IO-Link Simplifies Connectivity on Robotic End-Effectors

In my last two blogs, Rise of the Robots: IO-Link… and Realize Productivity Gains with Smart Robotic Tooling , I shared how implementing IO-Link and incorporating pneumatic and electric smart grippers can help maximize your use of robotics in your applications. In this blog, I will discuss how you can get more from your robots through expanded use of end-effectors in your applications.

As pneumatic air and vacuum systems have been an integral part of automation projects of the past, these systems can also benefit from gains in intelligence moving forward. Smart vacuum generators can provide feedback on the operation of the system; for example, if cups are starting to wear or fail, the smart devices can be used to provide estimates on remaining service life through predictive maintenance calculations. Key components like process sensors, variable regulators, pneumatic grippers, and pneumatic valve manifolds are available with IO-Link technology at a reasonable price. More importantly, these devices dramatically simplify integration, installation, and maintenance with built-in diagnostics and parameterization tools. By utilizing smart pneumatics, we substantially reduce wiring complexity in new installations and expedite downtime repairs.

Easier I/O and Connectivity on Robotic End-Effectors

Figure 1 – An industrial robot with IO-Link I/O hubs and valve manifold control on the EoAT.

However, most people avoid adding these types of smart technologies to end-effectors due to cable management issues or the effort to put high-flex Ethernet or many conductors into the robot dress pack. With IO-Link and its use of standard conductors for communication, integrators and machine builders have been able to install already available conductors in the arm or use lower-cost high-flex sensor cables to communicate with IO-Link smart devices on the end of arm tooling (EoAT).

Smart I/O hubs allow for standard sensors to be used with simplified wiring and on large tooling, valve manifolds can be mounted and controlled on the EoAT (Figure 1). If tool change is needed for the application, non-contact wireless connectivity can send power and signal across an airgap, increasing application capabilities and functionality.

Manufacturers big and small have gained impressive intelligence at the robot’s end-effector using IO-Link electric grippers, smart pneumatics and tooling enabled with IO-Link sensors. As you look to your next robotic automation project, consider how you could reduce integration efforts, improve part quality, enhance production flexibility, gain more process visibility, and increase application capabilities of EoAT. To realize all the benefits of an industrial robot system and earn productivity gains in machine tending, assembly and material handling applications, smart grippers, smart sensors, and smart tooling (enabled by IO-Link) are a necessary part of your next smart factory project.

How Lower-Priced Cables Can Cost More and Cause Downtime

Cable selection is an important step when it comes to creating a system to yield the most uptime. Sensors tell a machine when to start and stop or begin the next process. The time to replace and rewire the cable are costly, but small in comparison to the costs associated with the unplanned downtime a failed cable can cause. That is why it is so important to make sure you are selecting the right cable for the job.

There are three cable jacket materials that are the most commonly used: polyvinyl chloride (PVC), polyurethane (PUR), and thermoplastic elastomer (TPE). Each material has its own strengths and weaknesses, allowing them to work better in certain applications than others. When selecting cables, you must consider all factors and conditions such as the temperature rating, whether the cable will have contact with any chemicals, how much will the cable be moving, will it encounter weld spatter, vibrations, etc. Once you have this information you can start to look for what cable will work best for you.

Polyvinyl Chloride (PVC)
PVC is the most general cable jacket. It usually has the lowest price, it’s durable and offers a decent temperature range. This is the cable jacket you will see in most standard automation applications, but it isn’t built for harsher environment conditions. PVC does not perform well with weld spatter and can’t handle high heat; it also does not have the best chemical resistance compared to other cable material options.

Polyurethane (PUR)
The PUR jacket is a step up from PVC in most areas. It provides a higher abrasion resistance and better chemical resistance but has a lower temperature range. PUR jackets are mostly used in areas with lots of oils and chemicals or in a cable carrier due to its higher abrasion rating.

Thermoplastic Elastomer (TPE)
TPE jacketed cables deliver a higher temperature rating, are more flexible, offer great chemical resistance, and can resist weld spatter. These cables work in weld cells, high-heat applications, cable carriers, and much more. Because of the higher performance, TPE jacketed cables tend to have a higher price point than PVC and PUR but will last longer and can be used effectively in a variety of environments.

There are many other cable jacket options available that are more application specific than the three mentioned above. Cables with silicone or FEP jackets will have higher temperature ranges than even TPE and can more effectively resist weld spatter. Steel-jacketed cables provide great protection from abrasion and constant vehicle traffic or any falling objects that could cut through a standard jacket. There are also TPE-V cables that are made for the Food and Beverage industry that have all the necessary certifications and can undergo many washdown cycles.

A key to reducing downtime and MRO costs is selecting the right cable for the application. Choosing a lower-priced cable can costs your more in the long run. Using a PVC cable in a weld cell will cost you much more in replacements costs and downtime than would be spent on using a slightly more expensive silicone cable designed to last 4 times longer in that environment. Don’t be blinded by initial costs; instead, focus on the needs of your application and you will see the benefits.

Sensor and Device Connectivity Solutions For Collaborative Robots

Sensors and peripheral devices are a critical part of any robot system, including collaborative applications. A wide variety of sensors and devices are used on and around robots along with actuation and signaling devices. Integrating these and connecting them to the robot control system and network can present challenges due to multiple/long cables, slip rings, many terminations, high costs to connect, inflexible configurations and difficult troubleshooting. But device level protocols, such as IO-Link, provide simpler, cost-effective and “open” ways to connect these sensors to the control system.

Just as the human body requires eyes, ears, skin, nose and tongue to sense the environment around it so that action can be taken, a collaborative robot needs sensors to complete its programmed tasks. We’ve discussed the four modes of collaborative operation in previous blogs, detailing how each mode has special safety/sensing needs, but they have common needs to detect work material, fixtures, gripper position, force, quality and other aspects of the manufacturing process. This is where sensors come in.

Typical collaborative robot sensors include inductive, photoelectric, capacitive, vision, magnetic, safety and other types of sensors. These sensors help the robot detect the position, orientation, type of objects, and it’s own position, and move accurately and safely within its surroundings. Other devices around a robot include valves, RFID readers/writers, indicator lights, actuators, power supplies and more.

The table, below, considers the four collaborative modes and the use of different types of sensors in these modes:

Table 1.JPG

But how can users easily and cost-effectively connect this many sensors and devices to the robot control system? One solution is IO-Link. In the past, robot users would run cables from each sensor to the control system, resulting in long cable runs, wiring difficulties (cutting, stripping, terminating, labeling) and challenges with troubleshooting. IO-Link solves these issues through simple point-to-point wiring using off-the-shelf cables.

Table 2.png

Collaborative (and traditional) robot users face many challenges when connecting sensors and peripheral devices to their control systems. IO-Link addresses many of these issues and can offer significant benefits:

  • Reduced wiring through a single field network connection to hubs
  • Simple connectivity using off-the-shelf cables with plug connectors
  • Compatible will all major industrial Ethernet-based protocols
  • Easy tool change with Inductive Couplers
  • Advanced data/diagnostics
  • Parametarization of field devices
  • Faster/simpler troubleshooting
  • Support for implementation of IIoT/Industry 4.0 solutions

IO-Link: an excellent solution for simple, easy, fast and cost-effective device connection to collaborative robots.

Press Shops Boost Productivity with Non-Contact Connections

In press shops or stamping plants, downtime can easily cost thousands of dollars in productivity. This is especially true in the progressive stamping process where the cost of downtime is a lot higher as the entire automated stamping line is brought to a halt.

BIC presse detail 231013

Many strides have been made in modern stamping plants over the years to improve productivity and reduce the downtime. This has been led by implementing lean philosophies and adding error proofing systems to the processes. In-die-sensing is a great example, where a few inductive or photo-eye sensors are added to the die or mold to ensure parts are seated well and that the right die is in the right place and in the right press. In-die sensing almost eliminated common mistakes that caused die or mold damages or press damages by stamping on multiple parts or wrong parts.

In almost all of these cases, when the die or mold is replaced, the operator must connect the on-board sensors, typically with a multi-pin Harting connector or something similar to have the quick-connect ability. Unfortunately, often when the die or mold is pulled out of the press, operators forget to disconnect the connector. The shear force exerted by the movement of removing the die rips off the connector housing. This leads to an unplanned downtime and could take roughly 3-5 hours to get back to running the system.

 

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Another challenge with the multi-conductor connectors is that over time, due to repeated changeouts, the pins in the connectors may break causing intermittent false trips or wrong die identification. This can lead to serious damages to the system.

Both challenges can be solved with the use of a non-contact coupling solution. The non-contact coupling, also known as an inductive coupling solution, is where one side of the connectors called “Base” and the other side called “Remote” exchange power and signals across an air-gap. The technology has been around for a long time and has been applied in the industrial automation space for more than a decade, primarily in tool changing applications or indexing tables as a replacement for slip-rings. For more information on inductive coupling here are a few blogs (1) Inductive Coupling – Simple Concept for Complex Automation Part 1,  (2) Inductive Coupling – Simple Concept for Complex Automation Part 2

For press automation, the “Base” side can be affixed to the press and the “Remote” side can be mounted on a die or mold, in such a way that when the die is placed properly, the two sides of the coupler can be in the close proximity to each other (within 2-5mm). This solution can power the sensors in the die and can help transfer up to 12 signals. Or, with IO-Link based inductive coupling, more flexibility and smarts can be added to the die. We will discuss IO-Link based inductive coupling for press automation in an upcoming blog.

Some advantages of inductive coupling over the connectorized solution:

  • Since there are no pins or mechanical parts, inductive coupling is a practically maintenance-free solution
  • Additional LEDs on the couplers to indicate in-zone and power status help with quick troubleshooting, compared to figuring out which pins are bad or what is wrong with the sensors.
  • Inductive couplers are typically IP67 rated, so water ingress, dust, oil, or any other environmental factor does not affect the function of the couplers
  • Alignment of the couplers does not have to be perfect if the base and remote are in close proximity. If the press area experiences drastic changes in humidity or temperature, that would not affect the couplers.
  • There are multiple form factors to fit the need of the application.

In short, press automation can gain a productivity boost, by simply changing out the connectors to non-contact ones.

 

Ensure Optimum Performance In Hostile Welding Cell Environments

The image above demonstrates the severity of weld cell hostilities.

Roughly four sensing-related processes occur in a welding cell with regards to parts that are to be joined by MIG, TIG and resistance welding by specialized robotic /automated equipment:

  1. Nesting…usually, inductive proximity sensors with special Weld Field Resistance properties and hopefully, heavy duty mechanical properties (coatings to resist weld debris accumulation, hardened faces to resist parts loading impact and well-guarded cabling) are used to validate the presence of properly seated or “nested” metal components to ensure perfectly assembled products for end customers.
  2. Poke-Yoke Sensing (Feature Validation)…tabs, holes, flanges and other essential details are generally confirmed by photoelectric, inductive proximity or electromechanical sensing devices.
  3. Pneumatic and Hydraulic cylinder clamping indication is vital for proper positioning before the welding occurs. Improper clamping before welding can lead to finished goods that are out of tolerance and ultimately leads to scrap, a costly item in an already profit-tight, volume dependent business.
  4. Several MIB’s covered in weld debris

    Connectivity…all peripheral sensing devices mentioned above are ultimately wired back to the controls architecture of the welding apparatus, by means of junction boxes, passive MIB’s (multiport interface boxes) or bus networked systems. It is important to mention that all of these components and more (valve banks, manifolds, etc.) and must be protected to ensure optimum performance against the extremely hostile rigors of the weld process.

Magnetoresistive (MR), and Giant Magnetoresistive (GMR) sensing technologies provide some very positive attributes in welding cell environments in that they provide exceptionally accurate switching points, have form factors that adapt to all popular “C” slot, “T” slot, band mount, tie rod, trapezoid and cylindrical pneumatic cylinder body shapes regardless of manufacturer. One model family combines two separate sensing elements tied to a common connector, eliminating one wire back to the host control. One or two separate cylinders can be controlled from one set if only one sensor is required for position sensing.

Cylinder and sensor under attack.

Unlike reed switches that are very inexpensive (up front purchase price; these generally come from cylinder manufacturers attached to their products) but are prone to premature failure.  Hall Effect switches are solid state, yet generally have their own set of weaknesses such as a tendency to drift over time and are generally not short circuit protected or reverse polarity protected, something to consider when a performance-oriented cylinder sensing device is desired.  VERY GOOD MR and GMR cylinder position sensors are guaranteed for lifetime performance, something of significance as well when unparalleled performance is expected in high production welding operations.

But!!!!! Yes, there is indeed a caveat in that aluminum bodied cylinders (they must be aluminum in order for its piston-attached magnet must permit magnetic gauss to pass through the non-ferrous cylinder body in order to be detected by the sensor to recognize position) are prone to weld hostility as well. And connection wires on ALL of these devices are prone to welding hostilities such as weld spatter (especially MIG or Resistance welding), heat, over flex, cable cuts made by sharp metal components and impact from direct parts impact. Some inexpensive, effective, off-the-shelf protective silicone cable cover tubing, self-fusing Weld Repel Wrap and silicone sheet material cut to fit particular protective needs go far in protecting all of these components and guarantees positive sensor performance, machine up-time and significantly reduces nuisance maintenance issues.

To learn more about high durability solutions visit www.balluff.com.

Flexible Cables Don’t Flex For Long

Recently I read an article in Machine Design called “When Flexible Cables Doesn’t Flex for Long” by Leland Teschler which talks about different aspects of flexible cable terms, causes of breakage and testing.

The article touches on different lingo between flexible, high-flex and high-flex-life. Flexible and high-flex mean the same thing.  Google’s definition of flexible is the capability of bending easily without breaking. High-flex-life is described by Northwire as a cable designed to survive 10 million to 20 million flexing cycles. Those are just the common terms used to describe flexing of a cable, but there are manufacturers that use their own flexing name to describe their cables.

Teschler also describes the feel of a cable, whether the cable bends easily or not, based on different degrees of limpness or stiffness. “All in all, cable makers say the stiffness or limpness of the cable has nothing to do with its flex life.” The article goes on to describe a limp cable as a jacket that is made from soft materials, or finely stranded conductors, that allow the cable to move easily but is not meant to be used in applications with repeated flexing.

ULTestSetupThe last part of the article mentions how cables are tested for flexing. There is not a standard in the industry so different manufacturers can use differernt tests. The 3 most common tests are twist and flex test, tick-tock cable test, and UL test setup. Teschler pointed out the main focus for UL and CSA is to test for fire safety and UL test the cables for runs of 15,000 cycles.

Overall, I really enjoyed the article and highly suggest giving it a read to understand more about raw cable and testing requirements.

To see Balluff’s offering of UL listed cables click here.

Stop Industrial Network Failures With One Simple Change

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It’s the worst when a network goes down on a piece of equipment.  No diagnostics are available to help troubleshooting and all communication is dead.  The only way to find the problem is to physically and visually inspect the hardware on the network until you can find the culprit.  Many manufacturers have told me over the past few months about experiences they’ve had with down networks and how a simple cable or connector is to blame for hours of downtime.

2013-08-19_Balluff-IO-Link_Mexico_Manufactura-de-Autopartes_healywBy utilizing IO-Link, which has been discussed in these earlier blogs, and by changing the physical routing of the network hardware, you can now eliminate the loss of communication.  The expandable architecture of IO-Link allows the master to communicate over the industrial network and be mounted in a “worry-free” zone away from any hostile environments.  Then the IO-Link device is mounted in the hostile environment like a weld cell and it is exposed to the slag debris and damage.  If the IO-Link device fails due to damage, the network remains connected and the IO-Link master reports detailed diagnostics on the failure and which device to replace.  This can dramatically reduce the amount of time production is down.  In addition the IO-Link device utilizes a simple sensor cable for communication and can use protection devices designed for these types of cables.  The best part of this is that the network keeps communicating the whole time.

If you are interested in learning more about the benefits that IO-Link can provide to manufacturers visit www.balluff.us.

Back to the Basics on Receptacles

From The Free dictionary by Farlex, a receptacle is defined as “A fitting connected to a power supply and equipped to receive a plug.”  I like this definition it describes both halves of the receptacle.  In the automotive industry, the back half of a receptacle has threading on the nut with leads that could possibly connect a power supply.  The front half describes which kind of cordset is needed.  Typically, receptacles are used in a control cabinet, where there is easy access and out of the movement of machinery.  Inside a control cabinet is a power source and/or programmable logic controller (PLC) which a receptacle would be wired to in the configuration of the controller.  Receptacles used on a control box normally have a tight seal to keep out moisture and dust.

receptacle_1When looking at a receptacle there are two ends with different kinds of threading.  In the front of the receptacle has a connection for a cable to connect to the outside environment, cells, and machinery, to the control box. The different cables could have diameter widths of M8, M12, 7/8”, 1” and more. From the picture, we see the front side of the receptacle calls for the M12x1 which would use a M12 cable. The first number is always the diameter of the outer threads.  The other end of the receptacle, ½”-14NPT, where the leads come out, has another diameter referred as to the mounting type.  There are many different kinds of mounting: Metric, PG, NPT, front mount, back mount, panel mount, etc.  The two mounts types being explained here are Metric and NPT.

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Got a Question About Sensors or Connectivity? Ask the Experts!

Normally the sensor experts here at SensorTech blog chose topics that we think will interest our readers.  But this week we’re asking our readers to send us their top questions about sensors and connectivity.  Got a question about how sensors work?  How to select them?  How to hook them up to a network?  How to properly install and set them up?  Some nagging problem with an application that’s driving you crazy?  We’d like to hear from you!

Please enter your question (or questions) in the comment box below.  We’re looking forward to doing our best to help you out!

Distributed Modular I/O Demo on Demand!

Everyone likes things on demand right?  Movies, TV shows, chocolate, you name it.  My good friend, John Harmon, has prepared a YouTube video so that you have at your fingertips an on-demand presentation on Distributed Modular I/O.  It is a great overview of the available functionality of Distributed Modular I/O and what kinds of control products that are available utilizing this technology.  I realize the video is seven and a half minutes, which is pretty long for a web video, but I think he does an excellent job of keeping your attention and demonstrating the value of this technology.  Grab a soda and your favorite chocolate bar, put your phone on silent, and hit play on this excellent presentation.

Continue reading “Distributed Modular I/O Demo on Demand!”