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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?

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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.

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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.

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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.

Continue reading “IO-Link is the USB for Industrial Automation”

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Linear Position Sensor Case Study

When we talk to people about applications for continuous linear position sensors, we often point out the advantages that can be realized by “upgrading” a machine and/or a process by incorporating continuous position feedback. In this post, I’d like to offer up a case in point. This “Application Spotlight” showcases the real and tangible advantages that can be realized by using continuous linear position sensors, such as:

• Improving machine/process efficiency
• Reducing set-up and changeover time
• Reducing planned downtime
• Error-proofing the process

So, you see, we’re not just making this stuff up! Download this case study here.

Centering Steel Fed into Press
Centering Steel Fed into Press
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Machine Mount I/O: Get out of the Cabinet

In April, Jim Montague of Control Design wrote an interesting article on Machine Mount I/O entitled “Machine-Mount I/O Go Everywhere.”  I think the article makes some very good points as to the value of why someone wants to move from inside an enclosure, or controls cabinet, to mounting I/O products directly on the machine.

He summarizes, with the help of a number of industry experts, the below points:

  • Same or Better control performance out of IP67 products versus IP20 products.  
    • Installation time alone “is reduced by a factor of 5 to 10”
    • Assemble more controls equipment faster with the same people & workspace
  • Smaller & Simpler components take up less real-estate on the machine
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Intelligent Interfaces and IO-Link Innovation

I recently had the opportunity to attend Hannover Fair in Germany and was blown away by the experience… buildings upon buildings of automation companies doing amazing things and helping us build our products faster, smarter and cheaper.  One shining topic for me at the fair was the continued growth of new products being developed with IO-Link communications in them.

All in all, the growth of IO-Link products is being driven by the need of customers to know more about their facility, their process and their production.  IO-Link devices are intelligent and utilize a master device to communicate their specific information over an industrial network back to the controller.  To learn more about IO-Link, read my previous entry, 5 Things You Need to Know about IO-Link.

Continue reading “Intelligent Interfaces and IO-Link Innovation”

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Industrial Network Basics: Simplifying I/O Terminology

There are many terms used for I/O technology in industrial automation: Remote I/O, Distributed I/O,  Modular I/O, Expandable I/O, Block I/O, Conventional I/O and the list can go on.  What do they all mean?  Can they be used interchangeably?  What is the difference?

Lets be honest… this is a muddled topic and many people use different things interchangeably.  I’ve done a bit of research and reading of automation magazines, forums and websites and have tried to piece it together.

Continue reading “Industrial Network Basics: Simplifying I/O Terminology”

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Defining Your Next Network Architecture: Topologies and Global Standard

As many machine builders, OEMs, individual plants, and large corporations decide to move from the “bus” to the “net” (Profibus or DeviceNet to Profinet or EtherNet/IP) they have a chance to look at all the new architectures available and decide on which is the best for them.  Here are the first two topics to take into consideration:

Continue reading “Defining Your Next Network Architecture: Topologies and Global Standard”

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How Ethernet Works… for Dummies

I recently watched a short webinar recorded by the PI North America organization and it really helped me understand the basics of how ethernet communication comes together.  There are so many protocols and standards and they all communicate on the same media.  Carl and Hunter do a good job presenting ethernet in a technical but easy to understand way.

The webinar is here.  Their topics include:

Continue reading “How Ethernet Works… for Dummies”