How IO-Link is Revolutionizing Overall Equipment Efficiency

Zero downtime.  This is the mantra of the food and beverage manufacturer today.  The need to operate machinery at its fullest potential and then increase the machines’ capability is where the demands of food and beverage manufacturers is at today.  This demand is being driven by smaller purchase orders and production runs due to e-commerce ordering, package size variations and the need for manufacturers to be more competitive by being flexible.

Using the latest technology, like IO-Link, allows manufacturers to meet those demands and improve their Overall Equipment Efficiency (OEE) or the percentage of manufacturing time that is truly productive.  OEE has three components:

  1. Availability Loss
    1. Unplanned Stops/Downtime – Machine Failure
    2. Planned Downtime – Set up and AdjustmentsS
  2. Performance Loss
    1. Small Stops – Idling and Minor Stops
    2. Slow Cycles – Reduced Speed
  3. Quality Loss
    1. Production Rejects – Process Defects
    2. Startup Rejects – Reduced Yield

IO-Link is a smart, easy and universal way to connect devices into your controls network.

The advantage of IO-Link is that it allows you to connect to EtherNet/IP, CC-Link & CC-LinkIE Field, Profinet & Profibus and EtherCAT & TCP/IP regardless of the brand of PLC.  IO-Link also allows you to connect analog devices by eliminating traditional analog wiring and provides values in actual engineering units without scaling back at the PLC processor.

Being smart, easy and universal, IO-Link helps simplify controls architecture and provides visibility down to the sensor and device.

IO-Link communicates the following:

  • Process data (Control, cyclical communication of process status)
  • Parameter data (Configuration, messaging data with configuration information)
  • Event data (Diagnostics, Communication from device to master (diagnostics/errors )

This makes it the backbone of the Smart Factory as shown in the graphic below.

 

IO-Link Simplifies the Controls Architecture

IO-Link OEE1

IO-Link OEE2

The Emergence of Device-level Safety Communications in Manufacturing

Manufacturing is rapidly changing, driven by trends such as low volume/high mix, shorter lifecycles, changing labor dynamics and other global factors. One way industry is responding to these trends is by changing the way humans and machines safely work together, enabled by updated standards and new technologies including safety communications.

In the past, safety systems utilized hard-wired connections, often resulting in long cable runs, large wire bundles, difficult troubleshooting and inflexible designs. The more recent shift to safety networks addresses these issues and allows fast, secure and reliable communications between the various components in a safety control system. Another benefit of these communications systems is that they are key elements in implementing the Industrial Internet of Things (IIoT) and Industry 4.0 solutions.

Within a typical factory, there are three or more communications levels, including an Enterprise level (Ethernet), a Control level (Ethernet based industrial protocol) and a Device/sensor level (various technologies). The popularity of control and device level industrial communications for standard control systems has led to strong demand for similar safety communications solutions.

Safety architectures based on the most popular control level protocols are now common and often reside on the same physical media, thereby simplifying wiring and control schemes. The table, below, includes a list of the most common safety control level protocols with their Ethernet-based industrial “parent” protocols and the governing organizations:

Ethernet Based Safety Protocol Ethernet Based Control Protocol Governing Organization
CIP Safety Ethernet IP Open DeviceNet Vendor Association (ODVA)
PROFISafe PROFINET PROFIBUS and PROFINET International (PI)
Fail Safe over EtherCAT (FSoE) EtherCAT EtherCAT Technology Group
CC-Link IE Safety CC-Link IE CC-Link Partner Association
openSAFETY Ethernet POWERLINK Ethernet POWERLINK Standardization Group (EPSG)

 

These Ethernet-based safety protocols are high speed, can carry fairly large amounts of information and are excellent for exchanging data between higher level devices such as safety PLCs, drives, CNCs, HMIs, motion controllers, remote safety I/O and advanced safety devices. Ethernet is familiar to most customers, and these protocols are open and supported by many vendors and device suppliers – customers can create systems utilizing products from multiple suppliers. One drawback, however, is that devices compatible with one protocol are not compatible with other protocols, requiring vendors to offer multiple communication connection options for their devices. Other drawbacks include the high cost to connect, the need to use one IP address per connected device and strong influence by a single supplier over some protocols.

Device level safety protocols are fairly new and less common, and realize many of the same benefits as the Ethernet-based safety protocols while addressing some of the drawbacks. As with Ethernet protocols, a wide variety of safety devices can be connected (often from a range of suppliers), wiring and troubleshooting are simplified, and more data can be gathered than with hard wiring. The disadvantages are that they are usually slower, carry much less data and cover shorter distances than Ethernet protocols. On the other hand, device connections are physically smaller, much less expensive and do not use up IP addresses, allowing the integration into small, low cost devices including E-stops, safety switches, inductive safety sensors and simple safety light curtains.

Device level Safety Protocol Device level Standard Protocol Open or Proprietary Governing Organization
Safety Over IO-Link/IO-Link Safety* IO-Link Semi-open/Open Balluff/IO-Link Consortium
AS-Interface Safety at Work (ASISafe) AS-Interface (AS-I) Open AS-International
Flexi Loop Proprietary Sick GmbH
GuardLink Proprietary Rockwell Automation

* Safety Over IO-Link is the first implementation of safety and IO-Link. The specification for IO-Link Safety was released recently and devices are not yet available.

The awareness of, and the need for, device level safety communications will increase with the desire to more tightly integrate safety and standard sensors into control systems. This will be driven by the need to:

  • Reduce and simplify wiring
  • Add flexibility to scale up, down or change solutions
  • Improve troubleshooting
  • Mix of best-in-class components from a variety of suppliers to optimize solutions
  • Gather and distribute IIoT data upwards to higher level systems

Many users are realizing that neither an Ethernet-based safety protocol, nor a device level safety protocol can meet all their needs, especially if they are trying to implement a cost-effective, comprehensive safety solution which can also support their IIoT needs. This is where a safety communications master (or bridge) comes in – it can connect a device level safety protocol to a control level safety protocol, allowing low cost sensor connection and data gathering at the device level, and transmission of this data to the higher-level communications and control system.

An example of this architecture is Safety Over IO-Link on PROFISafe/PROFINET. Devices such as safety light curtains, E-stops and safety switches are connected to a “Safety Hub” which has implemented the Safety Over IO-Link protocol. This hub communicates via a “black channel” over a PROFINET/IO-Link Master to a PROFISafe PLC. The safety device connections are very simple and inexpensive (off the shelf cables & standard M12 connectors), and the more expensive (and more capable) Ethernet (PROFINET/PROFISafe) connections are only made where they are needed: at the masters, PLCs and other control level devices. And an added benefit is that standard and safety sensors can both connect through the PROFINET/IO-Link Master, simplifying the device level architecture.

Safety

Combining device level and control level protocols helps users optimize their safety communications solutions, balancing cost, data and speed requirements, and allows IIoT data to be gathered and distributed upwards to control and MES systems.

 

Connecting Safety Devices to a Safety Hub

Safety device users face a dilemma when selecting safety components: They want to create a high-performance system, using best-in-class parts, but this often means buying from multiple suppliers. Connecting these devices to the safety control system to create an integrated system can be complicated and may require different cabling/wiring configurations, communications interfaces and/or long, hardwired cables.

Device-Level Protocols

One solution, discussed in a previous blog on industrial safety protocols, is to connect devices to an open, device-level protocol such as Safety Over IO-Link or AS-i Safety At Work. These protocols offer a simple way to connect devices from various suppliers using non-proprietary technologies. Both Safety Over IO-Link and AS-i Safe offer modules to which many third party devices can be connected.

Connecting to a Safety HubSafety-Arch_012518

The simplest way to connect to a safety hub/module is to buy compatible products from the hub supplier. Many safety block/hub suppliers also offer products such as E-stops, safety light curtains, door switches, inductive safety sensors and guard locking switches which may provide plug & plug solutions. There are, however, also many third party devices which can also be easily connected to some of these hubs. Hubs which are AIDA (Automation Initiative of German Domestic Automobile manufacturers) compliant allow connection of devices which are compatible with this standard. Generally, these devices have M12 connectors with 4, 5 or 8 pins, and the power, signal and ground pins are defined in the AIDA specifications. Most major safety device manufacturers offer at least one variant of their main products lines, which are AIDA pin-compatible.

AIDA/Safety Hub Compatible Devices

Some suppliers have lists of devices which meet the M12 pin/connector AIDA specification and may be connected to AIDA compatible modules. Note that not all the listed safety devices may have been tested with the safety blocks/hubs, but their specifications match the requirements. AIDA compatible devices have been identified from all major safety suppliers including Balluff, Rockwell, Sick, Schmersal, Banner, Euchner and Omron STI; and range from safety light curtains to door switches to E-stop devices.

Easy Connection

While some manufacturers prefer to focus on locking customers into a single supplier solution, many users want to combine devices from multiple suppliers in a best-in-class solution. Selecting a safety I/O block or hub which supports AIDA compatible devices makes it fast and easy to connect a wide range of these devices to create the safety system that is the best solution for your application.

Why IO-Link is the Best Suited Technology for Smart Manufacturing

While fieldbus solutions utilize sensors and devices with networking ability, they come with limitations. IO-Link provides one standard device level communication that is smart in nature and network independent. That enables interoperability throughout the controls pyramid, making it the most suitable choice for smart manufacturing.

IO-Link offers a cost effective solution to the problems. Here is how:

  • IO-Link uses data communication rather than signal communication. That means the communication is digital with 24V signal with high resistance to the electrical noise signals.
  • IO-Link offers three different communication modes: Process communication, Diagnostic communication (also known as configuration or parameter communication), and Events.
    • Process communication offers the measurement data for which the device or sensor is primarily selected. This communication is cyclical and continuous in nature similar to discrete I/O or analog communication.
    • Diagnostic communication is a messaging (acyclic) communication that is used to set up configuration parameters, receive error codes and diagnostic messages.
    • Event communication is also acyclic in nature and is how the device informs the controller about some significant event that the sensor or that device experienced.
  • IO-Link is point-to-point communication, so the devices communicate to the IO-Link master module, which acts as a gateway to the fieldbus or network systems or even standard TCP/IP communication system. So, depending on the field-bus/network used, the IO-Link master may change but all the IO-Link devices enjoy the freedom from the choice of network. Power is part of the IO-Link communication, so it does not require separate power port/drop on the devices.
  • Every open IO-Link master port offers expansion possibilities for future integration. For example, you could host an IO-Link RFID device or a barcode reader for machine access control as a part of a traceability improvement program.

For more information, visit www.balluff.com/io-link.

The Need for Data and System Interoperability in Smart Manufacturing

As technology advances at a faster pace and the world becomes flatter, manufacturing operations are generally focused on efficient production to maximize profitability for the organization. In the new era of industrial automation and smart manufacturing, organizations are turning to data generated on their plant floors to make sound decisions about production and process improvements.

Smart manufacturing improvements can be divided roughly into six different segments: Predictive Analytics, Track and Trace, Error Proofing, Predictive Maintenance, Ease of Troubleshooting, and Remote Monitoring.IOLink-SmartManufacturing_blog-01To implement any or all of these improvements requires interoperable systems that can communicate effectively and sensors and devices with the ability to provide the data required to achieve the manufacturer’s goals. For example, if the goal is to have error free change-overs between production cycles, then feedback systems that include identification of change parts, measurements for machine alignment changes, or even point of use indication for operators may be required.  Similarly, to implement predictive maintenance, systems require devices that provide alerts or information about their health or overall system health.

Traditional control system integration methods that rely heavily on discrete or analog (or both) modes of communication are limited to specific operations. For example, a 4-20mA measurement device would only communicate a signal between 4-20mA. When it goes beyond those limits there is a failure in communication, in the device or in the system. Identifying that failure requires manual intervention for debugging the problem and wastes precious time on the manufacturing floor.

The question then becomes, why not utilize only sensors and devices with networking ability such as a fieldbus node? This could solve the data and interoperability problems, but it isn’t an ideal solution:

  • Most fieldbuses do not integrate power and hence require devices to have separate power drops making the devices bulkier.
  • Multiple fieldbuses in the plant on different machines requires the devices to support multiple fieldbus/network protocols. This can be cost prohibitive, otherwise the manufacturer will need to stock all varieties of the same sensor.
  • Several of the commonly used fieldbuses have limitations on the number nodes you can add — in general 256 nodes is capacity for a subnet. Additional nodes requires new expensive switches and other hardware.

IOLink-SmartManufacturing_blog-02IO-Link provides one standard device level communication that is smart in nature and network independent, thus it enables interoperability throughout the controls pyramid making it the most suitable choice for smart manufacturing.

We will go over more specific details on why IO-Link is the best suited technology for smart manufacturing in next week’s blog.

 

Safely Switch Off Cylinders While Transmitting Field Data

Is it possible to safely switch off cylinders while simultaneously transmitting field data and set up the system in accordance with standards? Yes!

In order to rule out a safety-critical fault between adjacent printed circuit board tracks/contact points (short circuit) according to DIN EN ISO 13849, clearance and creepage distances must be considered. One way to eliminate faults is to provide galvanic isolation by not interconnecting safety-relevant circuits/segments. This means  charge carriers from one segment cannot switch over to the other, and the separation makes it possible to connect the safety world with automation — with IO-Link. Safely switching off actuators and simultaneously collecting sensor signals reliably via IO-Link is possible with just one module. To further benefit from IO-Link and ensure safety at the same time, Balluff’s I/O module is galvanically isolated with a sensor and an actuator segment. The two circuits of the segments are not interconnected, and the actuator segment can be safely switched off without affecting the sensors. Important sensor data can still be monitoring and communicated.

The topological structure and the application of this safety function is shown in this figure as an example:

2D-SAGT-Betriebsanleitung_v2

  1. A PLC is connected to an IO-Link master module via a fieldbus system.
  2. The IO-Link master is the interface to all I/O modules (IO-Link sensor/actuator hubs) or other devices, such as IO-Link sensors. The IO-Link communication takes place via a standardized M12 connector.
  3. Binary switching elements can be connected to the galvanically isolated sensor/actuator hub (BNI IOL-355). The four connection ports on the left correspond to the sensor segment and the four ports on the right correspond to the actuator segment. Communication of the states is done via IO-Link.
  4. The power supply for both segments takes place via a 7/8″ connection, whereby attention must be paid to potential separated routing of the sensor and actuator circuits. Both the power supply unit itself and the wiring to the IO-Link device with the two segments must also ensure external galvanic isolation. This is made possible by separating the lines with a splitter.
  5. An external safety device is required to safely interrupt the supply voltage of the actuator segment (four ports simultaneously). Thus, the module can implement safety functions up to SIL2 according to EN62061/PLd and ISO 13849.  For example, this can happen through the use of a safety relay, whereby the power supply is safely disconnected after actuation of peripheral safety devices (such as emergency stops and door switches). At the same time, the sensor segment remains active and can provide important information from the field devices.

The module can handle up to eight digital inputs and outputs. If the IO-Link connection is interrupted, the outputs assume predefined states that are retained until the IO-Link connection is restored. Once the connection is restored, this unique state of the machine can be used to continue production directly without a reference run.

An application example for the interaction of sensors and actuators in a safety environment is the pneumatic clamping device of a workpiece holder. The position feedback of the cylinders is collected by the sensor segment, while at the same time the actuator segment can be switched off safely via its separately switchable safety circuit. If the sensor side is not required for application-related reasons, galvanically isolated IO-Link modules are also available with only actuator segments (BNI IOL 252/256). An isolated shutdown can protect up to two safety areas separately.

 

Industrial Safety Protocols

There are typically three or more communication levels in the modern factory which consist of:

  • Enterprise level (Ethernet)
  • Control level (Ethernet based industrial protocol)
  • Device/sensor level (various technologies)

IO-Link

The widespread use of control and device level communications for standard (non-safety) industrial applications led to a desire for similar communications for safety. We now have safety versions of the most popular industrial control level protocols, these make it possible to have safety and standard communications on the same physical media (with the appropriate safety hardware implemented for connectivity and control). In a similar manner, device level safety protocols are emerging to allow standard and safety communications over the same media. Safety Over IO-Link and AS-i Safety At Work are two examples.

This table lists the most common safety control level protocols with their Ethernet-based industrial “parent” protocols and the governing organizations:

chart1

And this table lists some of the emerging, more well-known, safety device level protocols with their related standard protocols and the governing or leading organizations:

Chart2
* Safety Over IO-Link is the first implementation of safety and IO-Link. The specification for IO-Link Safety was released recently and devices are not yet available.

Ethernet-based safety protocols are capable of high speed and high data transmission, they are ideal for exchanging data between higher level devices such as safety PLCs, drives, CNCs, HMIs, motion controllers, remote safety I/O and advanced safety devices. Device level protocol connections are physically smaller, much less expensive and do not use up IP addresses, but they also carry less data and cover shorter distances than Ethernet based protocols. They are ideal for connecting small, low cost devices such as E-stops, safety switches and simple safety light curtains.

As with standard protocols, neither a control level safety protocol, nor a device level safety protocol can meet all needs, therefore cost/performance considerations drive a “multi-level” communications approach for safety. This means a combined solution may be the best fit for many safety and standard communications applications.

A multi-level approach has many advantages for customers seeking a cost-effective, comprehensive safety and standard control and device solution which can also support their IIoT needs. Users can optimize their safety communications solutions, balancing cost, data and speed requirements.

Installation and device replacement – easy and safe

The development and design of a machine is followed by the assembly and commissioning phase. Commissioning is especially time consuming, but the replacement of components or devices can be so as well.

This often raises the question of how to simplify commissioning and optimize component replacement.

The answer is provided by the IO-Link communication interface. IO-Link is the first globally standardized IO technology (IEC 61131-9) that communicates from the controller down to the lowest level.

But how exactly does this help with commissioning and component replacement? This is very simple and will be explained now. Let’s start first with the assembly, installation and commissioning phase.

Easy installation

During installation, the individual components must be electrically connected to each other. While fieldbus use has simplified the installation process, generally speaking, fieldbus cables have a low signal level, are susceptible to interference, have little flexibility, and are expensive due to their shielding. This is where IO-Link comes into play. Because the weaknesses of a fieldbus protocol are negligible with IO-Link.

Included in an IO-Link system are an IO-Link master and one or several IO-Link devices such as sensors or actuators. The IO-Link master is the interface to the controller (PLC) and takes over communication with connected IO-Link devices. The interface uses unshielded, three- or four-conductor standard industrial cables. Therefore the standard communication interface can be integrated into the fieldbus world without effort. Even complex components can be easily connected in this way. In addition, the standard industrial cables are highly flexible and suitable for many bending cycles. Three wires are the standard for the communication between the devices and the IO-Link master and for the power supply voltage. These are easy to connect, extremely cost-effective and their connection is standardized with M5, M8 or M12 connectors.

The commissioning will also be supported by IO-Link. The devices can be parameterized quickly and easily through parameter maintenance or duplication. Annoying manual adjustment of the sensors and actuators is no longer necessary. This saves money and avoids errors. The parameters of the individual devices are stored in the PLC or directly in the IO-Link master and can, therefore, be written directly to the sensor.

Now that we have clarified the advantages of IO-Link during commissioning, we will take a look at the replacement of components.

Communication with IO-Link

Save device replacement during operation

A sensor replacement directly leads to machine downtime. IO-Link enables quick and error-free replacement of sensors. The parameters of a replaced IO-Link sensor are automatically written from the IO-Link master or the PLC to the new sensor. The accessibility of the sensor does not play a major role anymore. In addition, IO-Link devices cannot be mixed up, since they are automatically identifiable via IO-Link.

Efficient format and recipe changes

IO-Link offers ideal properties that are predestined for format adjustment: sufficient speed, full access to all parameters, automatic configuration, and absolute transmission of the measured values. This eliminates the need for time-consuming reference runs. Since the machine control remains permanently traceable, the effort required for error-prone written paper documentation is also saved. Format changes and recipe changes can be carried out centrally via the function blocks of the PLC.

To learn more about the advantages of IO-Link, visit balluff.us/io-link.

 

Maintain Machine Up-Time with Application-Specific Cables

Using high-durability cables in application environments with high temperatures, weld spatter, or washdown areas improves manufacturing machine up-time.

It is important to choose a cable that matches your specific application requirements.

Washdown Applications

When a food and beverage customer needs to wash down their equipment after a production shift, a standard cable is likely to become a point of failure. A washdown-specific cable with an IP68/IP69 rating is designed to withstand high-pressure cleaning. It’s special components, such as an internal O-ring and stainless-steel connection nut, keep water and cleaners from leaking.

Welding Applications

Welding environments require application-specific cables to deal with elevated temperatures, tight bend radiuses and weld spatter. Cables with a full silicone jacket prevent the build-up of debris, which can cause shorts and failures over time.

High Temperature cables

Applications with high temperatures require sensors that can operate reliably in their environment. The same goes for the cables. High temperature cables include added features such as a high temperature jacket and insulation materials specifically designed to perform in these applications.

Cables

Selecting the correct cable for a specific application area is not difficult when you know the requirements the application environment demands and incorporate those demands into your choice. It’s no different than selecting the best sensor for the job. The phrase to remember is “application specificity.”

For more information on standard and high-durability cables, please visit www.balluff.com.

 

Back to the Basics: IO-Link

In the last post about the Basics of Automation, we learned how distances, travel, angles and pressures can be measured contactlessly, whether linear or rotary. In this blog, let’s take a closer look at IO-Link technology.

Throughout the history of manufacturing, as the level of automation increased, the demand for intelligent field devices grew. A variety of interfaces with different mechanical and electrical characteristics were created, and the need for standardization grew. The cooperative work of several companies developed the viable solution. Like  USB in the PC world, IO-Link in automation leads to a considerable simplification of installation with simultaneously extended diagnostics and parameterization capability.

IO-Link 1

It’s a worldwide standardized I/O technology according to IEC 61131-9, in order to communicate from the control to the lowest level of automation. The universal interface is a fieldbus independent point-to-point connection that works with an unshielded industrial cable. The IO-Link Community founded in 2006, consisting of leading automation manufacturers, promotes IO-Link with the acronym “”USE””:

  • Universal – IO-Link is an international standard (IEC 61131-9)
  • Smart – IO-Link enables diagnostics and parameter-setting of devices
  • Easy – IO-Link provides great simplification and cost reduction

System Components

IO-Link master
Also mentioned as the heart of the IO-Link installation, it communicates with the controller via the respective fieldbus as well as downward using IO-Link to the sensor/actuator level.

Sensors and Actuators
The IO-Link capable intelligent sensors and actuators are connected directly to the IO-Link master via IO-Link. This enables the simplest installation, the best signal quality, parameterization and diagnostics.

Hubs
The sensor/actuator hub exchanges signals with the binary and/or analog sensors and actuators and communicates with the IO-Link master.

IO-Link 2

To learn more about the Basics of Automation, visit www.balluff.com.