind, instrumentation managers should perform a thorough landscape study of existing and upcoming regulatory standards to prepare themselves when asked for recommendations for new instrumentation technologies that comply. You need to know what lies ahead to navigate the upgrade project successfully.

3.  Understand which risks your company is most concerned about.

Know what keeps your bosses awake at night. In the survey, risk to operational failure and safety are cited as top decision making factors by executives who consider an infrastructure upgrade. By understanding what concerns your executives and proposing the right solutions, you will be doing more than just embracing the change.

Technology is your ally. Befriend it. To stay competitive, more companies will be willing to adopt new technologies, invest a significant amount of resources (time and money) in a mix of new technologies and enforce sound project planning. Instrumentation managers and users can navigate the changes smoothly by noting the considerations above.


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