IO-Link Safety: What It Is and Isn’t

Comparing “IO-Link” and “Safety” to “IO-Link Safety”

There are many I/O blocks that have “IO-Link” and “Safety” in their descriptions, which can cause some confusion about which safety features they include. Here’s an overview of different safety-named blocks and how they compare to IO-Link Safety.

Safety Network Blocks

These blocks have I/O ports that use Pin 4 and Pin 2 as OSSD signals (safety ports). OSSD—output switching signal devices—send 24-volt signals over two wires to confirm that a device is operating in a safe condition. If 0 volts are detected in either signal, besides their safety-checking 0-volt pulses, it’s read as a safety event that signals the machine to go into a safe state. Safety network blocks are only for standard (non-network) safety devices. These blocks communicate directly back to a Safety Controller over safety protocols like CIP Safety, PROFIsafe, etc. These blocks typically can monitor between 8-16 standard safety devices. There is no intelligence built into the safety devices.

Safety Network Blocks with IO-Link

Blocks in this category usually have a mixture of I/O ports on them. The ports can range from standard I/O to standard IO-Link communication, and in addition, include ports that use Pin 4 and Pin 2 as OSSD signals (safety ports). These blocks communicate over the safety protocols with only a few ports to connect standard (non-network) safety devices. There is some versatility with these blocks since you can wire standard sensors, IO-Link devices, and safety devices to it. The drawback is, you will always run short of the port style you need and, in the end, use more blocks to cover either the safety or IO-Link needs of the application. There is no intelligence built into the safety devices.

Safety over IO-Link Blocks

In this system/architecture, there are standard IO-Link Masters communicating to the Safety PLCs/Controllers over standard protocols like EtherNet/IP, PROFINET, etc. Connected to the IO-Link Ports of these Masters are Safety over IO-Link devices, currently limited to only Safety over IO-Link hubs. The Safety PLCs/Controllers communicate via safety protocols like PROFIsafe to the standard IO-Link Master, and then using the IO-Link communication channel, they bridge the gap to the Safety over the IO-Link hub via the “black channel.” These Safety over IO-Link hub’s ports use Pin 4 and Pin 2 as OSSD signals (safety ports), so standard (non-network) safety devices can be connected. This system provided a “gap filler” while IO-Link Safety was being developed. In this system/architecture, the standard IO-Link Masters allowed standard IO-Link devices and Safety over IO-Link hubs to be connected to any ports. This brought even more versatility to an application and the beginnings of the benefits of IO-Link. Still, there is no intelligence built into the safety devices.

IO-Link Safety

IO-Link Safety adds a safety communication layer to IO-Link. The difference between this and Safety over IO-Link is that this safety layer applies to both the IO-Link Master and IO-Link Safety devices. Within a CIP Safety or PROFIsafe network, the safety communication protocol has top priority over standard EtherNet/IP or PRIFONET data if both are existing on the same physical network. The same is true for IO-Link Safety: both standard and safety IO-Link protocols can exist on the same physical cable between the IO-Link Master ports and IO-Link Safety devices, with IO-Link Safety carrying the top priority. For a deep dive into the IO-Link Safety protocol, I suggest visiting the IO-Link Consortium’s website at io-link.com. In this system/architecture, you have IO-Link Safety Masters, which communicate to the Safety PLCs/Controllers over safety protocols like CIP Safety, PROFIsafe, etc. The ports on the Masters can utilize Pin 4 and Pin 2 as OSSD signals (safety ports), so standard (non-network) safety devices can be connected. Pin 4 can also be used to carry standard IO-Link and IO-Link Safety communication to standard IO-Link devices and IO-Link Safety devices, respectively. This allows for the most versatile safety solution in the market–IO-Link Safety Masters that can accept standard (non-network) safety devices, standard IO-Link devices, and IO-Link Safety devices. Intelligence in the IO-Link Safety devices is now available.

Benefits of IO-Link Safety

    • IO-Link Safety devices are fieldbus neutral: you just need to specify the IO-Link Safety Master to match the Safety PLCs/Controllers protocol.
    • IO-Link Safety Master port versatility: standard (non-network) safety devices, standard IO-Link devices, and IO-Link Safety devices can be connected.
    • Parameter storage: standard IO-Link and IO-Link Safety device’s parameters can be stored for ease of device replacement.
    • Smart IO-Link Safety device data: more data available, like internal temperature, humidity, number of cycles, power consumption, diagnostics, etc.
    • Simplified wiring: IO-Link Safety devices are still connected to the IO-Link Master port with a standard 3 to 4 conductor cable.
    • IIoT fit: IO-Link Safety gives more visibility to upper-level systems like SCADA, allowing safety device-level monitoring.

I am looking forward to seeing how quickly IO-Link Safety will be accepted, with how IO-Link numbers have skyrocketed over the last few years. The future looks great for IO-Link with IO-Link Safety, IO-Link Wireless and in the future, Single-Pair Ethernet (SPE). With all these new capabilities, what application can’t IO-Link support?

Reduce the Number of Ethernet Nodes on Your Network Using IO-Link

Manufacturers have been using industrial Ethernet protocols as their controls network since the early 1990s. Industrial Ethernet protocols such as Ethernet/IP, ProfiNet, and Modbus TCP were preferred over fieldbus protocols because they offered the benefits of higher bandwidth, open connectivity and standardization, all while using the same Ethernet hardware as the office IT network. Being standard Ethernet also allows you to remotely monitor individual Ethernet devices over the network for diagnostics and alarms, delivering greater visibility of the manufacturing data.

With Ethernet as the key technology for Industry 4.0 and digitalization, more and more devices will have Ethernet capabilities. Typical industrial Ethernet nodes on a plant floor could include PLC controllers, robots, I/O devices for sensors, actuators, flowmeters, transducers and manifolds. While, it’s great getting all the data and diagnostics of the entire manufacturing process, having every device connected via Ethernet has some downfalls. It can lead to larger Ethernet networks, which can mean more costs in hardware such as routers, switches and Ethernet cables, and some Ethernet software license costs are based on the number of Ethernet nodes being used in the network.

Also, as more Ethernet devices are added to a network, the Ethernet network itself can get more complex. Each individual Ethernet device requires an IP address. If an Ethernet node stopped working and needed to be replaced, an operator would need to know the previous IP address of the device and have quick access to the manual with instructions on how to assign the previous IP address to the new device. Someone must also manage the IP addresses on the network. There will need to be a list of the IP addresses on the network as well as the available ones, so when a new Ethernet device is added to the network, a duplicate address is not use

One way to reduce the number of Ethernet nodes while still getting device data and diagnostics is by using IO-Link for field device communications. IO-Link is an open point-to-point communication standard for sensors and actuators published by IEC (International Electrotechnical Commission) as IEC 61131-9. Since it’s fieldbus and manufacturer independent, there is a long list of manufacturer devices that come with IO-Link. Each IO-Link device can then be brought back to a single Ethernet node, through an IO-Link to Ethernet gateway. Since it’s open technology, there are also multiple manufacturers that make different IO-Link to industrial Ethernet gateways.

On the IO-Link to Ethernet gateway, each channel has an IO-Link master chipset. It is designed to automatically communicate and provide data as soon as an IO-Link device is connected to a port. So, there is no addressing or additional setup required. IO-Link is point to point, so it’s always a single IO-Link device connected to a single port on the gateway using a standard sensor cable. Depending on the number of IO-Link devices to be connected to a single Ethernet node, IO-Link gateways can come in 4, 8 or 16 device channels. This graphic (image 1) shows six IO-Link devices connected to a single 8-channel Ethernet gateway. This gateway then communicates back to the Ethernet PLC controller as a single IP address with a standard Ethernet cable. Without using IO-Link, this might require all six devices to be industrial Ethernet devices. Each device would have its own IP address to set up, along with six Ethernet cables going back to a 6-port managed switch before going to the PLC controller.

 

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Image 1: Six IO-Link devices connected to a single 8-channel Ethernet gateway.

IO-Link Devices Connected:

  1. Device I/O Hub used to connect to 16 standard discrete sensors/photoeyes.
  2. Valve Manifold used to control up to 24 coils.
  3. Visual Indicator Light
  4. RFID Processor System
  5. Pressure Sensor
  6. IO-Link to Standard Analog (0-10V or 4-20ma) Converter

Why Train on Industrial Ethernet?

trainingAn industrial Ethernet network is vastly different from an office Ethernet network in several key ways, and the key to optimizing your industrial network in light of these differences, is hands-on training.

First of all, the environment in industrial applications can degrade the actual cable itself. Some cable manufacturers actually rate their cables’ ability to withstand these environmental factors. They use the acronym MICE, and rate the cable as appropriate for one of three environments: M1I1C1E1 for office environments, M2I2C2E2 for light industrial environments, and M3I3C3E3 for industrial environments. The letters actually stand for: Mechanical factors such as shock and vibration, Ingress from moisture, Climatic factors such as temperature and sunlight, and Electromagnetic interference such as noise caused by inductive loads, welders, variable frequency drives, etc. Other cable vendors observe the recommendations of ODVA and offer cables that are ODVA compliant.

Secondly, industrial Ethernet networks can have a high amount of multicast traffic. In the early years of Ethernet hubs were used to link devices. The problem is that information coming into one port of a hub was redirected to all of the other ports on the hub. With the advent of switches, unicast traffic was now directed to only the port for the intended recipient device. This is true for both managed and unmanaged switches: they both handle unicast traffic well. The problem for the unmanaged switch comes when you encounter multicast traffic. Since an unmanaged switch does not employ IGMP Snooping (Internet Group Management Protocol), the switch does not know what to do with multicast traffic. It starts acting like the old hubs: it directs all multicast traffic to all ports. With a managed switch and with IGMP Snooping turned on, the switch knows exactly where to send this multicast traffic and directs it only to the intended recipients. Multicast traffic can be anything from produced tags to input modules configured for multicast. These can be very common in industrial applications using PLCs.

Thirdly, we now have tools available in many switches and routers to prioritize the traffic on an Ethernet network. This becomes especially important when you have high-speed applications, motion applications, or time synchronization applications. In the past all Ethernet data was equal. The feedback coming from a servo drive had to wait just as long as a person trying to get online with a PLC. Now many automation vendors are marking their data with priority codes. Allen-Bradley marks their data in layer three with DSCP markings, and Siemens uses layer two markings with PCP marks, for instance (a VLAN tagging mechanism). In either case, if your switch or your routers are not configured properly to recognize and use these priority codes, you are not taking advantage of the QoS feature that could help get your important data through first (Quality of Service).

Only through proper training can you learn not only what the key issues are but also how to properly deploy your hardware to fully optimize your network. Balluff offers hands-on training with actual automation equipment, switches, and routers to help you do just that. You can learn more about the courses Balluff has to offer at www.balluff.us.

1 Visual Way to Improve Operator Performace

Many manufacturers I talk to are excited about the possibilities that our new Smart Light technology, used in level mode, brings to their production or machines.  Here’s a video if you havent seen it yet:

It works over virtually any industrial network with an open standard called IO-Link, which I’ve discussed many times in previous posts.

What I’m really impressed with is the number of people integrating the level mode as a quick and easy way to give instantaneous feedback to an operator on their performance to a quota or as a count-down timer.  Here you can see in the middle of the right photo a bright green bar light just to the left of the red kanban rack.  There are multiple of these lights in this image.

Tesla Motors Blog – Factory Upgrade

This light is a five zone Smart Light operating in level mode.  As the cycle time winds down, the light decreases in value until there is no more time, at that point it flashes bright red to notify the operator to cycle to the next vehicle.  It keeps the production on track and helps operators know quickly and easily how much time remains.  What I’ve been told is nice about this is how bright the light is and that it is easily install-able without a controls cabinet or slice i/o j-box like you can see in the photo.  Others like it because it makes the data visual from all over, where HMIs require you to stand right in front of them for information.

So if you are trying to think about ways to visualize data in your process or production to operators or managers, there are many others out there already using Smart Light for that application. Check it out.

Rise of the Robots – 3 Ways to Be On Their Team

While originally a mixed reviewed 1994 console video game, the recently published report by The Boston Consulting Group titled “The Rise of Robotics”  really made me realize how important it is that we embrace robotics in our manufacturing processes.  And I strongly agree with this statement: “Because robots can sharply improve productivity and offset regional differences in labor costs and availability, they’ll likely have a major impact on the competitiveness of companies and countries alike.”  They studied the growth of the usage of robots in personal, commercial, military and industrial use and the numbers were quite powerful.  Of interest to me is the rise in industrial robotics; doubling in 5 years from $5.8b to $11.0b in 2015.  And the growth is expected to more than double again by 2025 to $24.4b in the industrial space.

What this means for manufacturers, machine builders and component suppliers is we need to make sure our people are trained to support this growth and that we we have strong peripheral technologies to support robots as they grow and expand.  Even today there are some great technologies available in sensors and controls that make robotic integration easier for manufacturing companies.

So here are the three ways to make sure you are your robot’s ally.

  1. Maximize Their Payload!

    No one wants to be treated like they can’t help… especially your robots, they want you to utilize them and feel appreciated.  For most robotics right now, payload size & payload weight is a limiting factor.  Mini sensing products with precision switch points, small form factors and low mass allow for the design of low weight, compact payloads without limiting the functionality or speed of the robot.

  2. Keep them Working!

    A working robot is a happy robot.  By adding flexible tooling or quick-change tooling to the end-effector of a robot you can have one arm perform multiple functions and keep idle arms to a minimum, increasing their value and “happiness.”  Multiple products are out there to allow for this, however there is a technology that allows for sensor connections through inductive coupling that dramatically decreases repair issues and downtime due to tool changer pins.

  3. Remove the Chains!  

    What’s the deal with cable dress packs… they look like really bad suspenders sometimes… you see them, you don’t like how they look, but you need it to keep your pants on… I guarantee that robots don’t like these things either… And with all that flexing something in there will fail regularly.  There are some great technologies to reduce the sensor cables running on the arm and add flexibility and they are supported by the open standard IO-Link (discussed in other posts here!).

So as you integrate robots more and more into the manufacturing we are doing, please start thinking how to align yourself as a robot’s ally.  Because I know I want to be on this guy’s team…

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.

Light it Up! Industrial Stack Lights are old news…

I am seriously excited about the new Smart Light.  It will revolutionize how we automate and interface with people working in the manufacturing environment.  If you didnt watch this video… you need to watch this video.

Even if you don’t know what a stack light is, you will want one of these for your discotec to light it up!

Operating on the open communication protocol IO-Link that I have discussed in previous posts, I think this single part number will improve the factory for:

  • an operator wanting to know when to refill a feederbowl, position a part, or empty a full output bin
  • a maintenance guy needing to know what cell is causing the machine downtime
  • a plant manager wanting to know the machine output, speed, productivity

If you want more information on how this works visit the Smart Light webpage.

The Spring Line is Here!

In today’s industrial market, Ethernet cable is in high demand. With words like Ethernet, Ethernet/IP, solid, and stranded, making a decision from the different types of cable can be difficult.

I want to make it easy for you to pick the right cable to go with the network of your choosing.  As a network, Ethernet is easy to install and it is easy to connect to other networks – you can probably even have Ethernet network devices connect to your current network.

So, let’s start with the basics…First, what is the difference between Ethernet and Ethernet/IP?  They both have teal jackets (hence the title – The “Spring Line”) due to the industrial Ethernet standards in North America. So, the difference between the two is in the application.  Ethernet is a good networking cable that transmits data like an internet cable.  Ethernet/IP transmits data and also has an industrial protocol application.  The Industrial Protocol (IP) allows you to transmit more data if you have a lot devices connected to each other or a lot of machines moving at once.  Ethernet/IP resists against UV rays, vibrations, heat, dust, oil, chemical, and other environmental conditions.

Next, there are two kinds of Ethernet IP cables: Solid and Stranded. Solid is great for new applications that require high-speed Ethernet.  The solid cables can transmit and receive across long distances and have a higher data rate compared to stranded.  The downside is that solid cables can break, and do not bend or flex well. Stranded is a better cable if you have to bend, twist, or flex the cable. It’s also better if you have to run short distances.  Stranded is made up of smaller gauge wires stranded together which allows the cable to be flexible and helps protect the cable. They move with the machine and will not break as easily as solid cables.

EthetNetCables_755x220To recap, remember the four short bullet points below when choosing your next cable:

  • Ethernet – transmits data
  • Ethernet/IP – transmits data to many machines/devices
  • Solid – good for long distance and little flexing
  • Stranded– good for short distance and flexing

To learn more visit www.balluff.us

2 Simple Ways to Protect from Arc Flash Hazards

If you are a manager at any level of a manufacturing facility, I hope you are aware of the dangers of arc flash.  For those who are not aware, “an arc flash, also called arc blast or arc fault is a type of electrical explosion that results from a low-impedance connection to ground or another voltage phase in an electrical system.”  Typically this does not occur in 120V situations, but can occur in 480V+ installations if proper precautions are not taken.  Employees can be severely injured or even killed when an accident occurs while working with these kinds of electrical systems.   There are many standards  like OSHA, IEEE and NFPA that regulate these types of situations to provide a safe working environment for the employee.  In addition to those standards, I would propose two simple changes to controls architecture and design to help limit the exposure to working inside an electrical cabinet.

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IO-Link is the USB for Industrial Automation

I’ve recently heard this comparison used a number of times and the parallels are quite interesting.  USB was designed to help standardize a dizzying array of connectors and configurations of supplementary devices that developed during the age of the Compaq vs IBM.  It always took days to configure and establish communication between devices and then finally you could never get all the functionality that the device promised because of your PC’s specific configuration.  USB revolutionized the personal computer by allowing for a standard interface for simple devices from hard-drives to keyboard lights, and best of all by offering a device drivers the functionality promised could be delivered.  If the device broke, you bought a new one, plugged it in and it worked.

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