When is a Weld Field Immune Sensor Needed?

When the topic of welding comes up we know that our application is going to be more challenging for sensor selection. Today’s weld cells typically found in tier 1 and tier 2 automotive plants are known to have hostile environments that the standard sensor cannot withstand and can fail regularly. There are many sensor offerings that are designed for welding including special features like Weld Field Immune Circuitry, High Temperature Weld Spatter Coatings and SteelFace Housings.

For this SENSORTECH topic I would like to review Weld Field Immune (WFI) sensors. Many welding application areas can generate strong magnetic fields. When this magnetic field is present a typical standard sensor cannot tolerate the magnetic field and is subject to intermittent behavior that can cause unnecessary downtime by providing a false signal when there is no target present. WFI sensors have special filtering properties with robust circuitry that will enable them to withstand the influence of strong magnetic fields.

WFIWFI sensors are typically needed at the weld gun side of the welding procedure when MIG welding is performed. This location is subject to Arc Blow that can cause a strong magnetic field at the weld wire tip location. This is the hottest location in the weld cell and typically there is an Inductive Sensor located at the end of this weld tooling.

So as you can see if a WFI sensor is not selected where there is a magnetic field present it can cause multiple cycle time problems and unnecessary downtime. For more information on WFI sensors click here.

There’s more than just one miniature sensor technology

As I discussed in my last blog post, there is a need for miniature, precision sensors. However, finding the right solution for a particular application can be a difficult process. Since every sensor technology has its own strengths and weaknesses, it is vital to have a variety of different sensor options to choose from.

The good news is that there are several different technologies to consider in the miniature, precision sensor world. Here we will briefly look at three technologies: photoelectric, capacitive, and inductive. Together these three technologies have the ability to cover a wide range of applications.

Photoelectric Sensors

MiniPhotoelectricPhotoelectric sensors use a light emitter and receiver to detect the presence or absence of an object. This type of sensor comes in different styles for flexibility in sensing. A through-beam photoelectric is ideal for long range detection and small part detection. Whereas a diffuse photoelectric is ideal for applications where space is limited or in applications where sensing is only possible from one side.

Miniature photoelectric sensors come with either the electronics fully integrated into the sensor or as a sensor with separate electronics in a remote amplifier.

Capacitive Sensors

MiniCapacitiveCapacitive sensors use the electrical property of capacitance and work by measuring changes in this electrical property as an object enters its sensing field. Capacitive sensors detect the presence or absence of virtually any object with any material, from metals to powders to liquids. It also has the ability to sense through a plastic or glass container wall to detect proper fill level of the material inside the container.

Miniature capacitive sensors come with either the electronics fully integrated into the sensor or as a sensor with separate electronics in a remote amplifier.

Inductive Sensors

MiniInductiveInductive sensors use a coil and oscillator to create a magnetic field to detect the presence or absence of any metal object. The presence of a metal object in the sensing field dampens the oscillation amplitude. This type of sensor is, of course, ideal for detecting metal objects.

Miniature inductive sensors come with the electronics fully integrated into the sensor.

One sensor technology isn’t enough since there isn’t a single technology that will work across all applications. It’s good to have options when looking for an application solution.

To learn more about these technologies, visit www.balluff.us/minis

Liquid Level Sensing: Detect or Monitor?

Pages upon pages of information could be devoted to exploring the various products and technologies used for liquid level sensing and monitoring.  But we’re not going to do that in this article.  Instead, as a starting point, we’re going to provide a brief overview of the concepts of discrete (or point) level detection and continuous position sensing.

 Discrete (or Point) Level Detection

Example of discrete sensors used to detect tank level

Example of discrete sensors used to detect tank level

In many applications, the level in a tank or vessel doesn’t need to be absolutely known.  Instead, we just need to be able to determine if the level inside the tank is here or there.  Is it nearly full, or is it nearly empty?  When it’s nearly full, STOP the pump that pumps more liquid into the tank.  When it’s nearly empty, START the pump that pumps liquid into the tank.

This is discrete, or point, level detection.  Products and technologies used for point level detection are varied and diverse, but typical technologies include, capacitive, optical, and magnetic sensors.  These sensors could live inside the tank outside the tank.  Each of these technologies has its own strengths and weaknesses, depending on the specific application requirements.  Again, that’s a topic for another day.

In practice, there may be more than just two (empty and full) detection points.  Additional point detection sensors could be used, for example, to detect ¼ full, ½ full, ¾ full, etc.  But at some point, adding more detection points stops making sense.  This is where continuous level sensing comes into play.

Continuous Level Sensing

Example of in-tank continuous level sensor

Example of in-tank continuous level sensor

If more precise information about level in the tank is needed, sensors that provide precise, continuous feedback – from empty to full, and everywhere in between – can be used.  This is continuous level sensing.

In some cases, not only does the level need to be known continuously, but it needs to be known with extremely high precision, as is the case with many dispensing applications.  In these applications, the changing level in the tank corresponds to the amount of liquid pumped out of the tank, which needs to be precisely measured.

Again, various technologies and form factors are employed for continuous level sensing applications.  Commonly-used continuous position sensing technologies include ultrasonic, sonic, and magnetostrictive.  The correct technology is the one that satisfies the application requirements, including form factor, whether it can be inside the tank, and what level of precision is needed.

At the end of the day, every application is different, but there is most likely a sensor that’s up for the task.

Customization of RFID tag holders and mounting accessories

Does your RFID application require a customized tag holder? What about special brackets for read/write heads and processors? Don’t have the bandwidth to design the mounting hardware required for your unique application? The Balluff Customizing Group can help! If you are implementing the BIS C, BIS L, BIS M or BIS U RFID systems we will make sure you get the performance your application demands.

For several years the Balluff Customizing Group has been working directly with engineers and maintenance personal to provide design and development services for RFID mechanical accessories. The process is streamlined and very straight forward. Please contact Balluff’s Technical Support Professionals to discuss your RFID application.

Here are a few recent examples of RFID projects in the Customizing Group:

1) RFID Pistol Grip Read/Write Head for BIS M data carriers. The modular design can be used with M12, M18 and M30 tubular read/write heads for logistics tracking of incoming and outgoing shipments.

PistolGrip

2) Keyfob with embedded BIS C data carrier. Individual access codes are programmed to the tags allowing only authorized personnel to enter restricted areas.

Keyfob Keyfob2

3) BIS M read/write data carriers embedded in stainless steel NPT plug for Production Tracking.

DataCarrier

5 Tips on Making End-of-Arm Tooling Smarter

Example of a Flexible EOA Tool with 8 sensors connected with an Inductive Coupling System.

Example of a Flexible EOA Tool with 8 sensors connected with an Inductive Coupling System.

Over the years I’ve interviewed many customers regarding End-Of-Arm (EOA) tooling. Most of the improvements revolve around making the EOA tooling smarter. Smarter tools mean more reliability, faster change out and more in-tool error proofing.

#5: Go Analog…in flexible manufacturing environments, discrete information just does not provide an adequate solution. Analog sensors can change set points based on the product currently being manufactured.

#4: Lose the weight…look at the connectors and cables. M8 and M5 connectorized sensors and cables are readily available. Use field installable connectors to help keep cable runs as short as possible. We see too many long cables simply bundled up.

#3: Go Small…use miniature, precision sensors that do not require separate amplifiers. These miniature sensors not only cut down on size but also have increased precision. With these sensors, you’ll know if a part is not completely seated in the gripper.

#2: Monitor those pneumatic cylinders…monitoring air pressure in one way, but as speeds increase and size is reduced, you really need to know cylinder end of travel position. The best technology for EOA tooling is magnetoresistive such as Balluff’s BMF line. Avoid hall-effects and definitely avoid reed switches. Also, consider dual sensor styles such as Balluff’s V-Twin line.

#1: Go with Couplers…with interchangeable tooling, sensors should be connected with a solid-state, inductive coupling system such as Balluff’s Inductive Coupler (BIC). Avoid the use of pin-based connector systems for low power sensors. They create reliability problems over time.

Consider this when using multi-vendor IO-Link solutions

The IO-Link consortium allows for multiple master connections from DIN rail slice IP20 solutions to IP67 ports.  As usage of IO-Link has grown dramatically over the last two years and adoption of multi-vendor solutions continues to rise, there will be a point where you may encounter an alternate type of IO-Link connection for IP67 masters and devices in the market.

The specification allows for a wide variety of connectors and conductors for the IO-Link master/slave connection specifically calling out M5, M8 & M12 connectors.  The default port and pin configuration for an IO-Link master port is the M12 A-coded connection with port type A.  In IO-Link port A, the power for the IO-Link slave device is provided entirely by the pins 1&3 similar to a standard proximity sensor according to IEC 61076-2-101.  This is the most common port type in use today and is found on the widest variety of sensors and slave devices.

An alternate port type is available, IO-Link Port B, to provide galvanically isolated power to the IO-Link slave device.  In this configuration a second power supply can be added for isolated control power.  It is not widely adapted in IO-Link slave devices today but can be found in some products where this is an application requirement.  If a master or device has a port type B it must be clearly labelled on the product per the specification.

PortAPortB

If there is not a port type identified on the device then it is assumed to be a port A type device as it is the default configuration.  Balluff IO-Link masters and devices are mostly of the type port A.  Check out Balluff’s IO-Link offering.

 

Certifiably Confusing: Hazardous Area Certifications

“This is your last chance. After this, there is no turning back. You take the blue pill – the story ends, you wake up in your bed and believe whatever you want to believe. You take the red pill – you stay in Wonderland and I show you how deep the rabbit-hole goes.”

                              - “Morpheus” as played by Lawrence Fishburne in The Matrix

The first time you come into contact with the subject of hazardous area certifications, you may feel like you have chosen to take the red pill.  The topic starts off being complex, and the more you study it the more bewilderingly complex it becomes.

There are people who have devoted their entire careers to studying and learning the intricacies of hazardous area certifications and have become legitimate experts in the topic, so this short blog entry will not even attempt to offer up a comprehensive treatment.  But hopefully we can orient the newcomer to the subject with some context and provide some clues about where to start looking for more information.

Why Hazardous Area Certification?

Industrial processes must often be conducted in the presence of dangerous atmospheres or materials such as explosive gases, combustible dusts, or flammable liquids.  These substances can be ignited by sufficient energy coming from sources like electrical sparks, open flames, and hot surfaces.  Electrical equipment installed in these areas needs to be designed with some kind of methodology to prevent that equipment from becoming a source of ignition.  In most countries around the world, national and/or local governments enact electrical construction standards intended to prevent accidents and enhance the safety of people and property.  In order to ensure that installed equipment is competently designed and tested to provide the necessary level of protection, third-party agencies or “notified bodies” exist to certify that a particular piece of equipment meets the highly specialized design and performance standards for hazardous locations.

Protection Methods

Depending on the nature of the hazard and the type of electrical equipment, different protection methods – design concepts – may be deployed.  Ranked from basic to more costly, commonly these include:

  • Enhanced Safety
    • A simple level of protection intended for situations where the hazard is low and/or very rarely or intermittently present. Typically it consists of a housing with liquid-resistant sealing and gaskets that will also block the entry of gases for a limited period of time.
  • Intrinsic Safety
    • This method relies on limiting the amount of available energy in the electrical circuit to a very low threshold, such that a short or open circuit is not able to generate an electrical spark sufficiently energetic to cause ignition. It is inherently – intrinsically – safe.
  • Flameproof or Explosion Proof Housings
    • Similar approaches with different names depending on the standard being applied, the idea is to construct a robust and well-sealed enclosure around the electrical components. In the event that, for example, gases somehow get inside the enclosure and ignition occurs, the hot gases of combustion are contained inside the housing. Any gases that are vented must travel an intentionally long path that cools them to a temperature that is safe for the type of hazard present outside the enclosure.
  • Air Purge
    • Typically used for large enclosures containing power components such as circuit breakers, relays, or motor starters as well as instrumentation & control panels that contain electronic components in light-duty, unsealed housings. A positive pressure is maintained inside the large enclosure at all times to deliver fresh purge air into the enclosure and prevent the entry of hazardous gases.

Hazardous Area Classification

There are many types and categories of hazards that exist, with different levels of combustibility and different probabilities that the hazard is present.  How these areas are classified depends on the country or region where the installation will take place.  In the United States, the National Electrical Code (NEC) governs the classification of hazardous locations under two methodologies: the Class/Division system or the Zone system.  The Class/Division system is traditional in the US and the Zone system is a newer, alternative concept that is gaining wider acceptance.  Once a decision is made for a particular facility about which system will be implemented, that system is then consistently applied throughout the installation.  Canada is similar to the US but follows the Canadian Standards Association (CSA) electrical codes.  In the European Union, hazardous locations are governed by a CE (Conformité Européenne) standard called ATEX (ATmosphere EXplosive).  For the rest of the world, there may be a variety of local codes and standards, but increasingly many countries are adopting a uniform global standard called International Electrotechnical Commission Explosive or IECEx for short.  In some cases a country may accept IECEx as a basis standard and still require additional national certification for specific in-country requirements.

Selecting the Right Equipment Certification

Starting with the country where the equipment will be installed, the relevant national standards are identified.  The hazard must then be classified by an expert according to that standard.  Then the nature and type of equipment is considered and the type of protection methods that are available.  The right equipment certification is one that:

  • Is appropriate for the country where the equipment is being applied
  • Is appropriate for the classification of the hazard
  • Is appropriate for the type of equipment being installed and the relevant protection methods available

Finally, different equipment manufacturers may choose to have their products certified by different third-party agencies.  As long as the certifying body applies all of the relevant national standards and requirements, then the certifications or “approvals” provided by different agencies are essentially equivalent to one another from an electrical code / legal perspective.

Some Common Hazardous Location Symbols and Links

Factory Mutual “FM”  (US/Canada)

FactoryMutual

CSA (US/Canada)

 CSA

 Underwriters’ Laboratories “UL” (US/Canada)

UL

ATEX (European Union)

ATEX

IECEx (Worldwide)

IECEx

Navigating the Matrix

Clearly, there is a lot to know when it comes to hazardous area certifications.  As a potential buyer or specifier of equipment just trying to complete a job, it all may seem a bit overwhelming. Fortunately, you’re not stuck out there trying to go it alone. Your best bet for help in choosing the right gear is to start with the equipment manufacturer. No one is more familiar with the product and the scope of its appropriate installations, so they can offer expert knowledge and experienced guidance regarding the proper application of the equipment. And if there’s something they don’t know, they can find out for you or facilitate putting you in touch with additional resources for assistance.

Interested in valve actuator position feedback for hazardous locations?  Balluff’s TA12 linear position sensor carries world-wide certifications.

Barcode and RFID, A one-two punch when it comes to sequencing

UHFRFIDAll too often I read about RFID replacing barcode as an ID technology. No doubt, there are cases where RFID is used to replace a barcode system due to a harsh environment or there is a need to “de-centralize” information etc., but more often than not I see both barcode and RFID being used together to address an application. It doesn’t have to be one or the other.

One application where the two live in harmony is sequencing. Sequencing is referred to by many different names and acronyms and is synonymous with automotive assembly plants and their tier suppliers. In a nutshell, the goal is to deliver the exact number of components in the exact order they will be used. When this is done efficiently the result is a WIN-WIN-WIN. A win for the supplier because they decrease the amount of in-process inventory and carrying costs; A win for the manufacturer because they maximize their floor space and spend less time hunting parts and components to complete a build; And a win for the consumer because they get their new car faster.

As one can imagine there is a great deal of communication and data sharing that must take place in order for this to operate smoothly. This is where the one-two punch of RFID and barcode come into play. The most common method is to identify the parts with barcodes and write the barcode data to the RFID tag which is fixed to the carrier. The information on the RFID tag identifies the carrier and identifies the components on the carrier. Rather than explain how this works, it makes more sense to look at a real-life example of how a major automotive supplier achieved their sequencing goals by using the one-two punch. Read Balluff’s Application Spotlight on UHF RFID Sequencing to learn more.

1 Visual Way to Improve Operator Performace

Many manufacturers I talk to are excited about the possibilities that our new Smart Light technology, used in level mode, brings to their production or machines.  Here’s a video if you havent seen it yet:

It works over virtually any industrial network with an open standard called IO-Link, which I’ve discussed many times in previous posts.

What I’m really impressed with is the number of people integrating the level mode as a quick and easy way to give instantaneous feedback to an operator on their performance to a quota or as a count-down timer.  Here you can see in the middle of the right photo a bright green bar light just to the left of the red kanban rack.  There are multiple of these lights in this image.

Tesla Motors Blog – Factory Upgrade

This light is a five zone Smart Light operating in level mode.  As the cycle time winds down, the light decreases in value until there is no more time, at that point it flashes bright red to notify the operator to cycle to the next vehicle.  It keeps the production on track and helps operators know quickly and easily how much time remains.  What I’ve been told is nice about this is how bright the light is and that it is easily install-able without a controls cabinet or slice i/o j-box like you can see in the photo.  Others like it because it makes the data visual from all over, where HMIs require you to stand right in front of them for information.

So if you are trying to think about ways to visualize data in your process or production to operators or managers, there are many others out there already using Smart Light for that application.  Check it out.

Trending Now: Miniature Sensors

Celebrating the Holiday season is one of my favorite times of the year. Some of the common activities I enjoy include spending time with family and friends, eating a tremendous amount of food (and wondering afterward why I do this to myself year after year), and giving and receiving a few presents. Let’s focus on the presents aspect for a second. The bigger the present the better, right? Well, we know that’s not always the case. That smaller present could very well be the perfect gift.

minifamilyNow let’s shift gears and look at manufacturing. There is a trend in manufacturing, in general, toward miniaturization. Earlier this year I was shown a website, MICRO Manufacturing, that looks across different industries to see how the miniaturization trend is being engaged. One of the more obvious cases is in consumer electronics. It all started taking off with the desktop computer. Following the desktop computer was the laptop. And in the past few years we’ve seen the rise of smartphones and tablets. Now we’re beginning to see smart wearable devices (watches, fitness trackers, glasses, etc.). Who knows what will happen next? I bet we could take a good guess: it’ll be something even smaller.

As manufacturing continues in this direction, the demand for miniature sensors grows. However, miniature sensors aren’t just defined by their small form factor, but also by their precision. Miniature sensors are developed with a clear purpose to meet these manufacturing requirements. For more information, please click here.

And, just like that small present during the Holidays, a miniature, precision sensor could be the perfect solution.

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