Inspection, Detection and Documentation – The Trifecta of Work in Process

As the rolling hills of the Bluegrass state turn from frost covered gold of winter to sun splashed green of spring, most Kentuckians are gearing up for “the most exciting two minutes in sports”, otherwise known as The Kentucky Derby. While some fans are interested in the glitz and glamour of the event, the real supporters of the sport, the bettors, are seeking out a big payday. A specific type of wager called a Trifecta, a bet that requires picking the first three finishers in the correct order, traditionally yields thousands, if not tens of thousands, of dollars in reward. This is no easy feat.  It is difficult to pick one horse, let alone three to finish at the top. So while the bettors are seeking out their big payday with a trifecta, the stakeholders in manufacturing organizations around the globe are utilizing the trifecta to ensure their customers are getting quality products. However, the trifecta of work in process is valued in millions of dollars.


Work in process, or “WIP”, is an application within manufacturing where the product is tracked from the beginning of the process to the end. The overall goal of tracking the product from start to finish is, among other things, quality assurance. In turn, ensuring the product is of good quality creates loyal customers, prevents product recalls, and satisfies regulations. In a highly competitive manufacturing environment, not being able to ensure quality can be a death sentence for any organization. This is where the trifecta comes back into play. The three processes listed below, when used effectively together, ensure overall product quality and eliminate costly mistakes in manufacturing.

  1. Inspection – Typically executed withWorkinProcess Trifecta a vision system. Just like it sounds, the product is inspected for any irregularities or deviation from “perfect”.
  2. Detection – This is a result of the inspection. If an error is detected action must then be taken to correct it before it is sent to the next station or in some cases the product goes directly to scrap to prevent the investment of any additional resources.
  3. Documentation – Typically executed with RFID technology. The results of the inspection and detection process are written to the RFID tag. Accessing that data at a later time may be necessary to isolate specific component recalls or to prove regulatory compliance.

Whether playing the ponies or manufacturing the next best widget, the trifecta is a necessity in both industries. Utilizing a time tested system of vision and RFID technology has proven effective for quality assurance in manufacturing, but a reliable system for winning the trifecta in the derby is still a work in process.

To learn more about work in process, visit

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When to Use Hygienic Design vs. Washdown

Both washdown and hygienic design are common terms used in the food and beverage industry, and are increasingly being used in the packaging industry. These terms are used in different scenarios and easily confused with each other. What exactly are the differences between them, and in what applications are each used?

Why are hygienic design and washdown needed?

The consumer, and more specifically, the health of the consumer is the core concern of the food and beverage industry. Contaminated food can pose a danger to life and limb. A product recall damages the image of a company, costs a lot of money and as a worst case scenario can lead to the complete closing of the company. To prevent such scenarios, a producers primary objective is to make sure that the food is safe and risk-free for the consumer.image 1

In food manufacturing and packaging plants, a differentiation is made between the food area (in direct contact with the product), the spray area (product-related) and the non-food area. The requirements of the machine components are different depending on which area they are in.

The Food Area

In the food area the food is unpacked, or partially unpacked, and particularly susceptible to contamination. All components and parts that may come in contact with the food must not adversely affect this, e.g. in terms of taste and tolerability.

The following needs to be considered to avoid contamination:

  • Hygiene in production
  • Use of food contact materials
  • Food-grade equipment in Hygienic Design

These requirements result in the need for components that follow the hygienic design rules. If the component supplier fulfills these rules, the machine manufacturer can use the components and the producer can use the machines without hesitation.

Hygienic Design

Many component suppliers offer different solutions for hygienic design and each supplier interprets the design differently. So what does hygienic design mean? What must be included and which certifications are the right ones?

  • The material used must be FoodContact Material (FCM). This means that the material is non-corrosive, non-absorbent and non-contaminating, disinfectable, pasteurisable and sterilizable.
  • Seals must be present to prevent the ingress of microorganisms.
  • The risk of part loss must be minimized.
  • Smooth surfaces with a radius of < 0.8 μm are permitted.
  • There must be no defects, folds, breaks, cracks, crevices, injection-molded seams, or joints, even with material transitions.
  • There must be no holes or depressions and no corners of 90°.
  • The minimum radius should be 3 mm.

Supporting institutions and related certifications

There are different institutions which confirm and verify the fulfillment of these rules. They also support the companies during the development process.


EHEDG – The European Hygienic Engineering and Design Group offers machine builders and component suppliers the possibility to evaluate and certify their products according to Hygienic Design requirements.

image33A – 3-A Sanitary Standards, Inc. (3-A SSI) is an independent, non-profit corporation in the U.S. for the purpose of improving hygiene design in the food, beverage and pharmaceutical industries. The 3-A guidelines are intended for the design, manufacture and cleaning of the daily food           accessories used in handling, manufacturing and packaging of edible products with high hygiene requirements.

image4FDA – The Food and Drug Administration is a federal agency of the United States Department of Health and Human Services, one of the United States federal executive departments. Among other things, the FDA is responsible for food safety.

What does a hygienic design product look like?

Below is an example of a hygienic design product.


  • Stainless steel housing VA 1.4404
  • Laser marking
  • Protection class IP69K (IEC 60529)
  • Active surface made of PEEK
  • EHEDG conform
  • FDA conform

Since the product contacting area is associated with high costs for the plant manufacturer and the operator, it’s beneficial to keep it as small as possible.

The Spray Area

In the spray area, there are different requirements than in the food area.
Depending on the type of food that is processed, a further distinction is made between dry and wet areas.


Areas in the food and beverage production

Here we are talking about the washdown area. Washdown capable areas are designed for the special environmental conditions and the corresponding cleaning processes.


Components which fulfill washdown requirements usually have the following features:

  • Cleaning agent/corrosion resistant materials (often even food compliant, but this is not a must)
  • High protection class (usually IP 67 and IP 69K)
  • Resistant to cleaning agents

Photoelectric sensor for washdown requirements

Ecolab and Diversey are two well-known companies whose cleaning agents are used for appropriate tests:

Ecolab Inc. and Diversey Inc. are US based manufacturers of cleaning agents for the food and beverage industry. Both companies offer certification of equipment’s resistance to cleaning agents. These certificates are not prescribed by law and are frequently used in the segments as proof of stability.

The washdown component must also be easy and safe to clean. However, unlike the hygienic design, fixing holes, edges and threads are permitted here.

For basic information on IP69K see also this previous blog post.

To learn more about solutions for washdown and hygienic design click here.


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The Perfect Photoelectric Sensor – Imagine No More

In my last blog, Imagine the Perfect Photoelectric Sensor, I discussed the possibilities of a single part number that could be configured for any of the basic sensing modes: through-beam, retroreflective, background suppression and diffuse. This perfect sensor would also have the ability to change the sensing mode on the fly and download the required parameters for a changing process or format change.  Additionally, it would have the ability to teach the sensing switch points on the fly, change the hysteresis, and have variable counter and time delays.


Tomorrow is here today! There is no need to imagine any longer, technology has taken another giant leap forward in the photoelectric world.  Imagine the possibilities!

Below are just some of the features of this leading edge technology sensor. OEM’s now have the opportunity to have one sensor solve multiple applications.  End users can now reduce their spare inventory.

To learn more visit


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Increase Competitiveness with RFID in the Intralogistics Industry

In times of globalization and high labor costs it is a challenge to increase competitiveness in the fashion industry. Within a warehouse, an RFID system supports a high degree of automation as well as short transport distances. To supply dealers and to keep their facility profitable, one of the most successful fashion companies in the world has built a highly modern hanging garment distribution center. Let’s take a look at how they successfully implemented RFID technology to improve their processes.

Separate and sort clothes with just one hybrid module (2D code + RFID)

Within this distribution center 45,000 of these innovative clothes hanger adapters (L-VIS) are used. They replace the previous trolley-based logistics approach by allowing the transportation of a number of different garments that have the same destination.


L-VIS, clothes hanging adapter made by P.E.P. Fördertechnik

With the investment in some additional space in the so-called buffer or storage zone, and by providing empty trolleys at various locations to keep the product flow moving, this project is successfully accomplished. A major advantage of this system, is the usability over the entire intralogistics chain. From receiving, to the hanging storage, to the sorter for single item identification, and from there as a transport unit to shipping.

The clothes hanger contains an RFID chip, that is automatically read by the conveying technology, and the 2D-code. This code is read manually by employees with a portable acquisition unit. The code can be DMC (Data Matrix Code), QR-Code, or any other optical code standard.


HUGO BOSS garment distribution center (Metzingen, Germany)

Information exchange without visual contact

A high frequency RFID chip is installed. With this identification system, neither direct alignment nor contact is needed to enable data exchange via nearfield communication. Non-contact identification is extremely reliable and wear-free. The identification system consists of a rugged data carrier, a read/write head and an RFID processor unit. The processor unit communicates to the control system via Profibus, but could be accomplished with ProfiNet or EtherNet/IP as well.


BIS-M RFID processor unit

The following table gives you an overview of types of Radio Frequency Identification solutions that are available on the market:

Common Types Low Frequency Low Frequency High Frequency Ultra High Frequency
Frequency 70/455 kHz 125 kHz 13.56 MHz 860 … 960 MHz
Short description Dedicated solution to tool identification in Metal-Working industry. Standard solutions for simple Track & Trace applications. Fast & reliable – even with high volumes of data in medium distances in assembly, production and intralogistics. Identification at large distances and bunching capability for current material flow concept.

For the customer, the decision to choose this particular system among others was the separation between the processor and read/write head. In a widespread facility it would not make sense to have a decoder with 30 read/write heads attached. By interfacing two read/write heads per processor, it is possible to track the travel of a transport unit over the entire conveyor line as well as track within the aisles between the individual shelves.

An additional advantage of the system implemented is the housing options. The L-VIS carrier and the 30 mm read/write head are an ideal match. The simple mounting of the processors and ready-to-use connection were of high value to the system integrators. In the sorting area, a 2D code was supplemented by the RFID tags to reach speeds of up to 0.6 and 0.7 m/s. This would probably not have been possible with the installation of a corresponding camera technology.

Experiences have shown, that RFID projects need a lot of support. Consultation and assistance from true experts can be provided by our team. Learn more about RFID technology here.

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An Easy Way to Remember PNP and NPN Sensor Wiring

Here’s a simple way remember how to wire up a 3-wire DC PNP or NPN sensor:

PNP = Switched Positive

NPN = Switched Negative

“Switched” refers to which side of the controlled load (relay, small indicator, PLC input) is being switched electrically. Either the load is connected to Negative and the Positive is switched (PNP), or the load is connected to Positive and the Negative is switched (NPN). These diagrams illustrate the differences between the two connections.

Click here for more information about the Basics of Automation.

2.14.2018_PNP v NPN Graphic


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The Human Body as an Analogy for Automation

A machine’s automation system operates very much like the human body. Just as we humans perceive our surroundings using our sensory organs, a machine registers its surroundings using presence sensors, input devices, and measuring systems. It continually receives status information and command inputs, and its control network transports this information as input signals to the controller. The controller interprets these signals, makes a program decision, and responds by sending output signals to actuators and indicators. For example, it may send a signal to cylinder valves and motor drives to move the machine, or to stack lights to signal status and condition to the human operators.

A machine’s automation system is the technical counterpart to the actions of the human body:

  • Sight, taste, smell, touch – Vision, pressure, temperature, flow, photoelectric, inductive, capacitive, position/distance measurement sensors
  • Listening/reading – Vibration sensors, RFID tag readers
  • Nervous system – Control network, cables, connectors
  • Brain – Controller, PLC
  • Muscles – Valves, drives, motors
  • Voice – audio signaling devices, numerical output devices (RFID data to tag)
  • Body language (visual signals) – stack lights, display screens, indicator lights, panel meters

Check out the video below to dive deeper into the world of industrial automation and learn the similarities between a machine and the human body.


Stay tuned for future posts that will cover the essentials of automation. To learn more about the Basics of Automation in the meantime, visit

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Clamp Control of Tools and Workpieces

In Metalworking, the clamping status of tools and workpieces are monitored in many Image1applications. Typically, inductive sensors are used to control this.

Three positions are usually detected: Unclamped, clamped with object, and clamped without object. The sensor position is mechanically adjusted to the application so the correct clamping process and clamping status is detected with a proper switch point. Additionally, with the usage of several sensors in many cases the diagnostic coverage is increased.

For approximately 15 years, inductive distance sensors with analog output signals have been utilized in these applications with the advantage of providing more flexibility.

 Image2By using a tapered (conical) shape, an axial movement of the clamping rod can be sensed (as a change of distance to the inductive sensor with analog output). Several sensors with binary (switching) output can be replaced with a sensor using such a continuous output signal (0..10V, 4-20 mA or e.g. IO-Link). Let’s figure a tool in a spindle is replaced by another tool with a different defined clamping position. Now, rather than mechanically changing the mechanical position of the inductive sensor with binary output, the parameter values for the correct analog signal window are adjusted in the control system. This allows easy parameter setting to the application, relevant if the dimensions of the clamped object may vary with different production lots.

The latest state-of-the-art sensor solution is the concept of a compact linear position system which is built of several inductive sensor elements mounted in one single housing. Image3

Instead of a tapered (conical) shape, a disk shaped target moves lateral to the sensor. From small strokes (e.g. 14 mm) up to more than 100 mm, different product variants offer the best combination of compact design and needed lateral movement. Having data about the clamping force (e.g. by using pressure sensors to monitor the hydraulic pressure) will lead to additional information about the clamping status.

For more information on linear position sensors visit

For more information on pressure sensors, visit


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Back to the Basics: What is the Value of IO-Link?


With the demands for flexible manufacturing, efficient production & visibility in our factories, smart manufacturing is driving the way we work today.  Analytics and diagnostics are becoming critical to our ability to perform predictive maintenance, improve equipment effectiveness and monitor the condition of the machine as well as the components inside the machine.  Typically, our first reaction is to put these devices onto Ethernet.  However, the implementation of Ethernet requires a high skill set that is scarce in our traditional manufacturers today.  Due to the simple control architecture of IO-Link devices, it allows for many Smart devices to provide the data we need for analytics with a reduction in the Ethernet skill set that has become a roadblock for many manufacturers.

Many people think IO-Link is a new industrial network to compete with EtherNet/IP or Profinet, but this is a common misconception. IO-Link is complementary to those networks and typically enables those networks to do even more than previously thought.

Standard IO-Link Setup_01_preview

Open Standard

IO-Link is an open standard designed with the idea to act like USB for industrial automation.  IO-Link is meant to simplify the smart sensor & intelligent device connectivity on the factory floor in a similar way that USB simplified connectivity to computers for auxiliary devices.  IO-Link is not an industrial network or fieldbus; it is an industrial network and industrial controller agnostic. Designed with a master to slave configuration, addressing of the devices is point-to-point, similar to USB.  Compatible IO-Link masters can act as slaves or nodes on a variety of industrial protocols and act complementary to the network of the user’s choosing.  Eliminating the need for serial communication configuration or network addressing simplifies the connection and integration of devices.

Value in Machine Builds

IO-Link has advantages for both machine io-link master_18x18_300dpibuilders and discrete manufacturers.  For machine builders, the biggest advantage comes from the simplified wiring scheme of IO-Link devices.  We have seen machine builder users of IO-Link reduce their wiring hardware & labor costs by 30%-60% for sensors,
outputs & controls.  This is realized with the simple sensor tool cords used for connections, quick-disconnect connectors on the cables and machine mount Ethernet masters devices.  It is also realized for machine builders in an increase of turns on their floor, a reduction in build labor and significantly faster commissioning time.

Value on the Production Floor

For discrete manufacturers, the biggest advantages have come from the parameterization and diagnostic features on the IO-Link devices.  With the ability to store & send parameters between the master & slave, IO-Link devices can be automatically configured. Hot-swapping a complex smart device like a pressure sensor can go from a stressful ordeal including 14-plus setpoints to literally a push of one button.  Combining this functionality with multiple diagnostics both in the master & slaves eliminates human error and dramatically reduces downtime & troubleshooting for manufacturers.

To learn more about market leading IO-Link technologies, visit

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Top 5 Automation Insights Posts from 2017

Kick off the New Year by taking a look at the top 5 Automation Insight blog posts from last year.

#5. Make sure your RFID system is future-proof by answering 3 questions

With the recent widespread adoption of RFID technology in manufacturing plants I have encountered quite a number of customers who feel like they have been “trapped” by the technology. The most common issue is their current system cannot handle the increase in the requirements of the production line. In a nutshell, their system isn’t scalable.5

Dealing with these issues after the fact is a nightmare that no plant manager wants to be a part of. Can you imagine installing an entire data collection system then having to remove it and replace it with a more capable system in 3 years or even less? It’s actually a pretty common problem in the world of technology. However, an RFID system should be viable for much longer if a few simple questions can be answered up front. Read more>>

#4. IO-Link Hydraulic Cylinder Position Feedback

Ready for a better mousetrap?  Read on…..

Some time ago here on Sensortech, we discussed considerations for choosing the right in-cylinder position feedback sensor.  In that article, we said:

“…….Analog 0-10 Vdc or 4-20 mA interfaces probably make up 70-80% of all in-cylinder feedback in use…..”


And while that 70-80% analog figure is still not too far off, we’re starting to see those numbers decline, in favor a of newer, more capable interface for linear position feedback:  IO-Link.  Much has been written, here on Sensortech and elsewhere, about the advantages offered by IO-Link.  But until now, those advantages couldn’t necessarily be realized in the world of hydraulic cylinder position feedback.  That has all changed with the availability of in-cylinder, rod-style magnetostrictive linear position sensors.  Compared to more traditional analog interfaces, IO-Link offers some significant, tangible advantages for absolute position feedback in hydraulic cylinders. Read More>>

#3. External Position Feedback for Hydraulic Cylinders

The classic linear position feedback solution for hydraulic cylinders is the rod-style magnetostrictive sensor installed from the back end of the cylinder. The cylinder rod is gun-drilled to accept the length of the sensor probe, and a target magnet is installed on the face of the piston. A hydraulic port on the end cap provides installation access to thread-in the pressure-rated sensor tube. This type of installation carries several advantages but also some potential disadvantages depending on the application. Read More>>


#2. 3 Smart Applications for Process Visualization

Stack lights used in today’s industrial automation haven’t changed their form or purpose for ages: to visually show the state (not status) of the work-cell. Since the introduction of SmartLight, I have seen customers give new2 meaning to the term “process visualization”. Almost every month I hear about yet another innovative use of the SmartLight. I thought capturing a few of the use-cases of the SmartLight here may help others to enhance their processes – hopefully in most cost effective manner.

The SmartLight may appear just like another stack-light.  The neat thing about it is that it is an IO-Link device and uses simply 3-wire smart communication on the same prox cable that is used for sensors in the field. Being an IO-Link device it can be programmed through the PLC or the controller for change of operation modes on demand, or change of colors, intensity, and beeping sounds as needed. What that means is it can definitely be used as a stack light but has additional modes that can be applied for all sorts of different operation/ process visualization tasks. Read More>>

#1. What is a Capacitive Sensor?

Capacitive proximity sensors are non-contact devices that can detect the presence or absence of virtually any object regardless of material.  1They utilize the electrical property of capacitance and the change of capacitance based on a change in the electrical field around the active face of the sensor.

A capacitive sensor acts like a simple capacitor.  A metal plate in the sensing face of the sensor is electrically connected to an internal oscillator circuit and the target to be sensed acts as the second plate of the capacitor.  Unlike an inductive sensor that produces an electromagnetic field a capacitive sensor produces an electrostatic field. Read More>>

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IO-Link Measurement Sensors Solve Application Challenges

In industrial distance and position measurement applications, one size definitely does not fit all.  Depending on the application, the position or distance to be measured can range from just a few millimeters up to dozens of meters.  No single industrial sensor technology is capable of meeting these diverse requirements.

Fortunately, machine builders, OEM’s and end-users can now choose from a wide variety of IO-Link distance and position measurement sensors to suit nearly any requirement.  In this article, we’ll do a quick rundown of some of the more popular IO-Link measurement sensor types.

(For more information about the advantages of IO-Link versus traditional analog measurement sensors, see the following blog posts, Solving Analog Integration Conundrum, Simplify Your Existing Analog Sensor Connection, and How Do I Make My Analog Sensor Less Complex?)


Short Range Inductive Distance Sensors

These sensors, available in tubular and blockScott Image1.JPG style form factors are used to measure very short distances, typically in the 1…5 mm range.  The operating principle is similar to a standard on/off inductive proximity sensor.  However, instead of discrete on/off operation, the distance from the face of the sensor to a steel target is expressed as a continuously variable value.  Their extremely small size makes them ideal for applications in confined spaces.

Inductive Linear Position Sensors

Inductive linear position sensors are available in several block style form factors, and are used for position measurement over stroke lengths up to about 135 mm.  These types of sensors use an array of inductive coils to accurately measure the position of a metal target.  Compact form factors and low stroke-to-overall length factor make them well suited for application with limited space.


Magnetostrictive Linear Position Sensors

IO-Link Magnetostrictive linear position sensors are available in rod style form factors for hydraulic cylinder position feedback, and in external mount profile form factors for general factory automation position monitoring applications.  These sensors use time-proven, non-contact magnetostrictive technology to provide accurate, absolute position feedback over stroke lengths up to 4.8 meters.

Laser Optical Distance Sensors


Scott Image 4.JPGLaser distance sensors use either a time-of-flight measuring principle (for long range) or triangulation measuring principle (for shorter range) to precisely measure sensor to target distance from up to 6 meters away.  Laser distance sensors are especially useful in applications where the sensor must be located away from the target to be measured.


Magnetic Linear Encoders

IO-Link magnetic linear encoders use an absolute-codedScott Image 5 flexible magnet tape and a compact sensing head to provide extremely accurate position, absolute position feedback over stroke lengths up to 8 meters.  Flexible installation, compact overall size, and extremely fast response time make magnetic linear encoders an excellent choice for demanding, fast moving applications.

IO-Link Measurement Sensor Trends

The proliferation of available IO-Link measurement sensors is made possible, in large part, due to the implementation of IO-Link specification 1.1, which allows faster data transmission and parameter server functionality.  The higher data transfer speed is especially important for measurement sensors because continuous distance or position values require much more data compared to discrete on/off data.  The server parameter function allows device settings to be stored in the sensor and backed up in the IO-Link master.  That means that a sensor can be replaced, and all relevant settings can be downloaded from master to sensor automatically.

To learn about IO-Link in general and IO-Link measurement sensors in particular, visit

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