Solar tracking systems and sensors

Over the last few years there has been a lot of discussion on how we will meet the global energy demand in the future. And what will be the technologies to generate it? In the end it all comes down to the levelized cost of electricity (LCOE), which is the sum of all costs of a power plant divided by the total electricity that is generated over the plant’s lifetime. All companies in the renewable energy industry focus on reaching lower LCOE compared to conventional power generation (especially gas). Their biggest advantage is that there are no costs for fuel (sun light, wind, water).

solarpanelsLet’s take solar power as an example. Principally there are two ways to use the sun light: First it can be converted directly to electricity (photovoltaics). Second, it can be used indirectly by generating thermal energy (concentrated solar power). In order to reach higher efficiency solar trackers are used to orient photovoltaic panels, reflectors, or mirror towards the sun. On the other hand they add costs to the system. Therefore it must be carefully calculated whether a tracker (single or dual axis) is required or not (fixed installation).

solarpanels2Single axis trackers are used to position photovoltaic panels, parabolic troughs or linear Fresnel collectors from east to west on a north to south orientation. Depending on the required tracking accuracy different sensors are used for this task. As most of the photovoltaic trackers use electric linear actuators, very often inductive sensors are installed on the actuator for position feedback. They are cost optimized and are a standard feature in the actuators. Another option is to use inclination sensors that are directly mounted on the rotating shaft to provide angle feedback (e.g. in linear Fresnel plants). As inclinometers are mounted on the moving part, there is cable wear that could lead to failure over time. For high end tracking, as is required in parabolic trough plants, magnetic tape systems are used as rotary encoders. A magnetic tape is mounted around the shaft and a sensor head is installed on the frame of the tracker. The sensor counts the pulses accurately and provides continuous position feedback without any wear.

solarpanels3Dual axis trackers are used to position concentrated photovoltaic (CPV) panels, parabolic reflectors (dish) or mirrors (heliostats). Especially in central receiver plants high accuracy is required. They need high temperatures and therefore have to focus lots of light on a central receiver on top of a tower in the middle of the heliostat field. As there is an azimuth and an elevation axis, two position feedback systems are required. The elevation angle could be solved with an inclinometer, but this does not work for the azimuth position.  Again, the position could be measured with embedded rotary encoders directly on the drive. But there is again backlash, and accuracy is of highest importance as heliostats could be one mile away from the central receiver. Magnetically coded position and angle measurement systems can be mounted on both axis (azimuth and elevation) and provide direct position feedback with highest accuracy.

More information can be found in this brochure about power generation. http://asset.balluff.com/std.lang.all/pdf/binary/861522_162563_1305_en-US.pdf

Special thank you to Bernd Schneider, Industry Manger – Balluff GmbH for contributing to this post.

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JSON Objects and How They Can Streamline an IIoT Application

In web development, JSON objects are a programmer’s dream come true. JSON, or JavaScript Object Notation, is much similar to XML (EXtensible Markup Language) in that it’s used as a standard format to organize and transfer data across multiple programming languages. For example, say you want to send sensor data from a SQL database to a JavaScript front end. JavaScript doesn’t know SQL syntax and SQL doesn’t know JavaScript syntax. How do these different languages communicate? JSON/XML will act as a middle ground between the two allowing them to talk to each other. When given a choice between the two, I’m always going to pick JSON objects as they are much more efficient than XML. They are shorter in length and easier for computers and people to interpret. Here’s what 3 sensors would look like in XML versus JSON:

xml

Example of XML

json

Example of JSON

dpropHow does this apply to the Industrial Internet of Things? The JSON format for data transfer is so universal that IO-Link modules host it on a web server. This server is accessible by entering the IP address of the module. The module data can be seen in JSON format by modifying the IP address and adding “/dprop.jsn” into the URL of a web browser (i.e. 192.168.0.1/dprop.jsn). You should see something similar to the image on the right.

reqqresarchThe “dprop” stands for data propagation or simply the movement of data from one source to multiple sources. This data is delivered with a standard request-response system. Say you’re writing some software that uses the sensor data as variables. All that’s needed to get that sensor data is a few lines of code that send a request to the module which in turn responds with your data.

opcuaHow does this differ from the Industrial Internet of Things (IIoT) application frameworks from my past blogs? Previously, we discussed using OPC UA software to subscribe to PLC data and forwarding this data to a SQL database. From there, the application would query SQL for the data and render it appropriately for the user experience. Using JSON objects, we entirely eliminate the need for SQL or OPC UA software by accessing the data directly from the module. This not only makes the application independent from the PLC but also uses much less network traffic. However, using JSON objects, we can only subscribe to data from IO Link devices.

All acronyms aside, there are a million different ways to structure an IIoT application. The best fitting architecture depends on the environment. Systems with standard input/output will most likely need some form of communication with the controller. IO-Link systems will streamline this process by allowing the user to directly access the module’s IO Link data. How you go about building your application is entirely up to you. In the end, however, having this information readily available via the Industrial Internet of Things will be more beneficial than you could have ever imagined.

To learn more about IIoT visit www.balluff.us.

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Demand the Best from Your RFID Partner

RFIDThat seems like a no-brainer statement, but often I find myself talking to customers who are frustrated with their current vendor for a myriad of reasons. An RFID project can require a pretty decent chunk of capital investment so when something doesn’t go as planned people start looking for answers immediately. This usually presents a great opportunity for us to go in and save the day, but it’s hard for me to ignore the time, money and resources that were wasted. Having witnessed this on several occasions I have concluded that there are a large number of RFID companies who are niche suppliers, but there are very few who can qualify as an RFID Partner. The RFID partner helps ensure success from idea to implementation to future expansion. That said, here is a list of things to consider prior to discussing your application with an RFID company:

  • Does the partner offer hardware that communicates over USB, Serial, TCP/IP, Ethernet/IP, Profinet/Profibus, CC-Link, Ethercat, etc?
  • Does the partner offer a wide range of form factors of readers, tags, and antennae?
  • Does the partner build hardware for multiple frequencies?
  • Is the partner willing to build custom equipment just right for your application?
  • Does the partner offer support before, during and after the project?
  • Does the partner have a core competency in the application?
  • Can the partner meet application specs such as, high temperatures, high speed reading on the fly, storing and reading large amounts of data, high ingress protection rating, etc.?
  • Does the partner develop and design products which are scalable and easily expandable?

If you can answer yes to all of these questions then chances are you are pretty well set. With such a mature technology there are many ways for RFID companies to set themselves apart from one another. However, there are only a few who are willing to do what it takes to be considered a partner.

To learn more about RFID technology visit www.balluff.us/rfid

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Linear Measurement Sensors for Short Stroke Applications

We’ve posted numerous articles here on the Sensortech blog about linear position sensors used for applications such as hydraulic cylinder position feedback, plastic injection molding machinery, tire manufacturing machinery, etc.  What all of the applications have in common is that we’re generally talking about fairly long linear travels, usually longer than 12″, sometimes up to 300″.spindle

But in applications such as spindle clamp positioning on machine tools or positioning of
linear movements on automated assembly machinery, travels are sometimes only a couple of inches, and the available space to mount a position sensor is extremely limited.  Fortunately, there are highly capable linear position sensors that are perfectly suited for such applications.

For example, there are sensors that use an array of inductive coils to detect the bips
precise linear position of a simple metal target.  These sensors, with working strokes ranging from < 1″ up to around 5″ have are extremely compact, with very little dead zone.  That means they fit into very tight spaces, where other type of linear position sensors simply couldn’t.

Typically, these types of sensors provide a position signal in the form of an analog voltage (0-10V) or current (4-20 mA).  Increasingly though, IO-Link interfaces are gaining in popularity, offering simplified wiring, better noise immunity, built-in diagnostics, and the ability to easily get the position data into virtually any industrial field-bus architecture.

For more information, visit www.balluff.com

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5 Common IIoT Mistakes and How to Avoid Them

IIoT is the perfect solution for all your data accessibility needs, right? If you check out my previous blogs, I discussed the many benefits of using the Industrial Internet of Things (IIoT) to remotely access data. However, if not used properly, IIoT can get you into some trouble. Let’s review 5 common mistakes to avoid when building your IIoT application.

1. Excluding your IT department
It’s crucial to make sure your Information Technology group is involved in this project. IIoT applications can be very taxing on your network. It’s easy to forget some key aspects like bandwidth and network traffic when developing your application. But when your application is finished, your IT department is going to want to know what network resources that are being used. Some questions they might ask include:

  • How many potential clients will the server have at any given time?
  • What is the max refresh rate of your application?
  • How frequent do you query the SQL server?
  • How are your queries structured?
  • What might be some vulnerabilities on this application?
  • What measures are you taking to protect these vulnerabilities?

It’s going to be a lot easier if they are included right away so everyone has a good understanding of what resources are available and how to protect them.

2. Excluding OT and Controls Engineers
Similar to the IT department, it’s important to include the controls engineer especially if you plan on hosting data from a PLC. The controls engineer is going to want to determine what data is publicly available and what data should be kept private. Some questions the controls engineer(s) might ask include:

  • What is your application trying to show?
  • What PLC data do you want to use for this?
  • Is your application going to write data to the PLC?
  • Do any modifications need to be made to the PLC code?

Keep in mind that any modifications that need to be made to the PLC will probably have to go through the controls engineer. This is to ensure that no code changes on the PLC will impact the efficiency and safety of production.

3. Running out of date software
Software that you write and the software that your application relies on should always be up to date. In other words, if you use a module or library in your code, it’s important to make sure you have the most up to date version. Also, it’s important to keep updating your application for additional security and functionality. Out of date software can lead to potential application crashes or even vulnerabilities for cyber attacks. Keep in mind, an application that runs on out of date software makes the server host vulnerable as well as its clients.

IIoT_Pyramid4. Unorganized data flow
Data flow is an important concept to consider early on in the development of your application. Say you have a server forwarding PLC data to a SQL database that is then utilized in a web application. The web application acts as a historian and analyzes data change over time. Is it better to calculate the data in the back-end application, the SQL database, the server forwarding the data or the PLC? The answer depends on the situation but typically, it’s best to keep the data calculations as close to the source as possible. For example, say your back-end application calculates percentages based on yesterday’s production compared to today’s. In this situation, if the back-end application crashes, you lose historian calculations. Typically, a SQL database is much more reliable as far as downtime and crashes and it will run whether your back-end application is functional or not. Therefore, it would be better to do these calculations in the SQL database rather than the back-end script. Continuing this concept, what if the PLC could do this calculation? Now the forwarding server, the SQL database, and the back-end script can all crash and you would still have your historian data for when they go back up. For this reason, the closer to the source of data you get, the more reliable your calculations based on that data will be.

5. Unprotected sensitive data
Possibly one of the most important things to remember when developing your application. Even simple applications that just display PLC data can give a hacker enough for an attack. Think about this IoT scenario: Say I have a server that hosts data from my personal home such as whether or not my front door is locked. This information is important to me if I want to check if someone forgot to lock the front door. But to a burglar, this data is just as useful if not more as he/she can now check the status of my door without having to leave their car. If I don’t protect this data, I am openly advertising to the world when my front door is unlocked. This is why encryption is crucial for sensitive data. This is also why it’s important to discuss you project with the controls engineer. Data that seems harmless might actually be detrimental to host publicly.

Data accessibility is evolving from a convenience to a necessity. Everyone’s in a hurry to get their data into the cloud but keeping these ideas in mind early on in the application development process will save everyone a headache later on. That way, IIoT really can be the perfect solution for all you data accessibility needs.

To learn more about IIoT visit www.balluff.us.

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Level Detection Basics – Part 2

In the first blog on level detection we discussed containers and single point and continuous level sensing.  In this edition we will discuss invasive and non-invasive sensing methods and which sensing technologies apply to each version.  Keep in mind that when we are talking about level detection the media can be a liquid, semi-solid or solid with each presenting their own challenges.

tankInvasive or direct level sensing involves the sensing device being in direct contact to the media being sensed.  This means that the container walls or any piping must be violated leading to issue number one – leakage.  In some industries such as semiconductor and medical the sensing device cannot contact the media due to the possibility of contamination.

level_btl-sf-wThe direct mounting method could simplify sensor selection and setup since the sensor only has to sense the medium or target material properties.  Nonetheless, this approach imposes certain drawbacks, such as costs for mounting and sealing the sensor as well as the need to consider the material compatibility between the sensor and the medium.  Corrosive acids, for example, might require a more expensive exotic housing material.level_bsp_w

Invasive sensing technologies that would solve level sensing applications include capacitive, linear transducers, hydrostatic with pressure sensors.

In many cases the preferred approach is indirectly or non-invasively mounting the sensor on the outside of the container.  This sensing method requires the sensor to “see” through the container walls or by looking down at the media from above the container through an opening in the top of the container.  The advantages for this approach are easier mounting, lower cost and easier to field retro-fit.  The container wall does not have to be penetrated, which leaves the level sensor flexible and interchangeable in the application.  Avoiding direct contact with the target material also reduces the chances of product contamination, leaks, and other sources of risk to personnel and the environment.

level_bglIn some cases a sight glass is used which is mounted in the wall of the tank and as the liquid media rises it flows into the sight glass.  When using a sight glass a fork style photoelectric sensor can be used or a capacitive sensor can be strapped to the sight glass.

The media also has relevance in the sensor selection process.  Medical and semiconductor applications involve mostly water-based reagents, process fluids, acids, as well as different bodily fluids.  Fortunately, high conductivity levels and therefore high relative dielectric constants are common characteristics among all these liquids.  This is why the primary advantages of capacitive sensors lie in non-invasive liquid level detection, namely by creating a large measurement delta between the low dielectric container and the target material with high dielectric properties.  At the same time, highly conductivity liquids could impose a threat to the application.  This is because smaller physical amounts of material have a larger impact on the capacitive sensor with increasing conductivity values, increasing the risk of false triggering on foam or adherence to the inside or outside wall.

Non-invasive or indirect level sensing technologies include photoelectrics, capacitive, linear transducers with a sight glass and ultrasonics.

For more information visit www.balluff.com.

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Why everyone in manufacturing should host a Manufacturing Day Event

tourAs we wrap up our second annual manufacturing day event at Balluff (Oct 7th 2016), I am motivated to see so many kids and adults excited about manufacturing. This is an amazing industry to be a part of and as the 4th industrial revolution is upon us, we must inspire the next generation to see the light.

At Balluff’s MFGDAY event, we offered hourly time slots for attendees. During that hour, they received a plant tour and participated in hands-on labs. The tour focused on lean manufacturing work-cells, automated systems, and lot-size-one flexible manufacturing. Visitors learned how these tools are utilized at a US manufacturer to be competitive in a global market, how manufacturing technologies are utilized and how STEM education is applied in a manufacturing environment.

labThe hands-on labs were by far the favorite part for most attendees. We offered 5 hands-on labs from a speed game of flexible manufacturing to technology discovery experience about infrared light. Each lab taught the students and parents about how different sensor technologies worked and created a positive effect on the manufacturing process.

vanOutside the labs, interactive automation games were available to play and win prizes. The automated bags game was a hit with adults and kids and our RFID tag catapult game took quite a lot of skill. Everything was designed to inspire interest in manufacturing automation and help educate both adults and aspiring students to consider careers in advanced manufacturing.

Our motivation at Balluff to participate in MFGDAY is three-fold:

  • Bridge the US Manufacturing Skills Gap. Help our manufacturing community bridge the 600k+skills gap by building interest in the public for a career in manufacturing.
  • Connect with our community. We want to be involved in our community, improve outcomes for local students and support the local economy. That’s why we partnered with local schools like Gateway Community College and Cincinnati State to turn a budding interest into a solid path.
  • Motivate our employees. Talking about how awesome manufacturing is is fun. And seeing the excitement of a little kid when they can see infrared light through a cellphone camera was the highlight of many employees’ day.

As attendees left the event we asked them a few questions to gauge their interests and the effect of the day on their attitudes toward manufacturing. I am happy to report that we increased an interest in manufacturing careers by 22% in both kids and adults. Many people walked away with a better understanding of how STEM education can positively affect manufacturing careers and 90% agreed that factory automation is cool. Check out our new infographic on MFGDAY16 at Balluff and our press release has event more details.

mfgday-infographic_101216

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Three Common Mistakes When Selecting a Sensor

Balluff Globalprox inductive proximity sensorsIn a previous post we addressed things to consider when selecting a sensor. Inductive sensors are solid performers when the correct options are selected. However, the best option to accommodate a given application condition are often overlooked. Here are three common mistakes I’ve seen time and time again:

  1. Choosing Flush instead of Non-Flush mounting specifications – or vice versa
    A flush offering can be embedded into a metal bracket or mounting block without false triggering and output. A Non-Flush offering will need a free zone at the sensing face so the sensor does not false trigger from the metal in the mounting block itself.
  2. Selecting an Inductive Sensor that is not the best choice for detecting your material
    For example if the target is aluminum selecting an all metal sensor (Factor 1) offering would be the best choice since there is no reduction in the sensing range on the non-ferrous material.
  3. Selecting a sensor that is not fit for your application conditions
    If the sensor is applied in a hostile application such as welding then a sensor with special coatings is required to combat the weld spatter that is present in this type of application.

The number of options available can be overwhelming but selecting the right sensor for your application can lead to reduced downtime by preventing sensor failure. You can learn more about Inductive Proximity Sensor technologies by visiting balluff.us/inductive.

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Harsh Industrial Environments Challenge Plant Operators

Most industrial processes do not take place in a climate-controlled laboratory or clean room environment. Real-world industrial activity generates or takes place under harsh conditions that can damage or shorten the life expectancy of equipment, especially electronic sensors.

A cross-section of industrial users was surveyed about operating conditions in their facilities. The responses revealed that plant operators are challenged by a variety of difficult environmental factors, the biggest being heat, dust/dirt/water contamination, vibration, and extreme temperature swings.

linearpositionsensorinfographic

Over one-third of the industrial users surveyed reported that premature sensor failure is a problem in their operations. That is a surprisingly high percentage and something that needs to be addressed to restore lost productivity and maintain long-term competitiveness.

Many heavy industries are dependent on automated hydraulic cylinders to move and control large loads precisely. The cylinder position sensors are often subjected to damaging environmental conditions that shorten their life expectancy, leading to premature failure.

Fortunately, there are measures that can be taken to reduce or eliminate the occurrence of sensor-related downtime. Help is available in the form of a free white paper from Balluff called “Improving the Reliability of Hydraulic Cylinder Position Sensors”.

To learn more about this topic you can also visit www.balluff.us/micropulse.

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IMTS 2016 Review: IO-Link Enables Industry 4.0 Installations

We have been talking about IO-Link for a long time.  The benefits to manufacturers like “hot-swapping” a smart device.  One of the benefits for machine builder is reducing commissioning time.  So it was not surprising to me to find IO-Link on the exhibit floor at IMTS 2016, but it was surprising how much IO-Link was used on equipment and demonstrations.

Makino IO-Link I/O Hubs

On a cool demo of robotic load and unload of two machining centers from the team at Makino Machine IO-Link was used for I/O applications driving solenoids and collecting sensor inputs.

What is neat about I/O hubs regardless of the brand is the ability to collect many simple discrete sensor inputs and drive outputs over one IO-Link channel.  It can save tim dramatically over traditional hardwired applications.

Beckhoff IO-Link Master for EtherCAT

Beckhoff IO-Link Master for EtherCAT

Molex IO-Link Inter-operability

At Beckhoff they were showing their IO-Link master options for a slice in the PLC.

Molex displayed their Profinet IO-Link master and slave devices like analog converter and digital I/O hubs.  What I liked about their demo is they showed how open and easy the IO-Link technology is to integrate other company’s devices like the Balluff SmartLight.

Klingelnberg IO-Link

In the Klingelnberg booth on one of their flagship machines IO-Link masters and SmartLight were installed on the machine. IO-Link inductive positioning Smart Sensors from Balluff were used for measurement of the chucking position.

And inter-operability was also shown with multiple manufacturer’s process sensors with IO-Link installed tied back to a Profinet master.  Since IO-Link is an open standard with over 90 automation vendors, it was nice to see the inter-operability in action.

Caron Eng Demo of SmartLight

The SmartLight was shown all over the IMTS show due to Caron Engineering’s easy integration into a PC without an industrial network.  Too many booths to name had the SmartLight integrated with the Caron IO-Link Master solution.

The fact that IO-Link can be used with multiple master interfaces and options, really makes it an easy to select and universal choice for a variety of applications.

 

I look forward to seeing what unfolds in the two years before the next IMTS show.  I anticipate there will be a dramatic and continued adoption of IO-Link as it enables and scales Industry 4.0 and IIoT applications.

To see more or join the conversation check out #IMTS2016 on Twitter.

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