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…..”

4

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>>

3

#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>>

Posted in All posts, Industrial Identification, Industrial Networking, Level Sensing, Linear Position and Distance Measurement, Object Detection Sensors | Tagged , , , , , , , | Leave a comment

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.

BIP(1)_46630_Produktnews_korrBIP(2)_55370_00_P_00_00_00

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 www.balluff.com.

Posted in All posts, Analog Position Sensors, Linear Position and Distance Measurement | Tagged , , , , , , , , , | Leave a comment

Where Did You Find That Sensor?

I recently visited a customer that has a large amount of assembly lines where they have several machine builders manufacturing assembly process lines to their specification. This assembly plant has three different business units and unfortunately, they do not communicate very well with each other. Digging deeper into their error proofing solutions, we found an enormous amount of sensors and cables that could perform the same function, however they mandated different part numbers. This situation was making it very difficult for maintenance employees and machine operators to select the best sensor for the application at hand due to redundancy with their sensor inventory.

The customer had four different types of M08 Inductive Proximity sensors that all had the same operating specifications with different mechanical specifications. For example, one sensor had a 2mm shorter housing than one of the others in inventory. These 2mm would hardly have an effect when installed into an application 99% of the time. The customer also had other business units using NPN output polarity VS PNP polarity making it even more difficult to select the correct sensor and in some situations adding even more downtime when the employee tried to replace an NPN sensor where a PNP offering was needed. As we all know, the NPN sensor looks identical to the PNP offering just by looking at it. One would have to really understand the part number breakdown when selecting the sensor, and when a machine is down this sometimes can be overlooked. This is why it is so important to standardize on sensor selection when possible. This will result in more organized inventory by reducing part numbers, reducing efforts from purchasing and more importantly offering less confusion for the maintenance personel that keep production running.

Below are five examples of M08 Inductive sensors that all have the same operating specifications. You will notice the difference in housing lengths and connection types. You can see that there can be some confusion when selecting the best one for a broad range of application areas. For example, the housing lengths are just a few millimeters different. You can clearly see that one or two of these offerings could be installed into 99% of the application areas where M08 sensors are needed for machine or part position or simply error proofing a process.

Shawn1Shawn2.pngShawn3Shawn4                                                             Shawn5

For more information on standardizing your sensor selection visit www.balluff.com

 

Posted in All posts, Inductive Proximity Sensors, Object Detection Sensors | Tagged , , , | Leave a comment

Passive RFID Still the Way To Go For Work In Process (WIP)

With the rapid evolution of manufacturing technology it’s pretty tough to keep up with the latest and greatest products designed to help automate the manufacturing process. The big “buzz” surrounding RFID about a decade or so ago was Wal-Mart declaring that their top one hundred vendors would be required to tag every single item with an RFID tag. Well, that never came to fruition. Around the same time there was a lot of talk about active RFID systems as a new technology for work in process. Well, that didn’t ever quite materialize either.

While the active systems certainly have made an impact on yard and container management applications, passive RFID still rules the roost in WIP. In essence, the main difference between passive and active RFID is active tags require a battery which helps tagsto yield a much larger read range. One can imagine the benefits of an extremely long read range in a shipping yard, but on a production line the engineers are just fine with mounting the read head within a few inches of the work pieces. Eighty to ninety percent of the new WIP applications that we deal with still require High Frequency (HF) technology.   The other ten to twenty percent are using Ultra-High Frequency (UHF) which is still passive technology, just a longer read range. This is usually the case where the actual item being built is very large and it is very difficult to place a HF reader within inches of the work piece.

Ultimately, using active RFID for work in process is similar to using a sledge hammer to put a nail in a wall. It is simply overkill. So, while automation technology is on a course of change, it is clear that some of the “old faithful” equipment is still adequately addressing the needs on the production line.

To learn more about active vs. passive RFID tags, click here.

Posted in All posts, Industrial Identification, Industrial RFID Systems | Tagged , , , , , | Leave a comment

Boost Size-Change Efficiency with IO-Link Magnetic Encoders and Visualization

In many industries, especially in Packaging, the need to minimize capital equipment costs drives engineers to implement low-cost, manual methods of size change (also called format change) on their machinery. In most cases, this means hand-driven cranks with mechanical dial pointers and/or mechanical revolution counters.

While cost is saved on the procurement side, cost is also shifted over to the operational side. Plant management is left with the task of keeping accurate records of various machine set-ups needed to run different products, as well as the task of training machine operators to perform all machine set-ups correctly. It doesn’t always go as smoothly as expected, and machine reformatting can result in longer downtime than planned, machine stoppages, and possibly excessive scrap.

The key to size-change improvement is capturing the linear movements of the machine components and bringing them into the control system, and then providing “smart” visual feedback to the machine operator during setup. For capturing machine position, a robust and cost-effective magnetic linear encoder is ideal. However, traditional linear encoders deliver an A-B quadrature incremental signal, which requires re-homing upon start-up or after a power loss. What’s needed is an absolute encoder signal, but that brings other challenges such as the cost and complexity of implementing an absolute signal like SSI (Synchronous Serial Interface).

Fortunately, there’s a new encoder interface BML SL1 Absolute Magnetic Encoder with IO-Linkoption that eliminates the problem of non-absolute feedback and the hassle of absolute position signal interface: IO-Link. IO-Link is a multi-vendor, non-proprietary, device-level serial digital interface that can be aggregated onto today’s Ethernet industrial networks. Magnetic linear encoders are now available that feature absolute position indication combined with the ease and convenience of the IO-Link communication protocol.

Now we just need to provide visual feedback to the machine operator regarding which direction and how far to turn the hand cranks. Once smartlight_18x18_300dpiagain, IO-Link provides the answer in the form of an IO-Link-enabled, fully programmable multi-segment LED stack light. When a new machine set up is required, the position parameters are stored in the controller. The controller communicates over IO-Link to the LED stack lights, indicating to the operator which dials need to be turned and in which direction. For example, a horizontally mounted stack light could be lit red on the right half, indicating that the dial needs to be turned to the right. As the position moves closer to the proper setting, the red segments count down until the entire stack light goes green, indicating that the correct position for that axis has been reached. No paper records to maintain and store, and very little training required with the intuitive operator visualization.

For more information about IO-Link linear encoders click here, and to learn more about IO-Link programmable LED stack lights visit www.balluff.com.

Posted in All posts, Industrial Networking, IO-Link | Tagged , , , , | Leave a comment

Imagine the Perfect Photoelectric Sensor

Photoelectric sensors have been around for a long time and have made huge advancements in technology since the 1970’s.  We have gone from incandescent bulbs to modulated LED’s in red light, infrared and laser outputs.  Today we have multiple sensing modes like through-beam, diffuse, background suppression, retroreflective, luminescence, distance measuring and the list goes on and on.  The outputs of the sensors have made leaps from relays to PNP, NPN, PNP/NPN, analog, push/pull, triac, to having timers and counters and now they can communicate on networks.

The ability of the sensor to communicate on a network such as IO-Link is now enabling sensors to be smarter and provide more and more information.  The information provided can tell us the health of the sensor, for example, whether it needs re-alignment to provide us better diagnostics information to make troubleshooting faster thus reducing downtimes.  In addition, we can now distribute I/O over longer distances and configure just the right amount of IO in the required space on the machine reducing installation time.

IO-Link networks enable quick error free replacement of sensors that have failed or have been damaged.  If a sensor fails, the network has the ability to download the operating parameters to the sensor without the need of a programming device.

With all of these advancements in sensor technology why do we still have different sensors for each sensing mode?  Why can’t we have one sensor with one part number that would be completely configurable?

BOS21M_Infographic_112917

Just think of the possibilities of a single part number that could be configured for any of the basic sensing modes of through-beam, retroreflective, background suppression and diffuse. To be able to go from 30 or more part numbers to one part would save OEM’s end users a tremendous amount of money in spares. To be able to change the sensing mode on the fly and download the required parameters for a changing process or format change.  Even the ability to teach the sensing switch points on the fly, change the hysteresis, have variable counter and time delays.  Just imagine the ability to get more advanced diagnostics like stress level (I would like that myself), lifetime, operating hours, LED power and so much more.

Obviously we could not have one sensor part number with all of the different light sources but to have a sensor with a light source that could be completely configurable would be phenomenal.  Just think of the applications.  Just think outside the box.  Just imagine the possibilities.  Let us know what your thoughts are.

To learn more about photoelectric sensors, visit www.balluff.com.

Posted in All posts, Object Detection Sensors, Photoelectric Sensors | Tagged , , , , , , , , , , , , , | Leave a comment

How to Simplify Wiring in Process-Related Applications

If you have ever been on a process or power plant during commissioning or in case of a fault, you have probably asked yourself how to simplify wiring in process-related applications. In these industrial segments, engineers often encounter complex structures and are confronted with long signal paths. Individual subsystems, equipped with local programmable logic controllers (PLCs) or remote terminal units (RTUs), are usually connected via bus systems to the control room and SCADA system, whereby diagnostic tools are available for this network.

The fun starts with troubleshooting on the subsystem level. The individual sensors and actuators are still very often wired with copper in the traditional manner. This means that there are thick cable bundles in cable ducts, and the individual conductors at the cable ends must be terminated correctly and securely. Special care must be taken with analog signals, as a missing or incorrectly connected shield can also cause signal or measurement errors. Troubleshooting under these conditions can be very nerve-wracking (if all eyes are on you) and expensive (production or power downtime).

There are some markets where there are both strong automotive and process industries. Engineers who change sides are bringing alternative field wiring approaches, such as ASi and IO-Link with them. Since these technicians are familiar with the advantages of commissioning and troubleshooting in the production line, they have no reservations about implementation. So let’s take a look at the other side:

In the past in factory automation, parallel image11wiring has been used.

As product life-cycles are getting shorter and availability has to be high, there is a greater need for modular systems.

Therefore on the sensor/actor level, they are implementing IO-Link  more and more, which some people already call the USB port of automation systems. Some advantages of IO-Link include:

  • Flexibility in connecting to a wide variety of devices through the same M12 connector. The unshielded cable and robust digital signal effectively conquer issues such as line interference and overcome flexing or bending restrictionsimage22
  • Digitized analog values (from 4-20 mA, 0-10 V, PT100/1000, thermocouple Type J/K) instead of analog signals
  • Additional diagnostic information directly from hubs and sensors/actuators
  • Possibility to adapt the host bus system to other countries or customer demands. Only the master module has to be exchanged (most of the wiring diagram will stay the same)

This interesting technical report by Andritz Hydro (Austria) shows how IO-Link was successfully implemented in a hydro power project: Powering Africa! (more information about IO-Link solutions).

Posted in All posts, Industrial Networking, IO-Link | Tagged , , , , , , , , , , | Leave a comment

Measurement Fundamentals: Position Measurement vs. Distance Measurement

Continuous measurements on industrial machines or the materials that these machines are making, moving, or processing can be categorized into two main types of sensors:  position measurement sensors, and distance measurement sensors.  It’s a somewhat subtle distinction, but one that is important when evaluating the best measurement sensor for a particular application.

Position Measurement: When we speak in terms of position measurement, we’re typically talking about applications where a the sensor is installed onto a machine, and mechanically coupled to the moving part of the machine – or is installed into a hydraulic cylinder that is moving the machine – and is reporting the continuous position of the machine.  In a positioning application, the questions that need to be answered are: “Where is it?  Where is it now?  And now?”.

Scott image1

Examples of position measurement sensors include magnetostrictive linear position sensors and magnetically encoded linear sensors.  With each of these sensor types, either the sensor itself, or the position marker, is typically attached to the moving part of the machine.

Distance Measurement: Distance measurement sensors, on the other hand, are used in applications that require accurate measurement of a target that is typically no part of the machine.  A good example would be an application where parts or components are moving along a conveyer belt, and the position of those parts needs to be accurately measured.  In this example, it wouldn’t be practical, or even possible, to attach a sensor to the moving part.  So its position needs to be measured from a DISTANCE.  In a distance measuring application, the question being answered is: “How far away is it?”.

Scott image2

Examples of distance measuring sensors include photoelectric (laser) sensors and inductive distance sensors.  These types of sensors are usually mounted on the machine, or in the immediate vicinity of the machine, and are aimed at a point or a path where the object to be measured is, or will be, located.

In summary, while both position and distance sensors do much the same thing – provide continuous indication of position – the applications for each are generally quite different.  Gaining an understanding of the application and its requirements will help to determine which type of sensor is the best choice for the task.

For more information on position and distance measurement sensors, visit www.balluff.com.

Posted in All posts, Linear Position and Distance Measurement | Tagged , , , , , | Leave a comment

In-Cylinder Position Sensing in Electrically Conductive Hydraulic Fluids

The standard for hydraulic fluid in the industry is mineral oil, which is a dielectric medium that does not conduct electricity. Yet environmental concerns have led to the search for alternatives that are less harmful in case of leaks and spills. One development is biodegradable oils, typically with biological origins, often called “bio-oils” for short. They behave in many ways like mineral oil with a key difference in that they can be electrically conductive.

Another alternative hydraulic fluid is water-glycol mixtures, commonly known as the anti-freeze found in your liquid-cooled automobile engine. Water-glycol solutions are used for several reasons, including environmental concerns but more often conditions of extreme heat or extreme cold. They have much lower viscosity than oil, and there are several fluid power application considerations as a result, but water-glycol mixtures, like bio-oils, are electrically conductive.

Image2

So, when it comes to cylinder position sensing, why should we care whether or not the hydraulic fluid is electrically conductive? Well, because it could come back to bite us if we put an incompatible position sensing technology into a cylinder that is filled with a conductive fluid.

I recently met an engineer who’d run into this exact situation. A hydraulic cylinder was ordered from the manufacturer with an “integrated position feedback sensor.” The feedback sensor turned out to be a resistive potentiometric type, in other words, a linear potentiometer or “pot.” The entire length of the resistive material is “wetted” inside the cylinder, along with the traveling “wiper” that moves with the piston. In typical applications with non-conductive, mineral-based hydraulic fluid, this works fine (although linear pots do tend to be somewhat fragile and do wear out over time). However, when the resistive material and wiper is wetted in a conductive liquid, all kinds of wrong start happening. The signal becomes very erratic, unstable, and lacks resolution and repeatability. This is because the fluid is basically short-circuiting the operation of the open-element linear potentiometer.

This caused quite a headache for the engineer’s customer and subsequently for the engineer. Fortunately, a replacement cylinder was ordered, this time with a non-contact magnetostrictive linear position sensor. The magnetostrictive sensor is supplied with a pressure-rated, protective stainless steel tube that isolates the electrical sensing element from the hydraulic medium. The position marker is a magnet instead of a wiper, which the sensor can detect through the walls of the stainless steel pressure tube. So, a magnetostrictive sensor is absolutely unaffected by the electrical properties of the hydraulic medium.

A magnetostrictive linear position sensor carries a lot of performance and application advantages over linear pots that make them a superior technology in most applications, but when it comes to conductive hydraulic fluids they are definitely the preferred choice.

To learn more about linear position sensors visit www.balluff.com.

Posted in All posts, Linear Position and Distance Measurement | Tagged , , , , , | Leave a comment

Who Has Access to Your Machine Controls?

If you can provide a list of people who have authorized access to your machine controls, then you are ahead of the game. If you can truly ensure that only the people on that list are accessing the machine and not sharing their credentials, then you are way ahead of the game.

Limiting access to the controls of a machine is certainly not a new concept. I see many organizations still using a mechanical key system for override or start up.  According to multiple controls engineers, the main issue with that is people share, copy, and misplace these keys on a regular basis. In this case, just about everyone on the plant floor would have access to the controls of any machine.

appl_packaging_primary-packaging_Ensure-access-control

Just about all of us carry a device that allows us to enter and exit our buildings. Whether it be a badge or a key fob, the technology is the same. RFID adds accountability to machine access control.  For example: Jane, the team lead, has full authority to make changes in the control system. The production line comes to a screeching halt and needs to be restarted. In order to restart the machine, Jane has to present her RFID badge to a reader near the controls and she is then given access to make some adjustments within the machine. When Jane authenticates into the machine, the date, time, and Jane’s ID can be recorded. This adds full accountability to the controls and deters Jane from giving John her badge to let him restart the machine.  If John makes unauthorized changes he makes them in Jane’s name.

Access control has become a popular solution in the last few years as machines have become more critical to operation.  Like most RFID applications there are multiple ways to address this.  The key is to select a vendor who has a core competency in the industrial space with knowledge of industrial control systems.

To learn more about how RFID technology controls machine access click here or visit www.balluff.com.

Posted in All posts, Industrial Identification, Industrial RFID Systems | Tagged , , | 1 Comment