A superior non-contact sensing principle

MagnetostrictionImageMagnetostriction is a property of ferromagnetic (iron-based, magnetizeable) materials that causes them to change their shape or dimensions in the presence of a magnetic field. In addition to numerous other practical uses, this magnetostrictive effect is ideally suited for use in industrial linear position measurement sensors. Magnetostrictive linear position sensors use an iron-alloy sensing element, typically called a waveguide. Referring to the diagram at right, the waveguide (1) is housed inside a pressure-rated stainless steel tube or in an aluminum extrusion. The position magnet (2) is attached to the moving part of the machine, or the piston of a hydraulic or pneumatic cylinder. Measurements are initiated by applying a short-duration electrical pulse to a conductor (3) attached to the waveguide. The current creates a magnetic field (4) along the waveguide.

The magnetic field from the position magnet interacts with the generated magnetic field, inducing a torsional mechanical strain on the waveguide. When the current pulse stops, the strain is released, causing a mechanical pulse to propagate along the waveguide. This mechanical pulse travels at a constant speed, and is detected at the signal converter (5).

The time between the initial electrical pulse and the received mechanical pulse accurately represents the absolute position of the position magnet and, ultimately position of the machine or hydraulic cylinder. The position of the magnet along the waveguide is calculated by very accurately timing the interval between the initial current pulse, also known as the Interrogation Pulse, and the detection of the mechanical return pulse.

MagnetostrictionWaves

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Enabling the Visibility Provided by the Industrial Internet of Things

One of the promises of the Industrial Internet of Things (IIoT) and Industry 4.0 is the visibility provided to the manufacturing plant floor. But what information is important and from what type of field devices? So we asked those two questions to our most progressive group of customers…IO-Link users. These customers have realized the benefits of IIoT and I4.0 through the enabling technology of IO-Link.

Visibility-of-things-whiteThe included Infographic displays the most valuable information from the most critical devices.  Not surprising that predictive maintenance information is viewed as the most critical. Examples of this would include sensors getting dirty or out of adjustment but still operational for the time being. Interestingly, firmware revision control made the top of the list. This appears to be a growing trend as more and more field devices have microprocessors creating revision control issues.

As for the devices, measurement products were on the top of the list. That’s understandable as these products tend to be more costly and complex with parameter and calibration information. Most interesting were the good-old power supplies. These hard working, often forgotten products are critical, but obviously few people are concerned about how they are functioning. This could also be due to the fact that there are not many viable products on the market.

Whether you’re a seasoned professional with IIoT and I4.0 or just looking at the possibilities, the enabling technology of IO-Link is here now. And better yet, it’s scalable to your needs. Have a look today at www.balluff.us/io-link.

 

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The Latest Trend in the Stamping and Die Industry

compact-sensor-blogOne trend we see today in many applications is the need for smaller low profile proximity sensors. Machines are getting much smaller and the need for error proofing has ultimately become a must for such applications in the Stamping and Die industry. Stamping Die processes can be a very harsh environment with excessive change overs to high speed part feed outs when running production. In many cases these applications need a sensor that can provide 5mm of sensing range however they simply do not have the room for an M18 sensor that is 45 to 50mm long. This is where the “FlatPack” low profile sensor can be a great choice due to their low profile dimensions.

Proximity sensors have proven time and time again to reduce machine crashes, part accuracy and proper part location. Sensors can be placed in multiple locations within the application to properly error proof “In Order Parts” (IO) for example detecting whether a punched hole is present or not present to ensure a production part is good. All of this adds up to reduced machine downtime and lower scrap rates that simply help a plant run more efficiently.

So when selecting proximity sensors and mating cables it is very important to select a sensor that A) mechanically fits the application and B) offers enough sensing range detection to reliably see the target without physical damage to the sensor. Remember, these sensors are proximity sensors not positive machine stops. Cables are also key to applications, it is important to pick a the proper cable needed for example an abrasion resistant cable may be needed due to excessive metal debris or a TPE cable for high flex areas.

Below both sensors have 5mm of sensing range:

M18vsFlatpack

Below both sensors have 2mm of sensing range:

M8vsFlatpack

You can see that in certain process areas “FlatPack” low profile sensors can provide benefits for applications that have space constraints.

For more information on proximity sensors click here.

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Mission Industry 4.0 @Balluff

Internet of Things (IoT) is the most discussed topic these days. Every organization, rather, every individual seems to have vast and varied definitions for what IoT means to them. In general all definitions revolve around connected-ness or interoperability of differing systems to make sense of plethora of data streaming from devices and machines at all levels. This grand vision attempts to connect individual consumers to the production value chain to provide the never-before-seen customized product experience.

Industrial Internet of Things (IIoT) is a small subsection of the grand vision– which in itself is huge visionary concept- that foresees the next generation of industrial automation. German government termed it as Industry 4.0 initiative, while in North America various organizations started initiatives such as Smart Factory, Connected Enterprise, Machine Clouds and so on.

At Balluff it took us almost a year to really break down the vague concept of IIoT and to define what would Industry 4.0 mean to us. We decided that it is not important what we think of Industry 4.0 rather it is important to understand what our customers expect of Industry 4.0 and we must find our path and our solution to help our customers realize their expectations of the modern factory. This definition should serve as a blue-print for our future product development and also utilize existing products to realize several concepts of the Industry 4.0.

Two major themes came to light that our customers valued the most and demand industry 4.0 framework to solve: Lot size one a.k.a. individualization of products, and, efficient production. In the current generation of automation we are focusing on small batch productions- for example, along the same production line we are dealing with multiple product variations or packaging but we produce many of the same kind. In the near future, each product while flowing through the line could be customized to individual’s taste- like the Coke bottle with your name on it.  Efficient production on the other hand is broader topic. Today we deal with efficiency at the plant level or machine level- with the added complexity of product customization, we need to broaden our horizons to production levels and efficiency of the entire organization to be able to produce where it is economical without compromising on any attributes of the product.

Industry4.0With our sensor, measurement and identification systems, combined with networking and connectivity solutions, we found ourselves at the core or the foundation layer of Industry 4.0 framework. Sensors and identification systems is where the data is essentially generated and flows through the connectivity solutions to the higher level systems to be interpreted and acted up-on. The actions/orders then flow back through the networks down to the devices and actuators to tune up the system performance. We essentially are the enablers or the Heartbeat of Industry 4.0! This means our sensors and systems need to talk intelligently and convey information beyond the sensing property. At Balluff we chose IO-Link as the intelligent communication across the board. It does not matter what the higher level communication is at the controller all our intelligent devices communicate over IO-Link, the medium that offers process, configuration and event communication on the single line.

With IO-Link at the foundation, our framework of Industry 4.0 consists of seven functional areas to provide sharp focus for our development and existing solutions: Predictive Maintenance, Parameterization, Recipe Change Management, Quality Assurance, Condition Monitoring, Format Change Management, and Traceability. These are the core areas that would assist us in helping our customers achieve their objectives.

Over next months, I will discuss each of these seven areas in greater details in my blogs.

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Recap of our top 5 posts of 2015

goodbye-2015-hello-2016As we wrap up the old and begin to open up the new, let’s take a moment to reflect on what this past year has brought us.  Apart from the triumphs and the hard lost battles, we want to bring you some of our top posts from 2015.  These posts are as follows:

#5: 5 Tips on Making End-of-Arm Tooling Smarter

Everyone wants their robot to work faster, smarter, and more efficiently.  In this post we review five easy tips to help you improve the efficiency of your end-of-arm tooling.

Example of discrete sensors used to detect tank level

Example of discrete sensors used to detect tank level

#4: Liquid Level Sensing: Detect or Monitor

Who doesn’t like complicated concepts broken down into easy to understand terminology? In this post we break down the differences between point level detection and continuous position sensing as well as provide you with technologies to put into practice.

#3: How Can I Convince My Boss to Send Me to Training?

As Aristotle once said “All men (and women) by nature desire knowledge.”  Here we are giving you the tools needed to break down the barriers your boss (or you) might have against investing in training.

#2: Back to the Basics: How Do I Wire a 2-Wire Sensor?

So you just got a brand spanking new 2-wire sensor for the holidays but you realize you don’t know exactly what wire goes where.  In this post we make wiring that bad boy easy and even break down what polarized and non-polarized mean.

So we have covered four of the top posts from 2015, are you ready for the number one post from the past year? So are we! And we will have it for you right after a quick message from our sponsors! (just kidding!)

power&dataexchange#1: Inductive Coupling – Simple Concept for Complex Automation

Through the use of magnetic induction, we are able to reduce the downtime of a machine due to the failure of a slip ring.  Inductive couplers pass power and data over an air gap creating a maintenance free, non-contact environment to operate a variety of machinery.

We want to thank you for the wonderful year that is behind us and be sure to be on the look-out for even more exciting news to come this year!

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Simplify Your Existing Analog Sensor Connection

In my last blog we reviewed how utilizing IO-Link sensors over analog sensors could be cost effective solution as it eliminates need for all the expensive analog I/O cards and shielded cables. In this blog we will see how IO-Link can effectively integrate your analog sensor- in case you want to retrofit your old sensor or maybe just because the IO-Link version for the sensor is not available.

Just to review few main points:

  1. Your beloved analog sensor typically requires a shielded cable run from the sensor to the control cabinet. The shielded sensor cables are usually 1.5x- 2x the cost of the standard M12 prox cables that you probably use elsewhere in the system.
  2. Where to connect the shielded cable? Now, you require analog card (typically 4 channel), which is also expensive compared to digital I/O cards — May be equally expensive as the IO-Link card. But, a 4 channel IO-Link master card could offer lot more compared to the 4-channel analog card. Simply put- your analog card can only take another 3 channels of analog signal where as there are a host of devices that you can connect to the IO-Link master to make your system scalable or future proof – more on this later- I get so excited talking about IO-Link.

In any case, coming back to the point- in general we pay a lot of money to add a single analog sensor in the system.  What if we could convert the analog signal to digital (same function that the analog card does), closer to the measurement sensor and get the digital data over a standard prox cable back to the control cabinet or to IO-Link? This way, we can totally eliminate or at least reduce the shielded cable run from sensor to the converter.

IO-Link3ConductorsBalluff offers this A/D converter module — at Balluff we refer to it as “Hobbit” – it is more like a small adapter that fits directly onto a sensor using the standard M12 fittings. The other side is M12 IO-Link connection to take the data back to the controller via an IO-Link master.  This single channel “Hobbit” offers 14 bits of conversion – to ensure you don’t lose data in translation.

IOLinkHubIf you need more than a single channel, Balluff also offers a 4-channel IO-Link hub, this still utilizes only a single port on the IO-Link master. Now, you have 3 or 7 ports (in case of 8 port IO-Link master), open to connect host of other devices such as digital I/O hubs, valve connectors, SmartLights, RFID, color sensors, Pressure sensors, linear measurement devices and so on…

I hope this blog helps you get little more clarity of many benefits of IO-Link. You can always learn more about the benefits of IO-Link at www.balluff.us/iolink.

On behalf of entire Balluff team, I want to wish you all Happy Holidays and Happy New Year!

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How Do I Make My Analog Sensor Less Complex?

So, you have a (or many) analog sensor in your application or system and they could be 4-20mA signal or 0-10V or even -10- +10V signal strength. You probably know that installing these specialty sensors takes some effort. You need shielded cables for signal transmission, the sensor probably has some digital interface for set-point settings or configuration. In all, there are probably 6-8 at minimum terminations for this single sensor. Furthermore, these expensive cables need to be routed properly to ensure minimal electromagnetic interference (EMI) on the wire. To make matter more complex, when its time to diagnose problem with the sensor, it is always on the back of your mind that may be the cable is catching some interference and giving improper readings or errors.

shieldedCablesOn the other hand, the cost side also is little tricky. You have the state of the art sensor that requires expensive shielded cable and the expensive analog input card (which generally has 4 channels- even if you use single channel), plus some digital I/O to get this single sensor to communicate to your PLC/PAC or controller. You are absolutely right, that is why people are demanding to have this sensor directly on their network so that it eliminates all the expensive cables and cards and talks directly to the controller on express way– so to speak.

Recently, there has been an explosion of industrial communication networks and fieldbuses. To name a few: EtherNet/IP, DeviceNet, PROFINET, PROFIBUS, CC-Link, CC-Link IE, Powerlink, Sercos, and the list goes on. As a machine builder, you want to be open to any network of customer’s choice. So, if that is the case, having network node on the sensor itself would make that sensor more bulky and expensive than before — but not only that, now the manufacturers have to develop sensor connectivity to ALL the networks and maintain separate inventory of each type. As a machine builder, it does put lot more stress on you as well to maintain different Bills of Materials (BOMs) for different projects – most likely – different sourcing channels and so on.

NetworksSo far what we discussed are two extremes; the way of the past with shielded cables and analog cards, and a wishful future where all devices are on the network. There is a middle ground that bridges yesterday’s method and the wishful future without adding any burden on manufacturers of the sensors or even the machine builders. The solution is IO-Link. IO-Link is the first standard (IEC 61131-9) sensor actuator communication technology. There are over 100+ members in the consortium that produce wide variety of sensors that can communicate over IO-Link.

If a sensor has IO-Link communication, denoted by  io-linklogo, then you can connect a standard M12 prox cable — let me stress– UNSHIELDED, to connect the sensor to the IO-Link port on the IO-Link master device. That’s it! No need to terminate connections, or buy expensive hardware. The IO-Link master device typically has 4, 8 or 16 ports to connect various IO-Link devices including I/O hubs, RFID, Valve connectors and more. (see picture below)

DistModIO

All signal communication and configuration now occurs on standard 3 conductor cable that you are currently using for your discrete sensors. The IO-Link master in turn acts as a gateway to the network. So, the IO-Link master sits on the network or fieldbus and collects all the sensors or discrete I/O information from devices and sends it to the controller or the PLC of the customer choice.

When your customer demands a different network or the fieldbus, the only thing that changes in your question is the master that talks to a different protocol.

In my next blog we will discuss how you can eliminate shielded cables and expensive analog cards for your existing analog sensor. Let me give you a hint– again the solution is with IO-Link.

You can learn more about IO-Link at www.balluff.us/iolink.

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Multiple Sensing Modes for Miniature Capacitive Sensors

MiniCapacitiveIn a previous blog post we discussed miniature capacitive sensors and their use for precision and small-part sensing. Here we will discuss the different sensing modes available with separately amplified miniature capacitive sensors.

 

Standard Switching Mode

Std_Switch_Mode

This is the most commonly used teach method for most sensing applications. As an object is placed statically in front of the sensor at its desired detection point, the amplifier is triggered to teach-in this value as its switch point (SP1). Once the value is taught, the output will then switch when the switch point is reached.

Two-Point Switching Mode

TwoPoint_Switch_Mode

As the name sug
gests this teach method has two separate teach-in points, a switch-on point (SP1) and a switch-off point (SP2). These points can be taught wide apart or close together, depending on the application need. One application example is for fill-level control by teaching in min. and max. fill-level points.

Window Function Mode

Window_Mode

This teach method creates a window between two separate switch points (SP1 and SP2). If the sensor value falls inside this window, the output will switch on. If the sensor value is outside of this window, the output remains off. An application example is material thickness (or multiple layer) detection. If the material is too thin or too thick (i.e., sensor value is outside the window) the output remains off; however, if the material is at the correct thickness (i.e., sensor value falls inside the window) the output switches on.

Dynamic Operation Mode

This mode only responds to moving objects and ignores static conditions. This mode is commonly used to ignore a close background, and only detect objects moving in front of the sensor.

Analog Output Mode
Analog_Mode

Additionally, an analog output (either voltage or current) is available. To utilize the whole analog range, two separate teach points are needed. SAHi, analog signal high, and SALo, analog signal low, are taught accordingly to obtain the full range. An application example would be continuous fill-level detection across the sensing area.

For more information on capacitive sensors and their remote amplifiers, click h
ere
.

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Back to Basics: The Fundamentals of a Passive RFID System

There has been a lot of talk in the industrial automation about RFID. In past blog posts we’ve discussed topics like RFID ROI and when to use IO-Link RFID. We could talk about things to consider when implementing RFID into your plant or different applications for days. In this entry, though, I’d like to get back to the basics a little bit.

Area of Application for a Passive RFID System:

RFID is used to accurately identify an object on which the tag is placed. In addition to identification, bject-specific information, like maintenance data is contained on the tag.

Typical RFID System

Typical RFID System

How It Works:

Since passive RFID tags contain no battery, the tag is powered up or “woke up” by the RF waves emitted from antenna of the same frequency. Once a tag is located in range it is powered up by the antenna and its memory can be read and transmitted to the processor. The time it takes the reader to extract information from the tag is usually measured in milliseconds.

Three Main Components of a Passive RFID System:


RFID-TagTag
– A combination of a chip and internal coil. The chip is where the data is held in the memory and can contain a few bytes of data or thousands of bytes of data depending on the capacity of the chip.

RFID-AntennaAntenna – Connected to the processor by an external cable or sometimes contained inside the same housing, the antenna transmits the data to and from the tag back through the processor

RFID-Processor Processor – The role of the processor is to organize the data as it is being read or written. The processor is usually connected to a controller, like a PC or PLC, and performs the task issued by the controller.

To learn more about industrial RFID applications and components visit www.balluff.us/rifd.

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Photoelectric Output Operate Modes and Output Types

Photoelectric sensors are used in a wide variety of applications that you encounter every day. They are offered in numerous housing styles that provide long distance non-contact detection of many different types of objects or targets. Being used in such a variety of applications, there are several outputs offered to make integration to control systems easy and depending on the sensing mode when the output is activated in the presence of the target.

DiffuseDiffuse sensors depend on the amount of light reflected back to the receiver to actuate the output. Therefore, Light-on (normally open) operate refers to the switching of the output when the amount of light striking the receiver is sufficient, object is present. Likewise, Dark-on (normally closed) operate would refer to the target being absent or no light being reflected back to the receiver.

RetroreflectiveRetroreflective and through-beam sensors are similar in the fact they depend on the target interrupting the light beam being reflected back to the receiver. When an object interrupts the light beam, preventing the light from reaching the receiver, the output will energize which is referred to as Dark-on (normally open) operate switching mode or normally open. Light-on (normally closed) operate switching mode or normally closed output in a reflex sensor is true when the object is not blocking the light beam.

signalsOutputs from photoelectric sensors are typically either digital or analog. Digital outputs are on or off and are usually three wire PNP (sourcing output) or NPN (sinking outputs). The exception to this is a relay output that provides a dry or isolated contact requiring voltage being applied to one pole.

Analog outputs provide a dynamic or continuous output that varies either a voltage (0-10 volt) or current (4-20mA) throughout the sensing range. Voltage outputs are easier to integrate into control systems and typically have more interface options. The downside to a voltage output is it should not be ran more than 50 feet. Current outputs can be ran very long lengths without worry of electrical noise. As additional advantage of the analog output is that it has built in diagnostics, at its minimum there will always be some current at the input unless the device completely fails or the wire is damaged.

Some specialty photoelectric sensors will provide a serial or network communication output for communications to higher level devices. Depending on the network, IO Link, for instance, additional diagnostics can be provided or even parameterization of the sensors. io-link
Interested in learning more about photoelectrics basics? Visit Balluff Basics library on our web site. You can also request a copy of the new Photoelectric Handbook.

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