Archive | Predictive Maintenance

66

9:30 am
June 30, 2016
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Vibration Monitoring Keeps Aviation Fuel Flowing

Wireless solution increases reliability, safety, and efficiency within a critical transportation operation.

Busy airports require a dependable fuel supply. In this situation, wireless vibration monitoring makes it possible for a fuel-supply company to achieve reliability goals and keep planes in the air.

Busy airports require a dependable fuel supply. In this situation, wireless vibration monitoring makes it possible for a fuel-supply company to achieve reliability goals and keep planes in the air.

At busy airports around the world, the ability to provide a constant, reliable supply of aviation fuel is key. For one major international airport, this responsibility falls to a single fuel-services provider. It stores all aviation fuel transferred to the airport and is the facility’s only fuel-receiving terminal.

Because fuel services are so crucial, the organization’s primary goal is to ensure that the operation stays up and running 24/7/365. At the same time, the plant needs to operate as an efficient business, meaning it is essential to run with minimum manpower.

A case in point

In 2015, the fuel-services company decided to expand and improve its automation system. This move would increase safety, reduce downtime, and free-up time for operators and engineers to focus on other mission-critical tasks. The organization found a solution in Emerson’s AMS asset-management software, coupled with the manufacturer’s CSI 9420 wireless vibration transmitter, both produced by Emerson Process Management, Austin, TX (emersonprocess.com).

The facility manages four fuel-transfer pumps—two of which are running at any given time. Their location and function makes these units notoriously difficult to monitor. Also, due to the heavy workload and ambient temperatures that can exceed 100 F, the pump bearings frequently fail.

Ensuring a steady fuel supply is a primary objective for the world’s busy airports. Automation is helping one aviation-fuel services provider do just that while creating a safe, efficient maintenance environment within its operations.

Ensuring a steady fuel supply is a primary objective for the world’s busy airports. Automation is helping one aviation-fuel services provider do just that while creating a safe, efficient maintenance environment within its operations.

Operators needed a solution that collected more information without increasing the cost or man hours. The solution was wireless vibration monitors, which, in turn, have helped create a safe, efficient maintenance environment.

Background

Although the fuel-service pumps had been monitored for many years, the costs and complexity of running cabling made continuous monitoring out of the question. Before implementing wireless vibration monitors, the plant had to monitor the pumping system through motor and bearing temperature profiles and the intermittent use of handheld vibration monitors. This process presented several problems.

Operators were only able to record intermittent vibration values for the pumps, making it difficult to see true trending. The effort required significant time and did not provide constant monitoring. In the case of an intermittent impact or similar event, it was possible for operators to miss important data.

Wireless monitors offer plants the reliability of continuous monitoring without the added expense of miles of cabling.

Wireless monitors offer plants the reliability of continuous monitoring without the added expense of miles of cabling.

Collected vibration data were entered into a complicated spreadsheet. The problem with such an approach is that even the most robust spreadsheet has significant limitations in its ability to track trends and processes—and provides no predictive-maintenance data whatsoever. Furthermore, while detecting mechanical problems was relatively easy, it was much harder to detect problems that came from process mistakes. That’s because the spreadsheet couldn’t provide an accurate timeline for comparison.

Although personnel could react to events they saw happening, there was little data to show what exactly was going on—which, ultimately, led to the need for more operator and engineer hours to evaluate detected problems and determine a solution. The commitment to operating with a limited staff made it essential that the company reclaim these man hours as quickly as possible.

Problems solved

Implementing wireless vibration monitors, along with a predictive-maintenance software application, dramatically changed this fuel-service provider’s processes. Having pump vibration constantly monitored means that the organization can feel confident personnel will quickly be made aware of any change in function.

In short, operators know that a bearing is heading for failure long before the problem results in process upset. This type of predictive-maintenance capability is vital, as servicing a pump means taking it offline for approximately two months to have it repaired by the manufacturer.

Because the fuel-service facility can’t afford any downtime, the ability to predict pump problems provides peace of mind by allowing personnel to schedule maintenance, not act out of desperation.

Wireless pump monitoring has also increased operator safety. With remote capture of vibration readings, plant personnel have less contact with running machinery than they did when manually recording vibration values. Less contact with the running machines translates to fewer opportunities for accidents that might result in injury.

Moving from recording machine-health data on a spreadsheet to the automatic recording of those data in an asset-management application has been one of the most significant improvements in the operation’s processes.

The asset-management software allows the organization to observe trends in equipment health that simply could not be tracked through a spreadsheet. Alarms are now raised with any abnormal situation and operators are equipped with the tools they need to make decisions quickly. MT

Payoff From Understanding What Could Happen

Managing equipment through an asset-management application allows an organization to better understand what is happening and what could happen on the plant floor. In the case of the aviation-fuel-services company, having vibration and temperature data continuously tracked, stored, and analyzed in the asset-management software lets the plant’s operations and maintenance teams build a timeline around events. This ability is particularly important when a change in process is the catalyst for hardware failures.

Because the software can show exactly when a problem arises, the plant can compare the data with maintenance logs to see if a process change occurred at the same time. In turn, management can rest easy regarding deployed process changes, i.e., know that, regardless of how seemingly insignificant, such changes will always pose a low risk to operations.

On the plant floor, engineers see the most benefit from the plant-wide automation-system enhancement, as they can now spend their time on operational matters instead of pouring over spreadsheets, tracking temperature and vibration data for maintenance. The front-end operators are also relieved that they have reduced their equipment checking time.

Wireless vibration monitors provide the fuel-services people with the flexibility to move toward a holistic machinery-health-management plan. Plant management can feel confident that detailed pump health information is always available and no unexpected shutdowns are lurking around the corner. Management also gains peace of mind that safety is improved, as maintenance teams have fewer reasons to be working around dangerous equipment.

For more information, visit Emerson Process Management at emersonprocess.com

35

6:17 pm
June 28, 2016
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Harley-Davidson’s IIoT Retrofit for Predictive Maintenance

160728harleydavidHarley-Davidson has enjoyed a resurgence over the last 20+ years and one of the reasons has been high-quality, motor bike production. A recent Wall Stree Journal article provided an interesting overview on how companies are moving to predictive maintenance — Industrial Internet of Things — but have relatively new equipment in the factory.  In the article, Mike Fisher, gm at Harley-Davidson’s York, PA manufacturing plant said replacing new machinery with smart technology, such as sensors and better connectivity, wasn’t an option due to equipment being only ten years old.

The challenge for Harley-Davidson, once they decided to add predictive monitoring, was choosing the right sensor technology:

“Making sure you have the right ones can be difficult,” says Fisher, because sensors aren’t made with the particulars of each machine in mind. Often plant managers can’t tell which sensor will most accurately collect the date they want from a machine without a series of test runs–a time-consuming process.”

Fisher also mentioned installation wasn’t easy, either, and instructed that integration work be done by experienced engineers — 3rd party services — for proper calibration. Fisher added that the sensors need to “be placed on or integrated into the equipment so they collect the intended data—not vibrations from an adjacent machine or heat from another motor.”

The article goes on to discuss sensor costs and wired versus wireless, a great read by a mainstream media outlet.

Read the full story here >>

 

1601Iot_logo>> Click here to find more applications, white papers and developments surrounding the Industrial Internet of Things. 

 

176

9:09 pm
June 13, 2016
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Leveraging Continuous Improvement

Pattern assemblies for exhaust manifolds are still in their molds.

For an EPS foam manufacturer, redundancy and consistency are crucial to creating a sustainable production process and a winning culture.

By Michelle Segrest, Contributing Editor

It’s made from 98% air, but it can provide support for a multi-level parking garage. It protects highly sensitive electronic equipment; insulates the foundation, walls, and roofs of skyscrapers; supports the infrastructure of railway systems; and can keep food and medications at just the right temperature.

Expanded polystyrene (EPS) is a lightweight, rigid, closed-cell material that withstands load and back-fill forces, minimizes water absorption, and is a sustainable product that can be recycled again and again.

For more than 40 years, ACH Foam Technologies has been a leading manufacturer of EPS for construction, geotechnical, packaging, and industrial applications. From its nine locations in eight cities across the United States, the family-owned-and-operated company has the capacity to produce 80-million pounds of foam annually.

“We like to say EPS foam is engineered air. This is the magic of our product,” said Todd Huempfner, vice president of operations at the ACH Foam Technologies’ Fond du Lac, WI, facilities.

The two locations in Fond du Lac utilize 170,000 sq. ft. of manufacturing space to produce a diverse line of products made primarily from engineered air, water, and steam.


Click here for more videos on ACH Foam Technologies.


Screen Shot 2016-06-13 at 3.48.45 PMA winning culture

In the mid-1960s, Huempfner’s father, Don, a 20-year veteran of the railroad industry, noticed a special kind of resin being shipped on one of the rail cars. He researched the intriguing product and envisioned potential for a better life for his wife and family, which eventually included 10 children. He took the plunge and opened an EPS manufacturing facility in northern Wisconsin. It quickly became the family business.

“My dad (now 88 years old) is inquisitive, from the school of hard knocks, and he is truly entrepreneurial in spirit, with tons of energy and enthusiasm,” Todd Huempfner said. “He had a lot of mouths to feed. He took a chance at 40 years of age and started the business. With 20 years in the railroad he could have been safe and just retired doing what he was doing. But he had a dream. It’s a great American story.”

Three companies (Advanced Foam Plastics, Contour Products, and Heartland EPS) merged in 2005 to form ACH Foam Technologies. Todd Huempfner’s older brother, Mike, is the chief executive officer and operates from Montana. Mike’s nephew, Jacob Huempfner, is the director of shape operations in the Fond du Lac facility.

With the equal partnership formation of the three companies, ACH faced the challenge of merging three different cultures.

“When you go through a merger like this, you must go through a cultural cleansing,” Huempfner said. “You have to marry three different systems. It’s not a revolution. It’s an evolution. At the grass roots level, it’s all about employee engagement and communication. We have done a good job over the years of having a culture of continuous improvement. At a fairly high level, we understand the systems that we have in place. We know how we want to continue to improve throughout the organization.”

For the Huempfners, a driving philosophy has remained at the forefront—an ideology from management guru Peter Drucker: “Culture eats strategy for breakfast.”

“We focus a lot of our energy and effort around front-line employee engagement and empowerment,” Todd Huempfner said. “We understand the cornerstone of the roadmap to our future. Our biggest focus is building and maintaining a winning culture. This starts with continuous improvement, so we have made a significant investment in this.”

These assembled lost-foam foundry patterns are ready for packaging. The stripe in the patterns is the glue applied by assembly machines.

These assembled lost-foam foundry patterns are ready for packaging. The stripe in the patterns is the glue applied by assembly machines.

Driving continuous improvement

In November 2015, ACH created a new position, Director of Continuous Improvement, to enhance its core competency to always strive to make its product and processes better. Brad Zenko, P.E., brought more than 25 years of engineering, operational, and leadership experience to fill the role.

“Continuous improvement is not an activity, and it’s not a technique,” Brad Zenko stated. “It’s a result.”

The effort is never-ending, he said. “If you are in operations, every day is not just about what went wrong. It’s about how to keep that from happening again. The whole idea behind predictive and preventive maintenance is continuous improvement. From a broader perspective, if you look at maintaining a competitive advantage in business, you have to really embrace continuous improvement because someone is always trying to out-smart you, out-service you, out-something you. You have to be nimble.”

This can be a difficult task, he said. “When you finally master something, you want to stop and take a deep breath. You have about 10 minutes for that, and then you have to think about what’s next on the horizon. How do we make it even better? Even if you have had a really big achievement, you can’t rest on your laurels and say you are done. You never quite get there.”

Zenko works with a team of maintenance and operations professionals and fills the pipeline with everything from simple ideas to game changers. “My job is to find ways to make our processes better, faster, cheaper.”

Ideas for improvement are prioritized into three buckets, Zenko said—business, functional, and organizational. The business side is obvious and includes customer, sales, and market opportunities. Ideas for lean tools and return on investment represent the functioning aspect. On the organizational side, the human element takes precedence with regard to improvements in safety, ergonomics, and finding exceptional, experienced labor.

Full-sized expanded polystyrene (EPS) foam blocks are shown in storage. Heat curing accelerates the curing process of the freshly molded blocks and assures that the material is dimensionally stable.

Full-sized expanded polystyrene (EPS) foam blocks are shown in storage. Heat curing accelerates the curing process of the freshly molded blocks and assures that the material is dimensionally stable.

Zenko operates at a corporate level, so critical improvement implementations are shared across all nine ACH facilities.

“Redundancy is key,” he said. “We don’t want to reinvent the wheel. There is a sense of pride at each site, so sometimes we just look at an improvement from a different perspective. To really multiply the efforts you must put systems in place that do not have to be started from ground zero every time. It’s important to create consistency. Take Starbucks, for example. The taste profile of a Starbucks coffee is consistent from location to location. This is achieved through their quality procedures that outline time, temperature, and roast curves. Consistency of quality and culture is crucial. For ACH, building a culture to do better in all areas is a core goal.”

Zenko said he counts on the people who work on the manufacturing floor to provide the critical insight needed for substantial improvement.

“Improvement starts with asking people what will make their job easier,” he said. “Some people look at continuous improvement as projects, like getting a new machine with more automation that just goes faster. That is an improvement, but it’s the people who interact with the equipment every day. It’s the people who make the difference. Operators see millions of pounds of product go through those machines. We try to help create the standard work, keep people safe, and make sure they are part of the process. This is really powerful.”

Some of the current ACH continuous-improvement projects include initiatives to reduce mold change times, create visual workplaces, build standard systems, and develop 3D modeling to create molds. Some ideas are simple, but impactful.

“For example, we were meeting with some of the operators and talking about how difficult it is to wire down the steam traps,” Zenko said. “One guy who worked previously in construction said he had used pre-looped rebar ties with a spinner tool rather than cutting pieces of wire and spinning them like a bread bag. We bought some twist ties and tried it. Then someone else realized it would be better to have longer ties, so we found 8-inch ties rather than 6-inch ties. It was a team effort, and this is how simple ideas can make a big difference.”

According to Zenko, ACH believes in the Franklin Covey philosophy of being effective with people and efficient with processes. “We may come up with 2,000 things that produce incremental results, but the next idea could be a game changer.”

A coordinate-measuring machine (CMM) is used to confirm 3-D dimensions of lost-foam foundry part.

A coordinate-measuring machine (CMM) is used to confirm 3-D dimensions of lost-foam foundry part.

Product diversity

The two ACH Foam Technologies Fond du Lac facilities create three different types of EPS products—block, shape, and lost foam.

Block represents production of large 3-, 4-, and 16-ft. blocks of EPS produced in big molds to be stored as supply for the cutting lines. They are cut to custom sizes according to customer specifications. A big part of the block business is perimeter, under slab, slope-to-drain roofing systems, and other major construction applications. The company is a leader in manufacturing Foam-Control for Geofoam applications, used where there are unstable soil conditions or for lightweight underground fill. Some examples include a commuter rail in Salt Lake City, UT, where thousands of cubic yards of EPS are encapsulated under a concrete rail, creating a stable infrastructure that will not be compromised with shifting soil.

EPS is also a more time-sensitive solution than traditional soil fill, which requires months of waiting for the soil to settle after filling. Unlike soil fill, Foam-Control Geofoam doesn’t have the challenge of heaving from the earth shifting.

This pattern-assembly machine dips the top portion of this lost-foam part in glue and fits it to the bottom portion.

This pattern-assembly machine dips the top portion of this lost-foam part in glue and fits it to the bottom portion.

Chicago’s Millennium Park is one of ACH Foam Technologies’ high-profile projects.

“We have thousands of cubic yards of Geofoam product underneath that park,” Todd Huempfner said. “You notice that the landscape is beautiful, and it flows evenly. The advantage is the contractor can quickly install the product while avoiding the time required to complete earthwork, such as surcharging, pre-loading, or staging. Under the parking deck is lightweight Geofoam fill under the concrete. It has a tremendous strength-to-weight ratio.”

Shape represents specific custom molding and engineering tooling for a three-dimensional part. This could be DuraTherm PLUS+ qualified shippers for pharmaceutical products, DuraTherm temperature-controlled coolers for the food industry, and DuraTherm protective packaging for anything from wine bottles to electronics and appliances.

Lost foam is similar to shape products, but represents more challenging applications such as turbo housings.

Lost-foam mold tooling requires regular light maintenance for seals, fittings, vents, and other small items. This work is completed in-house.

Lost-foam mold tooling requires regular light maintenance for seals, fittings, vents, and other small items. This work is completed in-house.

“We are one of the most diversified EPS manufacturers in the U.S. market,” Huempfner said. We have high-profile customers in the automotive and RV industry. “When you see an RV on the highway, if you were to cut it in half and see the cross-section, it would be completely encapsulated in our EPS.”

The basic difference between lost foam and custom-shaped molded products is the material that’s used and the end-use application.

“The material in lost foam is very highly engineered and specific for a particular application to be utilized in the casting industry,” he said. “The other shaped products are made with a variety of materials for a variety of applications ranging from pharmaceutical shipping containers to protective packaging components for wine bottles or small appliances.”

In the pre-expansion process, steam is introduced to the resin while an agitator mixes the expanding beads. The heat in the steam causes pentane to be released from the beads. This process takes about 200 sec. to complete.

In the pre-expansion process, steam is introduced to the resin while an agitator mixes the expanding beads. The heat in the steam causes pentane to be released from the beads. This process takes about 200 sec. to complete.

Maintenance and manufacturing

The EPS manufacturing process requires a varied collection of equipment and a high level of maintenance.

Expanding and molding equipment are the key machines used in the process, but downstream secondary applications include lamination lines, sanding lines, cutting lines, pattern-assembly machines, and other equipment. Ninety percent of the company’s maintenance functions are performed in house, said Jacob Huempfner, director of shape operations.

“Air, water, and steam are the lifebloods of our business,” Jacob Huempfner said. “Those support systems must be managed properly at the base level to avoid problems downstream. For some things, such as water and chemical systems for boilers, we rely on outside vendors to ensure we are testing correctly. We do the work, but it is a collaboration to test the water every day, and to determine the appropriate water quality for each plant.”

The manufacturing process begins with pre-expansion, according to Jacob Huempfner. Raw material comes in at a bulk density of about 40 lb./ft.3 in bags that weigh approximately 2,200 lb. The tiny bead material (0.8 mm dia.) is put into a hopper and transferred to the pre-expansion equipment where steam and pressure are introduced. This builds an internal cell pressure, which causes it to soften and then expand.

Once the material reaches the desired bulk density range of between 0.7 and 3.1 lb./ft.3, it is put into the fluid bed dryer where it is stabilized for transferring to the silo system. The product is stored and stabilized for molding in the bead-conditioning room, which is temperature controlled at between 95 and 100 F. The heat stabilizes the material and provides consistency, Jacob Huempfner explained. The boiler room next to the bead-conditioning room provides the heat and steam.

The material then goes to the molding presses, then to the cutting line, and finally to the assembly line. Some of these presses are new and use the latest technology, while others are 20 to 25 years old, according to Todd Huempfner, so they must be well maintained.

There are 10 maintenance professionals located at the two Fond du Lac facilities and about 45 throughout all nine U.S. facilities.

“One of our core competencies is preventive maintenance,” Todd Huempfner said. “Understanding our equipment and what makes it work is crucial. We work with our vendors to ensure that our weekly, monthly, and quarterly preventive-maintenance steps are put in place early within our CMMS system.”

The Kansas City operation has a custom-equipment build shop for secondary application equipment for the lamination, printing, and sanding lines. For all operations, preventive maintenance is crucial.

ACH maintenance professionals are responsible for several mold tools.

ACH maintenance professionals are responsible for several mold tools.

“Our preventive maintenance is not by default. It is by design,” Todd Huempfner noted. “In the early days, there was not a lot of thought about what equipment we would purchase to do a certain operation or what systems we would use. Today, we are trying to standardize that. It gives us better reliability because we have that redundancy. It allows us to minimize our spare-parts list because now we have spare parts in one plant that can be used in three different plants.”

The company’s preventive maintenance includes annual mold equipment rebuild and repairs. This is critical since every product produced goes through the mold equipment. Also, some valves and other parts are replaced regularly.

“We are now replacing some of our older equipment,” Todd Huempfner explained. “We look at the useful life of particular molding equipment as being somewhere around 20 years. When it reaches the 20-year mark, we begin to look at replacement of that equipment, sometimes with one or two more pieces of equipment. Sometimes we can replace two with one because of the advances in technology.”

With preventive maintenance and continuous improvement at the core of operations, Huempfner said consistency and redundancy are the ultimate goals.

“We have done a lot of soul searching in the past few years to figure out how to best implement the continuous-improvement culture throughout our organization,” he added. “We have done a very good job with this at a high level and have moved it into the engagement piece at the front lines.” MT

Michelle Segrest has been a professional journalist for 27 years. She specializes in the industrial processing industries and has toured manufacturing facilities in 30 cities in six countries on three continents.

403

7:09 pm
April 11, 2016
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IIoT Maturation Coming?

grant gerkeBy Grant Gerke, Contributing Editor

February’s inaugural “Industrial Internet of Things” (IIoT) column discussed how the massive move to more sensors and analytics in manufacturing isn’t just a passing fad: It’s transformative. How do companies implement a data strategy with current production systems in place?

Each company needs a starting point in the IIoT journey, but a fully realized data strategy is hard to wrap your arms around today—and was even harder in 2012. That’s when Southern Company, Atlanta, an energy producer and transmission line supplier, decided to tackle the problem. The company is a large energy player in the deep-South region, with 27,000 miles of transmission lines that run through Georgia, Florida, Alabama, and Mississippi, in addition to operating several natural-gas and generation assets.

In a recent manufacturing webinar, Elizabeth Bray, principal engineer at Southern Company, discussed some newly enacted pilot projects involving the corporation’s transmission businesses and the move toward condition-based monitoring for its transformers at more than 3,700 substations.

Before the recent pilot, Southern Company began to add sensors and monitoring capabilities to make a future business case for a centralized program. Southern Company uses the eDNA data historian and PRiSM modeling from Schneider Electric for its transformers. These tools allow operations and maintenance teams to organize data into easy-to-read charts on monitoring screens and identify rates of changes or current deviations for its assets.

One example of success in the recent pilot program alerted a maintenance engineer to capacitor issues with a particular transformer. The eDNA trend tool and PRiSM modeling allowed centralized monitoring teams to identify a rate-of-change alert and allow maintenance to be performed before a peak period could cause downtime.

The eDNA trend tool and PRiSM modeling allowed Southern’s centralized monitoring teams to identify a rate-of-change alert and allow maintenance to be performed before a peak period could cause downtime.

The eDNA trend tool and PRiSM modeling allowed Southern’s centralized monitoring teams to identify a rate-of-change alert and allow maintenance to be performed before a peak period could cause downtime.

This is a great example of software and platform analytic delivering on a large sensing development. In Maintenance Technology’s “Final Thought” column, guest columnist Rene G. Gonzalez noted that this type of trend is quite pervasive in the energy industry. As an example, he cited a typical refinery as increasing its number of sensors from 20,000 five years ago, to 100,000 today.   

Some industry observers, such as Joe Barkai, former VP of Research at IDC, Framingham, MA, are pushing for standardization of instrumentation and devices to reduce costs for manufacturers. According to Barkai, “There aren’t enough standards for the industrial IoT space, and the robust use of standards is critical to accelerate innovation and scalable IoT ecosystems.”

While Barkai is right, most enterprises need solutions now to visualize trapped machine and system data for maintenance teams. With the increasing number of mergers and acquisitions added to the mix, large manufacturers are now assimilating disparate platforms and control architectures to the current plant-production systems.

John Rinaldi, president of Real Time Automation, Pewaukee, WI, spells out specific problems for manufacturers using older controllers in a recent article, titled, “Mining Manufacturing Data | Leveraging Trapped Data for Results” (automation.com, Aug. 21 2015). “Many controllers,” he wrote, “do not have the software and hardware to communicate data to asset-management and information systems using current computing methods.”

Beside the exceptional computing power of the cloud, industrial networking is another huge component of IIoT. Rinaldi pointed to the advantages of intelligent network gateways, which can “extract information residing in PLCs and communicate data to maintenance-management or asset-management systems.” This allows disparate networks or systems to communicate and even perform math functions on process data and send email alarms to maintenance technicians on changes-of-states.

Operations and maintenance now can measure machine cycles, runtime, and other data to perform predictive maintenance without disrupting control architectures and plant performance. Also, a minimal capital investment solution holds water with management. MT

Grant Gerke is a business writer and content marketer in the manufacturing, power, and renewable-energy space. He has 15 years of experience covering the industrial and field-automation industries.

80

4:02 pm
April 6, 2016
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White Paper | Predictive Analytics for Power Plants

Power producers are encountering many changes to their business model and remote monitoring — along with predictive analytics — is an attractive value proposition to end users. GE’s Predix platform offers SmartSignal, a software system that models historian plant data and constructs anomaly data to measure current conditions at a power plant. The modeling is called Variable Similarity-Based Modeling (VBM) technology and can be teamed up with GE’s Industrial Performance and Reliability Center (IPRC) to provide a comprehensive reliability solution.

This white paper introduces key concepts from the SmartSignal software and examines three power plant case studies.

Read White Paper >>

Maintenance Technology’s IIoT page | Find out more about edge computing and other proactive maintenance approaches. 

57

5:55 pm
March 18, 2016
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Going With the Grain

Unloading Corn

Advanced monitoring and diagnostics help a large-scale grain manufacturer improve its maintenance processes.

You never know what you might see while driving down a country road: a herd of grazing cattle, a quaint produce stand, or a beautiful beam of sunlight shining through massive towers on a grain farm. Looking at those picturesque storage bins in the haze of a mid-summer afternoon, you might not realize they can contain as much as $4 million worth of product. Imagine the impact on a farm or grain elevator and the safety issues for those working at the facility if something were to happen to the grain.

Delivering harvested grain to storage bins and ensuring that ideal conditions exist inside such units are two major components of a large-scale grain manufacturer’s operation.

Delivering harvested grain to storage bins and ensuring that ideal conditions exist inside such units are two major components of a large-scale grain manufacturer’s operation.

The challenge

Delivering harvested grain to storage bins/silos and ensuring that ideal conditions exist inside such units are two major components of a large-scale grain-manufacturing operation. Once harvested, grain is moved from storage trucks or containers on the ground to the top of the large storage bins. From there, it is either dumped into a bin or transported across a conveyance system that connects multiple bins. These systems, which run across the tops of the storage bins, make it possible to fill multiple units from one conveyance system. Over time, the system’s many moving conveyor parts can fail or slip.

Moving the grain to the storage bin is only half the battle. The other half is ensuring that the product is properly stored.

Once grain has been safely transferred to a storage bin, temperature becomes a potential concern. If the temperature inside these bins is too high, it can cause issues with the grain quality. Factors such as an insect infestation or moisture, which causes fermentation, can contribute to temperature spikes. In addition, and in extreme cases, these high temperatures can also cause hot spots in the grain, which can lead to unexpected combustion inside the bin. 

The solution

Ensuring that all bin systems—inside and outside—are running reliably and efficiently, and maintaining proper operating conditions, is essential to minimizing downtime and preventing losses. That’s why some advanced grain-storage facilities are implementing a combination of remote-monitoring software and sensors to provide in-depth insights into their operations. With this technology, they are able to monitor temperature increases inside grain bins, as well as component wear and overall operations on conveyance systems. Collected data provide a better understanding of how their systems are functioning and what aspects may require maintenance.

This was the case with a grain manufacturer with operations across the central U.S. Due to the size of the enterprise, diagnosing problems in conveyor systems or storage bins would be a time-consuming and costly process. The company chose to implement hazard- and temperature-monitoring solutions from TempuTech (Byhalia, MS), a provider and original-equipment manufacturer (OEM) of grain-management systems, to take its monitoring and diagnostics capabilities to the next level.

One of the biggest problems facing TempuTech’s services organization, however, was the amount of “windshield time” that it could take to complete the diagnostics process, obtain parts, and complete a repair for its customers. When a problem occurs at a customer’s facility, that relaxing, scenic country drive is soon replaced with multiple trips back and forth to figure out what’s wrong and to take the necessary steps to quickly get the operation back to normal.

First is the trip to the facility to determine the source of the issue, then back to get the right parts—or, in some instances, waiting on site for as many as two days for the necessary parts to be delivered—and finally, back to the site to begin the repair or replacement. All the while, grain-facility management is losing money from a shutdown.

To combat these problems, TempuTech selected GE’s Equipment Insight solution, powered by the cloud-based Predix diagnostics platform, to augment its existing offerings. Equipment Insight is an out-of-the-box remote monitoring and diagnostics solution designed to help OEMs and their end customers improve system performance, grow profits, and reduce operating costs. An Industrial Internet solution, it allows OEMs to securely collect and analyze machine data from intelligent devices in the field and to relay key information to their employees and end users. The system offers on-site viewing, virtual monitoring through a secure cloud environment from mobile devices or browsers, and the ability to control grain-transfer operations across a facility.

For TempuTech, Equipment Insight enables improved visibility into asset health and better monitoring capabilities of its solutions; ultimately streamlining its maintenance processes, providing better service and support, and enhancing their relationships with end customers. While its hazard- and temperature-monitoring systems already provided improved capabilities and valuable data for the grain-handling facility, supplementing them with GE’s Equipment Insight solution took the site’s monitoring and diagnostics capabilities to a higher level.

Together, the two companies offer customers a comprehensive solution capable of real-time, proactive alarming; automatic backup and redundancy features; mobile capability; customizable reports; and delivery of in-depth data when alarms are triggered.

With the temperature-monitoring system in place, standardized temperature reports can be sent directly to the manufacturing-facility operator on a daily basis so that grain temperature can be reduced as needed to protect the product from contaminations, infestations, and hot spots.

Moreover, with the hazard-monitoring system, the operator can now pinpoint problems in the conveyor systems, i.e., belt misalignment and slippage, speed variation, and overheated bearings, thus enabling maintenance to be performed as it is needed and before a large-scale shutdown is required.

Through the pairing of TempuTech’s temperature- and hazard-monitoring systems and GE’s Equipment Insight solution, grain-facility managers can analyze a combination of compiled information and turn it into actionable insight. This ability has helped TempuTech improve its services capabilities in that it is now able to identify problems faster and more efficiently while providing increased visibility into the health of a customer’s assets. It can also schedule service and maintenance before downtime occurs—before the grain manufacturer even knows there’s a problem.

With the data collected and analyzed by the solutions, TempuTech can show up onsite with the right parts in hand, the moment that an issue is detected, reducing windshield time for its employees and repair time and costs for its customers.

Diagnosing problems in grain conveyor systems can be a time-consuming and costly process.

Diagnosing problems in grain conveyor systems can be a time-consuming and costly process.

The result

In leveraging GE’s Equipment Insight, TempuTech is transforming its business model from being a break/fix maintenance provider to a proactive partner, helping to eliminate unplanned downtime and increase productivity for its customers. Additionally, its pilot customer, the large-scale grain-handling operation, expects to improve its asset performance, reduce unplanned downtime, and improve decision-making effectiveness.

Based on this pilot implementation, TempuTech plans to offer an integrated system that controls all aspects of a grain-storage facility, i.e., one that combines different applications, devices, sensors, databases, and systems into one mobile-accessible solution capable of starting, monitoring, and stopping key processes, when needed, and creating preventive-maintenance reports.

With its own temperature- and hazard-monitoring systems and GE’s Equipment Insight, the company will be able to provide current and future customers with a solution capable of seamlessly connecting their machines, data, insights, and people.  MT

GE’s Equipment Insight solution is part of the company’s Automation & Controls portfolio, which is part of GE Energy Connections, Atlanta. For more information, visit geautomation.com.

1118

5:20 am
March 18, 2016
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“Pit Crews” Keep Snacks On Track

Cheetos snacks move through an accumulation conveyor at the Perry, GA, Frito-Lay manufacturing facility.

Cheetos snacks move through an accumulation conveyor at the Perry, GA, Frito-Lay manufacturing facility.

High-performance machines require highly skilled professionals who use a race-car team approach to maintenance and reliability at Frito-Lay’s largest North American manufacturing facility.

By Michelle Segrest,  Contributing Editor

Lay's potato chips move up the potato chip incline conveyor to seasoning.

Lay’s potato chips move up the potato chip incline conveyor to seasoning.

The one million-sq.-ft. Frito-Lay manufacturing facility in Perry, GA, operates like a well-oiled, high-speed race-car track.

The operations teams drive the machines, but it’s the 100 maintenance professionals on five specialized teams who work in the garage and in the pits to build, repair, and optimize the equipment—taking it from the shop to the track. They ensure the production stays in constant motion as it circles the refined Frito-Lay course, around-and-around, nonstop, 24/7.

Perry’s director of maintenance and engineering, Craig Hoffman, is the crew chief. The overall maintenance philosophy requires proactive maintenance and methodologies, he said. However, just like a race-team pit crew, they must have the ability to respond to unexpected issues.

“NASCAR teams spend a lot of time in their shops building their cars, analyzing, making adjustments, and fixing problems. We use similar techniques,” Hoffman said. “Our foundation is planning and scheduling, which is supported by preventive and predictive maintenance and root-cause analysis. We do everything we can to make sure our equipment is ready to perform.”

In a facility that produces thousands of pounds of potato chips, tortilla chips, and many other Frito-Lay products per hour, the equipment must stay in optimal condition to deliver high-performance production, he said.

“Our job is to turn the equipment over, in the best possible shape, to the operations group. But every race day there is a situation where you have to respond. When something happens, we go into the pit-crew mentality—it’s all hands on deck. What is constantly on our minds is how to keep our equipment in safe, reliable, food-safe condition so that the drivers can continue to move the lines around the track. We do a great job upfront with our proactive technologies. I would love to say we are perfect. When, however, you have as much equipment as we do, something is going to happen. And we have to be able to respond.” 

The different teams play different roles, yet all share a common goal: to produce millions of pounds of snack foods annually.

The Perry facility houses 15 manufacturing lines that produce all flavor varieties of Frito-Lay snacks, including Doritos, Cheetos, Tostitos, Ruffles, Lay’s, Fritos, SunChips, Stacy’s, Smartfood, Rold Gold, and Funyuns. Built in 1988 with just two lines, the largest of Frito-Lay’s 36 North American manufacturing facilities has built several expansions in nearly three decades, including three production lines in the past 14 months.

Maintenance philosophy

Doritos nacho-cheese-flavored chips travel through the distribution system to packaging. Photos: Michelle Segrest.

Doritos nacho-cheese-flavored chips travel through the distribution system to packaging. Photos: Michelle Segrest.

Hoffman’s team is responsible for the maintenance of countless pieces of equipment, including fryers, ovens, extruders, a fleet of automated vehicles (including cranes and robots), weighers, kettles, pumps, motors, instrumentation, packaging equipment, seasoning-application equipment, boilers, air compressors, air dryers, switch gears, bag-packaging tubes, and several miles of conveyors throughout the facility.

The site’s maintenance professionals are divided into five teams that cover all facets of the facility:

  • core plant – includes all of the machines that manufacture, package, and process the larger, core products such as Lay’s and Doritos
  • bakery area – manufactures, packages, and processes baked products
  • facility – handles buildings, grounds, infrastructure, boilers, compressors, steam system, and other related equipment
  • warehouse – takes care of the shipping and distribution equipment, and all palletizing equipment, robots, and cranes
  • controls – manages the controls infrastructure, all operator interface terminals, PLC programming, and IT systems.

Hoffman teaches planning classes to all Frito-Lay employees. “I always cite the example of changing oil in the car,” he said. “Most people tell you put the car up on blocks, drain the old oil, then put in the new oil. When I change the oil, I go into my shop first and make sure I have the oil filter. I make sure I have the oil. I make sure my jack is in good condition, and I have jack stands for safety. Then I make sure it is time to change the oil. A lot of people tear right into a project without having the right parts or the right information to do the job. To me, this is all about planning.”

“Another example is when you go on vacation,” Hoffman said. “I don’t know anyone who just wakes up one morning and says, ‘I’m out of here.’ You plan the vacation. You decide where you are going to go, what you are going to do, where you will stay. You buy tickets. You put a plan together before you go tackle that vacation, just like we would put a plan together before we would tackle any job. We are making sure we have the right parts, the right information, and the right tools to go execute good work.”

The work comes from the facility’s PM (preventive maintenance) system. Operators provide insight on how their machines are running. Then the maintenance team maps out a plan to restore the equipment to the optimal operating condition. When the plan is set, they schedule and execute it. “If you don’t have a plan, you have no control. If you fail to plan, you plan to fail.”

Even though it is a low percentage of the time, unplanned maintenance also happens, according to Jim Northcutt who is in charge of all maintenance and engineering for Frito-Lay’s 36 North American facilities. He coordinates the facility maintenance managers from the corporate office in Plano, TX, and executes a streamlined maintenance approach across all facilities.

“The company, as a whole, runs very efficiently,” Northcutt explained. “When we do have an unplanned event, the maintenance managers get their team marshaled around making sure they have the right tools and the right expertise to get it corrected and back online. There is not a silver bullet there. It is just really good people who work in our organization who are very talented.”

Best maintenance practices

Maintenance mechanics Mike Day and Dave Maddox oversee shop rebuilds.

Maintenance mechanics Mike Day and Dave Maddox oversee shop rebuilds.

Planning and scheduling is supported with an in-depth PM system, along with highly upgraded technology such as vibration analysis and ultrasound, and carefully crafted PdM (predictive-maintenance) processes.

For corrective work, the planners and schedulers go to the storage area and check out several parts and then kit them for the mechanics, Hoffman said. Then jobs are reviewed with the mechanics. “The key here is to make our mechanics as successful as possible by giving them the right equipment, the right parts, and the right tools to maximize wrench time. This way, when they are out on the floor they have everything they need. It eliminates travel time back and forth and maximizes our ability to perform corrective work and keep our plant in a reliable state.”

When the mechanics receive a schedule, it determines the location of the kitting bin. The bins are numbered and lettered so the mechanic can easily find them and be prepared to successfully perform the job.

The planning and scheduling foundation translates across all North American facilities, Northcutt said. “If you look at it in its most simplistic terms, we plan it, we schedule it, we execute it,” he said. “As a company, throughout all facilities, planning and scheduling is what we hang our hat on.” 

Other best practices include using condition-based approaches and the previously referenced predictive technologies, i.e., thermography, ultrasound, and vibration analysis. Staffing and development is also important, said Richard Cole, director of maintenance and engineering at the Fayetteville, TN, facility.

“It is crucial to have the right people in the right place,” Cole said. “We are continuously developing their skills. We leverage local junior colleges and trade schools to bring in students as interns to work with the mechanics and get training. We have a strong focus around processes and systems, planning and scheduling, work orders, and predictive maintenance. We must always be looking at continuous improvement from scorecards and action plans. Reward and recognition also plays a role in our maintenance strategy.”

Knowing the score

To stay on track, Frito-Lay believes in knowing the score.

“We track our downtime performance here very closely,” Hoffman said. “We have the ability, through technology, to monitor our line performance almost to the minute. I challenge my managers and my mechanics to always know the score. It’s just like how a racecar driver knows what lap he is on, how much fuel he has left, and how much air is in the tires—he knows when to make a pit stop. You always have to know where you stand against the target you set.”

Maintenance planners Tim Waller, Don Reynolds, and Jeff Tuck take a break in the maintenance-parts room. Planning, scheduling, and kitting parts is a key component of the overall maintenance strategy at Frito-Lay.

Maintenance planners Tim Waller, Don Reynolds, and Jeff Tuck take a break in the maintenance-parts room. Planning, scheduling, and kitting parts is a key component of the overall maintenance strategy at Frito-Lay.

Frito-Lay’s key performance indicators (KPIs) include safety scores, such as the number of days the facility has gone injury free. They also measure total downtime, equipment downtime, operation downtime, changeovers, and material-related downtime.

“We have to have our house in order and provide a stable, safe work environment for our operators,” Hoffman said. With multiple changeovers, the quality could go south fast and our operators become extremely frustrated. If we hold our equipment reliability at the highest level, our operators have a very good chance to have a successful day. It allows them to focus on their quality metrics, how their line is running, and how we are holding our product to the highest standard. This is especially important when [it comes to] making food.”

Northcutt said anyone at any of the facilities in the U.S. and Canada can immediately see the metrics.

“I’m an old football coach, and I believe in knowing the score,” Northcutt noted. “Mechanics and those running the equipment from an operations perspective all know the score. This includes everything from planning and scheduling to inventory control to efficiency. Our ability to focus in on performance to improve performance makes us unique as an organization. On a weekly basis, the operations and technical teams come together to talk about outages or failures and then they step back and consider if it’s systemic or a piece of equipment. We call that ‘fix it forever.’”

Frito-Lay promotes internal competitions among facilities to inspire the operations and maintenance teams to keep score on key metrics. The company provides performance reports and ranks the various sites in different categories. There is a national downtime competition throughout the year that measures uptime and unplanned downtime. Winning teams are recognized through various company incentives.

“In this business, we like to know if we won,” Hoffman said. “If you don’t keep the numbers visible to the team, and if they don’t think it’s important to the leadership, their motivation will falter. Keeping the score is the greatest motivational technique we have in this business. Talk to any of my mechanics, they will tell you that I’m all about watching the downtime numbers with a goal of minimal downtime.”

The Fayetteville site’s Richard Cole pointed out that the friendly competitive challenges across facilities are motivational, but the teams also remember they are ultimately on the same side. Successful new processes and systems are shared across sites and the camaraderie that develops is strong. Support is given throughout the company, whether it’s hands-on, directional, or coaching to help personnel at all Frito-Lay sites improve performance.

Keeping up with new technology

Maintenance mechanic Fred Luther uses ultrasound technology as part of routine predictive maintenance.

Maintenance mechanic Fred Luther uses ultrasound technology as part of routine predictive maintenance.

Because Perry is the largest, most complex Frito-Lay facility, it has become the test site for new technology.

“If there is a new piece of equipment, we have very close contact with corporate engineering and our research-and-development team. They want to bring it here and let us try to help make it successful or let us cut our teeth on it and prove it before we deploy it to other facilities,” Hoffman said.

The Perry facility also has technically apt teams. “We are blessed with some of the most highly skilled maintenance and technology professionals in the company,” he added. “So we get all the new toys. It’s kind of cool. It challenges us.”

The teams go through rigorous training with the equipment vendors and supplement it with training at local technical schools. They also solicit other vendors and suppliers to provide training programs and classes on new technology.

Leveraging improvement, energy, and reliability

According to Hoffman, many different facets of continuous improvement are introduced at the Perry site and throughout all Frito-Lay operations. Through root-cause analysis, issues are engineered to avoid repeat failures, and improvement programs are launched to upgrade or harden pieces of equipment to increase reliability.

The team also troubleshoots how to reduce utility consumption while maintaining reliability. They study how to reduce parts costs and the overall cost of making the product.

“Our primary focus in the reliability business is just that…how do we become more reliable?” Hoffman said. “A lot of continuous improvement involves hot teams. So if there is an issue on the floor, for example, repeat failures, or if the operations team cannot get to the quality metrics they need, we will launch a hot team right there. Often cases involve managers, maintenance technicians, and operations professionals. We’ll brainstorm and come up with ideas, call outside vendors, and find some potential improvements.”

Palletizing robots prep product for distribution.

Palletizing robots prep product for distribution.

The focus becomes more than just reliability issues. Hot teams are also formed to solve issues that surround quality, safety, and operation optimization, to reduce the overall cost of the production.

“When you have a major failure or breakdown on a manufacturing line, everything sits there running,” Hoffman said. “You are still using gas to keep the ovens and fryers hot. Electricity is making all the other motors turn, but if you’re not making product, you’re just wasting utilities. If you have a reliable plant, inherently you improve your utility usage because you make product when you are supposed to.”

Frito-Lay supports other programs, including combustion tuning, minimizing fuel usage, and reducing utility consumption.

Production consistency

PepsiCo, Frito-Lay’s parent company, recently celebrated its 50th anniversary. The corporate arm keeps a keen eye on maintaining consistency throughout its processes, Northcutt said.

“Anytime you have a multi-plant environment, you have to have consistency,” Northcutt said. “A Lay’s potato chip made in California or Canada has to taste the same as the ones produced in Georgia. One thing we did well many years ago was rolling out and making sure everyone had the same tools, the same CMMS, the same inventory control, and the same purchasing process. We rolled out ultrasound as our primary condition-based tool. Consistency from one site to the other is something that becomes really important. We make sure to have consistent applications and then everyone is on the same playbook.” MT

Michelle Segrest has been a professional journalist for 27 years. She has covered the industrial processing industries for nine years and toured manufacturing facilities in 28 cities in six countries on three continents.

Frito-Lay Fayetteville Facility Earns Maintenance Excellence Award

The Foundation for Industrial Maintenance Excellence (FIME) organization is dedicated to the recognition of maintenance and reliability as a profession. FIME sponsors the North American Maintenance Excellence (NAME) Award, which is an annual program that recognizes North American organizations that excel in performing the maintenance process to enable operational excellence.

Frito-Lay’s Fayetteville, TN, site was the recipient of the prestigious award in 2011.

Jim Northcutt and Richard Cole were heavily involved in fulfilling the stringent requirements to achieve this honor.

“Jim and I are constantly looking outside of Frito-Lay to study industry trends and best maintenance and manufacturing practices,” Cole said. “It’s important to have opportunities to see what other companies are doing and research new technologies to bring back to the organization.”

Through the NAME Award process and also finding industry partners, including the Univ. of Tennessee Reliability and Maintenance Center and organizations such as SMRP, Frito-Lay has been able to connect with various colleagues to benchmark performance.

“We like to challenge ourselves to find out how good we can possibly be,” Cole said. “This benefits our own culture, as well as the entire American manufacturing culture.”

During the lengthy application and selection process for the NAME award, Cole worked closely with Northcutt at the corporate level to see how the Fayetteville site stacked up as a world-class manufacturing facility.

FIME sends four to five technical experts to assess the site in many different categories for a week. “They then give assessment and let you know how you perform and where you need to improve” Cole said. “Our processes, systems, teams, skills, and leadership hit this high level, so we were recognized for the award.”

Frito-Lay was then able to use the Fayetteville site as an example for its other facilities.

The objectives of the NAME Award, which was established in 1991 as a nonprofit, are to:

  • Increase the awareness of maintenance as a competitive edge in cost, quality, reliability, service, and equipment performance.
  • Identify industry leaders, along with potential or future leaders, and highlight best practices in maintenance management.
  • Share successful maintenance strategies and the benefits derived from implementation.
  • Understand the need for managing change and stages of development to achieve maintenance and reliability excellence.
  • Enable operational excellence.

Winners of the NAME award are site-specific. Some years there are no winners and some years there are two or three winners. It’s a rigorous process, but those who qualify earn the award.

291

2:01 am
March 18, 2016
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Make Sense of Electrical Signals

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Waveforms translate to crucial information about the health of your electrical/mechanical equipment systems. How do you read them?

Edited by Jane Alexander, Managing Editor

Devices that convert electrical power to mechanical power run the industrial world. Think pumps, compressors, motors, conveyors, and robots. Voltage signals that control these electro-mechanical devices are a critical but unseen force. The question is, how do you capture and  and anlyze that unseen force?

Oscilloscopes (or scopes) test and display voltage signals as waveforms, i.e., visual representations of the variation of voltage over time. The signals are plotted on a graph, which shows how the signal changes. The vertical (Y) access represents the voltage measurement and the horizontal (X) axis represents time.

According to the technical experts at Fluke Corp., Everett, WA, an oscilloscope graph can reveal important information, including:

  • voltage and current signals when equipment is operating as intended
  • signal anomalies
  • calculated frequency of an oscillating signal and any variations in frequency
  • whether a signal includes noise and changes to the noise.

Most of today’s oscilloscopes are digital—which enables more detailed, accurate signal measurements and fast calculations, data-storage capabilities, and automated analysis. Handheld digital oscilloscopes offer several advantages over benchtop models. They are battery operated, use electrically isolated floating inputs, and offer the advantage of embedded features that make oscilloscope usage relatively easy and accessible to a variety of workers.

Oscilloscope functions

Sampling. This is the process of converting a portion of an input signal into a number of discrete electrical values for the purpose of storage, processing, and display. The magnitude of each sampled point is equal to the amplitude of the input signal at the time the signal is sampled.

Fig. 1. Sampling and interpolation: Sampling is depicted by the dots while interpolation is shown as the black line.

Fig. 1. Sampling and interpolation: Sampling is depicted by the dots while interpolation
is shown as the black line.

The input waveform appears as a series of dots on the display (Fig. 1). If the dots are widely spaced and difficult to interpret as a waveform, they can be connected using a process called interpolation, which connects the dots with lines, or vectors.

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Fig. 2. Unknown trace adjusted for 3 to 6 vertical divisions.

 

Fig. 3. Unknown trace adjusted for 3 to 4 periods horizontally.

Fig. 3. Unknown trace adjusted for 3 to 4 periods horizontally.

 

Fig. 4. Trigger point is set to the 50% point but, due to the aberration on the leading edge in the second period, an additional trigger results in an unstable display.

Fig. 4. Trigger point is set to the 50% point but, due to the aberration on the leading edge in the second period, an additional trigger results in an unstable display.

 

Fig. 5. Trigger level adjusted to a unique repetitive position, outside the aberration on the second period.

Fig. 5. Trigger level adjusted to a unique repetitive position, outside the aberration on the second period.

Triggering. Trigger controls allow users to stabilize and display a repetitive waveform.

Edge triggering is the most common form of triggering. In this mode, the trigger level and slope controls provide the basic trigger-point definition. The slope control determines whether the trigger point is on the rising or the falling edge of a signal, and the level control determines where on the edge the trigger point occurs.

When working with complex signals such as a series of pulses, pulse-width triggering may be required. With this technique, the trigger-level setting and the next falling edge of the signal must occur within a specified time span. Once these two conditions are met, the oscilloscope triggers.

Single-shot triggering is a technique by which the oscilloscope displays a trace only when the input signal meets the set trigger conditions. Once the trigger conditions are met, the oscilloscope acquires and updates the display, and then freezes the display to hold the trace.

Fig. 6. If the two waveform components aren’t symmetrical, there may be a problem with the signal.

Fig. 6. If the two waveform components aren’t symmetrical, there may be a problem with the signal.

 

Fig. 7. Use cursors and the gridlines to evaluate the rise and fall times of the leading and trailing edges of a waveform.

Fig. 7. Use cursors and the gridlines to evaluate the rise and fall times of the leading and trailing edges of a waveform.

 

Fig. 8. Use horizontal cursors to identify amplitude fluctuations.

Fig. 8. Use horizontal cursors to identify amplitude fluctuations.

Getting a signal on the screen. The task of capturing and analyzing an unknown waveform on an oscilloscope can be routine, or it can seem like taking a shot in the dark. In many cases, taking a methodical approach to setting up the oscilloscope will capture a stable waveform or help you determine how the scope controls need to be set so that you can capture the waveform.

The traditional method of getting a signal to show properly on an oscilloscope is to manually adjust three key parameters to try to achieve an optimum set-point—often without knowing the correct variables:

  • vertical sensitivity: Adjust the vertical sensitivity so that the vertical amplitude spans approximately three to six divisions.
  • horizontal timing: Adjust the horizontal time per division so that there are three to four periods of the waveform across the width of the display.
  • trigger position: Set the trigger position to the 50% point of the vertical amplitude. Depending on the signal characteristics, this action may or may not result in a stable display.

These three parameters, when adjusted properly, show you a symmetrical “trace,” the line that connects the samples of the signal to create the visual depiction of the waveform. Waveforms can vary indefinitely from the most common sine wave that ideally mirrors between positive and negative on the zero axis point or a unidirectional square wave typical of electronic pulses, or even a shark-tooth form.

The manual setup method often requires tediously adjusting the settings to make the waveform readable in order to analyze it. In contrast, some modern oscilloscopes automate the process of digitizing the analog waveform to see a clear picture of the signal.

Fig. 9. Evaluate waveform DC offsets.

Fig. 9. Evaluate waveform DC offsets.

 

Fig. 10. Evaluate period-to-period time changes.

Fig. 10. Evaluate period-to-period time changes.

 

Fig. 11. A transient is occurring on the rising edge of a pulse.

Fig. 11. A transient is occurring on the rising edge of a pulse.

Understanding and reading waveforms

The majority of electronic waveforms encountered in the workplace are periodic and repetitive—and they conform to a known shape. As you train your eye to understand these waveforms, consider their varying dimensions:

  • Shape. Repetitive waveforms should be symmetrical. That is, if you were to print the traces and cut them in two like-sized pieces, the two sides should be identical. A point of difference could indicate a problem.
  • Rising and falling edges. Particularly with square waves and pulses, the rising or falling edges of the waveform can greatly affect the timing in digital circuits. It may be necessary to decrease the time per division to see the edge with greater resolution.
  • Amplitude. Verify that the level is within the circuit operating specifications. Also check for consistency, from one period to the next. Monitor the waveform for an extended period of time, watching for any changes in amplitude.
  • Amplitude offsets. DC-couple the input and determine where the ground reference marker is. Evaluate any DC offset and observe if this offset remains stable or fluctuates.
  • Periodic wave shape. Oscillators and other circuits will produce waveforms with constant repeating periods. Evaluate each period in time using cursors to spot inconsistencies.
Fig. 12. This figure shows ground reference-point measurement indicating induced random noise.

Fig. 12. This figure shows ground reference-point measurement indicating induced random noise.

 

Fig. 13. Excessive ringing occurring on the top of the square wave.

Fig. 13. Excessive ringing occurring on the top of the square wave.

 

Fig. 14. This pattern shows a momentary change of approximately 1.5 cycles in the amplitude of the sine wave.

Fig. 14. This pattern shows a momentary change of approximately 1.5 cycles in the amplitude of the sine wave.

 

Fig. 15. Performing a frequency measurement on a crystal oscillator that has been trend-plotted over an extended period can highlight the effect of drift caused by temperature changes and aging.

Fig. 15. Performing a frequency measurement on a crystal oscillator that has been trend-plotted over an extended period can highlight the effect of drift caused by temperature changes and aging.

Waveform anomalies

The following items reflect typical anomalies that may appear on a waveform, along with the typical sources of such anomalies.

  • Transients or glitches. When waveforms are derived from active devices such as transistors or switches, transients or other anomalies can result from timing errors, propagation delays, bad contacts, or other phenomena.
  • Noise. Noise can be caused by faulty power-supply circuits, circuit overdrive, crosstalk, or interference from adjacent cables. Or, noise can be induced externally from sources such as DC-DC converters, lighting systems, and high-energy electrical circuits.
  • Ringing. Ringing is seen mostly in digital circuits and in radar and pulse-width-modulation applications. It shows up at the transition from a rising or falling edge to a flat DC level. To check for excessive ringing, adjust the time base to give a clear depiction of the transitioning wave or pulse.
  • Momentary fluctuation. Momentary changes in the measured signal generally result from an external influence such as a sag or surge in the main voltage, activation of a high-powered device that is connected to the same electrical circuit, or a loose connection.
  • Drift. Manifested as minor changes in a signal’s voltage over time, drift can be tedious to diagnose. Often the change is so slow that it is difficult to detect. Temperature changes and aging can affect passive electronic components such as resistors, capacitors, and crystal oscillators. One problematic fault to diagnose is drift in a reference DC voltage supply or oscillator circuit. Often, the only solution is to monitor the measured value (VDC, Hz). MT

This article was edited using information supplied by technical experts at Fluke Corp.,  Everett, WA. For more information on this and other testing and measurement topics and technologies, visit fluke.com.

Diagnosing Problems and Troubleshooting

Technical experts at Fluke Corp., note that while successful troubleshooting is an art and a science, adopting a methodology and relying on the functionality of an advanced oscilloscope can greatly simplify the process.

The time-tested approach known as KGU (known good unit) comparison builds on a simple principle: An electronic system that is working properly exhibits predictable waveforms at critical nodes within its circuitry, and these waveforms can be captured and stored.

A reference library of waveforms of a KGU can be stored on some oscilloscopes or printed out to serve as a hard-copy reference document. If the system or an identical system later exhibits a fault or failure, waveforms can be captured from the faulty system—called the device under test (DUT)—and compared with their counterparts in the KGU. Consequently, the DUT can either be repaired or replaced.

CAUTION: For the correct and safe use of electrical test tools, it is essential for operators to follow safety procedures as outlined by their company and local safety agencies.

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