Project Uptime – Pay Me Now or Pay Me Later

Back when I worked in the tier 1 automotive industry we were always trying to find time to break into our production schedule to perform preventative maintenance. The idea for this task was to work on the assembly machines or weld cells to improve sensor position, sensor and cable protection and of course clean the machines. As you all know this is easier said than done due to unplanned downtime or production schedule changes, for example. As hard as it is to find time for PM’s (preventative maintenance) it is a must to stay ahead and on top of production. PM’s will not only increase the production time, but it will also help maintain better quality parts by producing less scrap and machine downtime due damaged sensors or cables.

If you have read any of my previous posts you have probably noticed that I refer to the “pay me now or pay me later” analogy. This subject would fall directly into this category, you have to take the time to prevent machine crashes and damaged sensors and cables on the front side rather than being reactive and repairing them when they go down. It has been proven that a properly bunkered or protected proximity sensor will outlast the machine tooling when best practices are executed. It’s important to take the time and look at the way a sensor is mounted or protected or acknowledge when a cable is routed in harm’s way.

Click to enlarge

PM’s should be an important task that is part of a schedule and followed through in any factory automation or tier 1 production facility. In some cases I have seen where there is a complete bill of material (BOM) or list of tasks to accomplish during the PM time. This list will help maintenance personnel and engineering know what to look for and what are the hot spots that create unplanned downtime.  This list could also indicate some key sensors, mounting brackets and high durability cables that can improve the process.

For more information on a full solution supplier or products that can improve and decrease downtime click here.

Posted in All posts | Tagged , , , | Leave a comment

Level Sensing in Machine Tools

Certainly the main focus in machine tools is on metal cutting or metal forming processes.

To achieve optimum results in cutting processes coolants and lubricants are applied. In both metal cutting and metal forming processes hydraulic equipment is used (as hydraulics create high forces in compact designs). For coolant, lubricant and hydraulic tanks the usage of level sensors to monitor the tank level of these liquids is required.

Point Level Sensing

For point level sensing (switching output) in many cases capacitive sensors are used. These sensors detect the change of the relative electric permittivity (typically a change of factor 10 from gas to liquid). The capacitive sensors may be mounted at the outside of the tank wall if the tank material is non metallic like e.g. plastic or glass. The installation may even be in retrofit applications yet limited to non metallic tanks up to a certain wall thickness.

When using metal tanks the capacitive sensors enter the inner area of the tank via a thread and a sealing component. Common thread sizes are: M12x1, M18x1, M30x1,5, G 1/4″, NPT 1/4″ etc. For conductive liquids specially designed capacitive level sensors may be used which ignore build up at the sensing surface.

Continuous Level Sensing

Advanced process control uses continuous level sensing principles. The continuous sensor signals e.g. 0..10V, 4…20mA or increasingly IO-Link deliver more information to better control the liquid level, especially relevant in dynamic or precise applications.

When using floats the magnetostrictive sensing principle offers very high resolution of the level value. Tank heights vary from typically 200 mm up to several meters. Another advantage of this sensor principle is the high update rate (supporting fast closed loop systems for level sensing)

In many applications the  requirements for the level control solutions are not too demanding. In these cases the ultrasonic principle has gained significant market share within the last years. Ultrasonic sensors do not need a float, installation on the top of the tank is pretty easy, there are even sensor types available which may be used in pressurized tanks (typically up to 6 bar). As ultrasonic sensors quite often are used in special applications, field tests during the design in process are recommended.

Finally hydrostatic pressure transducers are an option for level sensing when using non pressurized tanks (typically  connected to ambient pressure through a bore in the upper area of the tank). With the sensor mounted at the bottom of the tank the level is indirectly measured through the pressure of the liquid column above the sensor (e.g. 10m of water level resembles 1 bar).

Summary

Concerning level sensing in metalworking applications in the first step it should be decided whether point level sensing is sufficient or continuous level sensing is required. Having chosen continuous level sensing there are several sensor principles available (selection depending on the application needs and features of the liquids and tank properties). It is always a good engineering practice to prove the preselected sensing concept with field tests.

To learn more visit www.balluff.com

Posted in All posts, Level Sensing, Liquid Level Sensing | Tagged , , , , , , , , , | Leave a comment

An Easy Solution to Extend Sensor Life

Quick-change prox mounts for proximity sensors.

Everyone is looking for quick tricks of the trade. Sensor failure can prove to be costly in any environment. One of the easiest ways to avoid unnecessary downtime would be to add a mounting bracket plus prox mount to the machine to extend the life of a sensor.

What is a prox mount?

It has a quick release tube mounted into a tubular bracket to change out a sensor easily. The sensor is assembled into the prox mount tube and locked into place with a compression ring and metal nut. The prox mount and sensor assembly is then mounted and adjusted as with any tubular sensor, but the prox mount will remain in place on future sensor replacement tasks.

Mounting accessories are geared toward extending sensor performance in harsh industrial conditions involving chemical attack, debris accumulation, shock/vibration/impact, and high temperatures. The brackets act as protection, as well as mounting for the sensor to extend the life of the sensor. Adding a prox mount to it add another layer of protection as well as reducing down time due to the quick release to change a sensor.

Fully Assembled Prox Mount with Sensor Installed

Mounting brackets are a simple solution to decrease installation costs by screwing in the bracket on the machine. They are also prolonging sensor life expectancy by giving it an added layer of protection. Add in the prox mount for a faster option to reduce unplanned downtime with the quick release of the sensors. This helps increase the overall performance and utility of sensors.

To get started visit www.balluff.us

Posted in All posts, Sensor Accessories | Tagged , , , , , | Leave a comment

What does that “Ready for IIoT” tag really mean?

These days almost every smart industrial device that comes to the market is advertised as “ready for IIoT.” But what does it actually mean? Before we get too technical, we should look at what the objectives are for IIoT and why it is important to the industrial age of our time.

In a previous post, “The promise of the Industrial Internet of Things (IIoT)“, we highlighted features such as Virtual IP address, to help address several things that plant maintenance and management would like to achieve. This blog touches those topics in a different perspective.

The concept of the Industrial Internet of Things (IIoT), or Industry 4.0, applies to the future of industrial automation, and these concepts heavily rely on the interoperability of a wide variety of devices and systems that communicate large amounts of data. This data is important because IIoT promises superior efficiency of machines and personalized manufacturing. Personalized manufacturing – also known as micro batch production or lot size one – means connecting with the customers at an individual level rather than connecting to masses. If efficiency and customization in production are the end goals or prime objectives for IIoT, these questions must be answered: What type of data would be necessary? Where and how is that data obtainable? In other words, what are the capabilities or characteristics of the device or system that really qualify as being “ready for IIoT”? Does simply providing an Ethernet connection to the device or adding a webserver qualify the device for IIoT? The answer is NO!

In my opinion, the following 5 key characteristics/capabilities, depending of course on the end user’s objectives, would qualify for being “ready for IIoT” tag.

If an end-user of automation wants to run the plant efficiently, the device or system should be able to provide information regarding; (1) Condition Monitoring, and (2) Automatic Parameterization

  1. Condition Monitoring enables predictive maintenance and eliminates unplanned downtime. Is the PLC or automation controller the right place for determining predictive maintenance? Maybe not. The PLC should focus on making sure the system is running effectively. Adding more non-application related stuff to the PLC may disrupt what is truly important. In most cases you would need a different PC or server to do this pattern analysis throughout the plant. A system or device with the “ready for IIoT” tag should be able to collect and provide that information to a higher level controls system/server. An example would be a power supply with IO-Link. Through the IO-Link master it tells the system about the stress or ambient temperature and predicts its lifetime.
  2. Automatic configuration or parameterization of sensors and systems. This feature enables plug-n-play benefit so that replacing devices is easy and the system automatically configures the replaced device to reduce downtime.

As IT and Controls Engineering work closer together, there are other characteristics of the devices that become important.

  1. Configurability of sensors and production line beyond controller of the system: Automation controllers in use today have physical limits of memory and logic. Today manufacturers are running multiple batches of different products on the same line which means more change over and more downtime. If the devices could allow for quick line change configurations such as set point changes for your sensors, different pressures on fluids, different color detections for the parts or even the ability to provide you with detection of the physical format change, that would significantly reduce your changeover times. In a PLC or controller, you can only build logic for factors known today (for ex. the number of configurations), but in the near future there will be additional product configurations. To be truly ready for the IIoT, you need devices that can be configured (with proper authorizations) in multiple ways. A webserver might be one of the ways – but that also has its limitations. Simple Network Management Protocol (SNMP) is widely used with several of the network management software tools in the IT world. OPC UA is another open communication protocol in industrial space. JSON is a protocol for cloud interface among many others. A device that can offer connectivity, via SNMP, OPC UA, JSON or other such open formats, to connect to other network software tools to gather information or configuration would solve several of these challenges without burdening the existing PLC or controller logic. In other words, these types of interfaces can connect your machine directly to an MRP or similar enterprise-level system which would make production floors much more efficient for quick changeovers.
  2. Capability for asset tracking, and quick troubleshooting: These features become important when there are hundreds of parameters changing and configurations evolving as your system becomes smarter and more efficient. To ensure right things are happening down the line, error-proofing your system becomes essential, and this involves additional information tracking. So the systems or solutions you choose should have these features.
  3. Scalability for the future: This characteristic can be interpreted in many different ways. But, in this blog it refers to adding features and functions as the need arises and building in capability to adapt to these changes is needed so that you are not starting from scratch again when the business needs to evolve again.

So, as we move into this new era of manufacturing, it is important to understand what the “ready for IIoT” tag on the device you are investing in means, and how it is helping you become more efficient or helping you connect to your customer one-on-one. Using IIoT to implement an ‘Enable and Scale’ plan would be the best way to meet the ever-evolving needs for the plant floor.

To learn more about IIoT and Industry 4.0 visit www.balluff.us.

Posted in All posts, Industrial Internet of Things | Tagged , , , , , , , , | 1 Comment

Real-Time Optical Thickness Gauging for Hot Rolling Mills

An ever-present challenge in hot rolling operations is to ensure that the material being produced conforms to required dimensional specifications. Rather than contact-based measurement, it is preferred to measure the material optically from a standoff position.

Light band gauging station in hot strip rolling operation detects material thickness in real time.

Light band gauging station in hot strip rolling operation detects material thickness in real time.

In some instances, this has been accomplished using two ganged analog optical lasers, each detecting opposite sides of the material being measured. Through mathematical subtraction, the difference representing thickness could be determined. One difficulty of the approach is the need to put a sensor both above and below the material under inspection.  The sensor mounted below could be subjected to falling dirt and debris. Further, only a single point on the surface could be measured.

A new approach uses a scanning laser to create a band of light that is used to directly measure the thickness of the material.  An analog or digital IO-Link signal represents the measured thickness to a resolution of 0.01mm with a repeat accuracy between 10μm to 40μm depending on distance between emitter and receiver.  What’s more, the measurement can be taken even on red-hot metals. The illustration above shows a flat slab but the concept works equally well or better on products with a round profile.

To learn more visit www.balluff.us

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

A new angle on rotary feedback

steelindustryTransporting hot materials (ex. steel slabs) from one location to another via a walking-beam is common place in steel manufacturing. In the past, rotary encoders have typically been used to provide the precise feedback of rotary movement for these types of applications. However, optical encoders are prone to failure in harsh environments. Steel mills utilizing walking-beams for material handling have plenty of dirt and particulates in the air as well as produce high shock and vibration. All of these would contribute to an overall harsh environment which would shorten the life of an optical encoder.

Precise position checking and the continuous adjustment of rotational movements are extremely important on the walking-beam. Inclination Sensors are ideally suited for these exact tasks. With contact-free angle measurement, they guarantee maximum precision when the slabs are being transported. Inclination Sensors do not need mechanical coupling in contrast to rotary encoders, are compact and robust, and measure the deviation from the horizontal on an axis of up to 360°.
inclination-axisDowntime at a Steel Mill can cost up to tens of thousands of dollars per hour. The next time you need you have an angular measurement application in such harsh environments, you may want to consider an Inclination Sensor. It will surely be up to the task!

For more information on Balluff solutions for the metallurgy industry, start here.

For more information, visit www.balluff.com.

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

IO-Link Hydraulic Cylinder Position Feedback

Ready for a better mousetrap?  Read on…..btl_io-link

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

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

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

Connectivity

First and foremost, the story of IO-Link is that it offers easy, simple connection of sensors and IO to nearly any industrial network.  You can read more about that here.

Simplicity

Another big advantage of IO-Link is the ability to connect sensors to the network using standard, simple, unshielded M12 connectors and cables.  Compared to analog systems, which require shielded cabling, and sometimes unusual or proprietary connectors, connecting IO-Link sensors to the network is simpler, and usually less costly.

Visibility

Unlike their traditional analog counterparts, position sensors with IO-Link offer built-in diagnostic capabilities.  Sensor status can be monitored over the network, greatly simplifying troubleshooting and fault detection.

Flexibility

This is where IO-Link position sensors really start to shine.  Traditional analog position sensors provide one thing: position feedback in the form of an analog signal (obviously).  IO-Link position sensors provide position feedback, of course…but wait, there’s more.  In addition to position feedback, IO-Link sensors can provide velocity/speed information, temperature, and differential position (the difference between two position magnets).  And the best part?  All of this functionality can be freely configured over the network.  Plus, sensor configurations can be stored and subsequently downloaded to a replacement sensor if necessary.

Suitability

It’s worthwhile to point out that IO-Link linear position sensors are ideal for most positioning or position monitoring applications.  Just as with analog sensors though, they’re probably not suitable for high-performance closed-loop servohydraulic motion control applications.  In those applications, interfaces that are capable of providing super-fast, deterministic data, such Synchronous Serial Interface (SSI) or even Ethernet/IP are more suitable.

To learn more visit www.balluff.us

You can also learn more in this overview flyer.

Posted in IO-Link, Linear Position and Distance Measurement | Tagged , , , , | 1 Comment

Basic Color Sensor Overview

PrintIn the past, color sensors emitted light using red, green and blue LEDs’. The sensors were then able to distinguish colors using the RGB components of the reflected light back to the sensor’s receiver. As technology has progressed true color sensors have been developed that not only can compare colors but measure them more accurately than the human eye.

Color sensors are based on diffuse technology and can be compared to a fixed focus or convergent sensor because of the focused light spot. Unlike color contrast sensors that only detect the difference between two colors based on brightness, color sensors can detect a wide range of colors.

cielabTrue color sensors typically use white LED’s which allow for a greater color spectrum evaluation. Combine this with the CIELAB color system which is one of the most versatile color systems and the result is a color sensor that equals or exceeds the human eye. The CIELAB color system is a three-dimensional independent infinite representation of colors. The L component for lightness and a and b components for color are predefined absolute values. Lightness varies from black (0) to the brightest white (100). Color channel a varies from green negative 100 to red positive 100. Color channel b varies from blue negative 100 to yellow positive 100 with gray values at a=0 and b=0.

Due to the technology, color sensors can check only a small spot of color but can check this spot amazingly fast – up to 1.5 kHz in case of the Balluff’s fiber optic BFS 33M which also has a range of 400mm. Unlike a color sensor camera, which will focus on the object’s surface pattern and may cause false readings the true color sensor will ignore patterns thus providing more accurate color detection. In addition the true color sensor will have more outputs than the color camera.

Smart color cameras are working with RGB but could work also with HSV color models. They could be used to check larger areas for the same color or color codes on a part, but have slower update rate of 50 Hz. Special cameras for faster applications are available in the market but at higher costs. It is important that the light source for the smart color cameras be a white light with a standardized white balance, and that this light must kept constant for all checks to avoid errors.

The sophistication on the front end of the color sensor can be much more advanced and still remain a cost effective option for industrial use due to the fact that a camera requires a much larger processing system. The more sophisticated the sensors are in the camera the more robust the processor must be in order to process or map the data into an image.

To learn more visit www.balluff.us.

You can also request a digital copy of our Photoelectric Handbook here.

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

Put Out the Fire

Every time I enter tier 1 and tier 2 suppliers, there seems to be a common theme of extreme sensor and cable abuse. It is not uncommon to see a box or bin of damaged sensors along with connection cables that have extreme burn-through due to extreme heat usually generated by weld spatter. This abuse is going to happen and is unavoidable in most cases.  The only option to combat these hostile environments is to select the correct components, such as bunker blocks, protective mounts, and high temperature cable materials that can withstand hot welding applications.

Example of bad bunkering. Sensor face not protected. Plastic brackets and standard cables used.

Example of bad bunkering. Sensor face not protected. Plastic brackets and standard cables used.

In many cases I have seen standard sensors and cables installed in a weld cell with essentially zero protection of the sensor. This results in a very non-productive application that simply cannot meet production demands due to excessive downtime. At the root of this downtime you will typically find sensor and cable failure. These problems can only go on for so long before a culture change must happen throughout a manufacturing or production plant as there is too much overtime resulting in added cost and less efficiency. I call this the “pay me now or pay me later” analogy.

Below are some simple yet effective ways to improve sensor and cable life:

Example of properly bunkered sensors with bunker block and silicone wrapped cable

Example of properly bunkered sensors with bunker block and silicone wrapped cable

  • Apply flush sensors vs. non-flush sensor in fixtures
  • Bunker the flush sensors to protect the face of the sensor (Let the bunker block take the spatter)
  • Apply sensors with special coatings to combat weld spatter
  • Apply sensors with steel faces for added insurance against contact damage
  • Apply high temp cables such as full silicone high durability offerings
  • Protect cables with silicone tubing and high temperature weld jackets
  • Wrap cables with weld repel tape to insure spatter will not penetrate the ends of the cable

If these simple steps are followed, uptime and efficiency will result in increased productivity with immediate improvements and positive results.

For information on welding improvements visit our website at www.balluff.us.

Posted in All posts, Cables and Connectors, Inductive Proximity Sensors, Object Detection Sensors, Sensor Accessories | Tagged , , , , , , , , | Leave a comment

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 new 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.

smartlightmodesThe 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.

Use Case #1: Stack Light Mode for Operation Status – The number of segments can be programmatically changed from 1 to the max segment number provided by the light (up to 5 in a five-segment SmartLight). Colors can be changed to red, blue, green, orange, yellow, white, or any other color of choice. This is the most traditional application of the SmartLight.

Use Case #2: Format Change Indicator – Many of our customers use the level mode to provide feedback to the operators when they are making adjustments to the machine. For example: red might indicate that the machine is out of alignment, yellow might mean the machine is getting closer to the specified alignment, and green might mean the machine is in the zone of alignment. Using the SmartLight in this fashion helped our customers save time in product changeovers because the operators didn’t have to come out of the cell to view the alignment status on a small HMI.  When the alignment of the machine is complete, the SmartLight can be programmed to switch back to the status indication mode or whatever mode of operation desired.

smartlightgifcroppedUse Case #3: Run Light Mode for Maintenance Indication – In this mode there are two colors – one color for the background and another color for the running segment. Along the assembly line where there are multiple work cells continuously processing raw materials in lock-step operation, downtimes are extremely costly. The standard status indicator will only indicate a problem at the work cell when the system stops, but it will not indicate a lack of raw material, for example. The moment the stack light turns red, the operator or the maintenance person is rushed to the site to first figure out what’s wrong before solving the problem. In Run Light mode, the SmartLight can be programmed to indicate different colors for the running segment and the background to show that attention is required at the cell. For example, as long as the running segment is running the machine is operational, but the background color can be changed to indicate raw material shortage, the need for mechanical adjustment of the machine, or the need for some electrical maintenance. Using a SmartLight, whoever is rushing the cell has a very good idea of what is required of them to get the system back up and running.

There are several more applications we want to share. Before we do that, we want to hear from you! Do you have a unique application for the SmartLight? Share your story with us here.

You can also learn more by visiting our website at www.balluff.us.

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