PROFINET growth continues to accelerate year over year across all industry verticals. Read about the technology below that fuels this success.
§1.0 – PROFINET What & Why
PROFINET is the world’s most advanced Industrial Ethernet solution. It is a communication protocol to exchange data between controllers and devices. Controllers can be PLCs, DCSs, or PACs. Devices can be I/O blocks, vision systems, RFID readers, drives, process instruments, proxies, or even other controllers. PROFINET is fully compatible with – and leverages all the features of – office Ethernet. However there are differences, office Ethernet is not capable of real time performance for industrial automation. Office Ethernet is also much less able to withstand harsh industrial environments.
Based on its experiences with PROFIBUS, a real time fieldbus that is the most popular automation networking solution in automation today, PI Working Groups comprising more than 500 experts from major automation suppliers spent many years creating a comprehensive real time Ethernet solution for automation: PROFINET.
This solution is able to operate in the difficult industrial environments and is capable of delivering the speed and precision required by manufacturing plants. It can also provide additional functions – for example, Safety, Energy Management, and IT Integration. These can be used in combination with the control and monitoring functions. Users have a choice on which services they would like to utilize.
Here are some other advantages of working with PROFINET at the IO level:
- Highly scalable architectures
- Access to field devices over the network
- Maintenance and servicing from anywhere (even over the internet)
- Best in class diagnostics
- Lower costs for production/quality data monitoring
§1.1 – Real Time Performance
PROFINET meets the demands of IT and plant floor automation using three communications channels:
- Standard TCP/IP: Suitable for non-deterministic functions such as parametrization, video/audio transmissions and data transfer to higher level IT systems.
- Real Time (PROFINET RT): TCP/IP layers are bypassed in order to have a deterministic performance for automation applications in the 1-10 ms range. This represents a software-based solution suitable for typical I/O applications, including motion control and high-performance requirements.
- Isochronous Real Time (PROFINET IRT): Signal prioritization and scheduled switching deliver high precision synchronization for applications such as motion control. Cycle rates in the sub-millisecond range are possible, with jitter in the microsecond range. This service requires hardware support in the form of (readily-available) ASICs.
All three communication channels can be used simultaneously. Bandwidth sharing ensures that at least 50% of every I/O cycle remains available for TCP/IP communications. Combined with ruggedized cabling, connectors, and Ethernet switches, PROFINET can meet all the needs of automation. Further below you can read about PROFINET’s features, which make it the world’s most advanced Industrial Ethernet.
It’s important to understand that PROFINET is fully compliant with internationally-accepted Ethernet standards. Some Industrial Ethernets break Ethernet conventions and are not truly compatible with office-based systems. These cannot interoperate as easily within enterprise architectures, or indeed alongside those Industrial Ethernets which are fully compliant.
Read more on PROFINET Real Time Here:
§1.2 – Different from Office Ethernet
As fieldbus adoption grew, users realized that tighter integration with IT would become more and more important. Fieldbus systems can be integrated into plant networking hierarchies using gateways and other devices but that approach can be cumbersome and expensive. Therefore, users wondered if office networking technologies – i.e. Ethernet – could be brought onto the plant floor. The ideal scenario, they argued, was for automation systems themselves to be based on Ethernet.
Actually, Ethernet has been used on the factory floor almost as long as it has been used in the office, though mainly for inter-cell communications and not for IO. There has never been a standardized way to implement it, installations have tended to be proprietary. In addition, there are practical difficulties, including:
- Office Ethernet cannot deliver the real time performance needed for industrial IO.
- Office Ethernet cannot meet the high precision determinism needed for advanced motion control.
- Office Ethernet is unable to withstand the physical conditions found in manufacturing environments (dusty, hot, humid, corrosive, EMI, etc).
Fortunately, all these difficulties can be overcome, leading to what we now know as ‘Industrial Ethernet’.
Read this white paper for more information on Industrial Ethernet:
§1.3 – Fieldbus: What & Why
Fieldbus is a digital industrial networking technology for transporting data between control devices (such as a PLC or DCS) and field devices (such as I/O, drives, actuators and transmitters) for the purposes of controlling production lines and equipment. By improving communications between these devices, a fieldbus facilitates significant improvements in the way plants are controlled, monitored and managed in both process and factory automation environments.
The advantages of fieldbus include its ability to connect multiple devices over a single cable or ‘bus’. This factor alone can cut design, engineering, commissioning, and maintenance costs by up to 40%. The greater accuracy of ‘digital’ also means big improvements in production speeds and quality, while better diagnostics allow fieldbus-connected production lines to benefit from advanced asset management techniques. Fieldbus can also deliver the real-time performance demanded by current automation environments.
PROFIBUS, the world’s most widely used fieldbus, was introduced in 1989 and is standardized under IEC61158. It is supported by more than 1400 equipment vendors around the world. The single standardized approach means users have a wide choice of vendors and products, factors that encourage higher performance and lower costs. A fieldbus-enabled plant also delivers more and better data to supervisory systems, to support improved management strategies across the enterprise.
The vast field experience gained from PROFIBUS is embedded deeply in the PROFINET solutions available today.
More on Fieldbuses in this white paper:
§1.4 – Coexistence
Because PROFINET is fully compatible with office Ethernet, it can reside (and be fully operational) on a single network cable alongside other Industrial Ethernet’s that are also based on standard Ethernet. There are several of these, including EtherNet/IP and Modbus/TCP.
However, ‘coexistence’ does not mean different systems are ‘interoperable’. It means only that it is possible to use the same network infrastructure to support multiple Industrial Ethernets. Protocol differences mean that Industrial Ethernets cannot communicate with each other except by using additional hardware such as protocol converters.
It’s also important to recognize that some Industrial Ethernets do not conform with the international Ethernet standard and that these require deployment on a closed network. Although these are not necessarily ‘proprietary’, they are non-standard from an Ethernet point of view.
Learn more with this PROFINET and IT white paper:
§1.5 – Free Training across North America
Over 16 free one-day training classes for PROFINET are given across North America throughout the year. They serve to educate and assist in all technical aspects of using the PROFINET. The class is specifically designed for end users, machine builders, system integrators and manufacturers of automation devices. All students receive a training manual that includes a hard copy of presentations plus additional documentation in network design, installation, commissioning, and security guide manuals.
- Industry 4.0
- PROFINET Overview
- PROFINET Isochronous Real-Time(IRT)
- PROFINET in practice
- Profiles: PROFIsafe, PROFIenergy, and PROFIdrive
- Infrastructure: Wiring and Installation, Topology
- Process Automation
- Future Trends
§2.0 – Features
PROFINET was developed by PI Working Groups involving over 500 engineers from major automation vendors. Their vast field experience with PROFIBUS was used as the starting point. Ethernet’s particular attributes were then selectively incorporated to meet the specific needs of automation.
PROFINET delivers a rich set of specialized features that sit on top of other communications. They are aimed at automation applications of all types and designed to make life easier for the designer, engineer, maintenance staff, and manager. You don’t have to use all the features at once – just choose what you need to meet your particular circumstances. Some features are listed below:
- iPar server: Individual Parameter Server for automatic parameter assignment of devices
- Configuration in run: Allows a device to be configured and set up even with the controller in run
- Shared device: Distribution of device functions to various controllers
- Application profiles: Safety, energy management, motion control, etc
- Redundancy: Device, controller, media, and network redundancy options
- Simple device replacement: Allows a controller to automatically name a replaced IO device in case of device failure and replacement
- Tool calling interface: Used to call up a device-specific engineering tool
- and many more…
Think of PROFINET as a modular solution, offering the flexibility to start simple and add functionality as required.
More details on specific features and highlights Here:
§2.1 – Handling I/O
PROFINET treats I/O very much like PROFIBUS does. An engineering tool is associated with the controller and obtains information about the IO Devices from a GSD file just like PROFIBUS does. After a project is configured in the software, it is downloaded to the controller. The controller can then communicate with the I/O Devices. The I/O Devices are structured hierarchically as Device, Module, and Channel. Inputs and Outputs are exchanged between the controller and I/O Device as ‘cyclic’ data. The controller sets the update cycle time. Additional information such as diagnostic data that is not required as frequently is communicated as ‘acyclic’ data.
Additional details on the PROFINET System Description:
§2.2 – Wireless
Wireless is part of PROFINET’s specification for two well established wireless standards: Wi-Fi and Bluetooth. The use of standardized wireless technology has no restrictions compared to normal cabling. Also, PI is active in helping standardize wireless networking solutions for industrial applications in both Process and Factory Automation arenas.
In Process Automation
PI is a primary supporter of the WirelessHART protocol (ISA 100.11a). A standard adapter interface for WirelessHART has been agreed by PI in conjunction with other process automation organizations including HART Communication Foundation and Fieldbus Foundation. Therefore, users benefit from a single technology offer from multiple vendors.
In Discrete Automation
Factory Automation differs from process in many respects. For example, bandwidth requirements are greater and network resilience, security, and redundancy are critical. As with the enterprise, WiFi and Bluetooth solutions are already used in factory situations. In addition, a set of standards is currently being developed by PI Working Groups for sensor/actuator communications in conjunction with both PROFIBUS and PROFINET. Bluetooth has been selected as the communications medium, complemented by IO-Link as the interface to end devices.
Watch this webinar on Industrial Wireless Networking:
§2.3 – Diagnostics
PROFINET offers an unprecedented level of diagnostics capability, both locally and remotely using standardized displays.
Diagnostic overviews provide levels of detail according to your needs, showing device, module, channel and interrupt activity. Current fault events can be acknowledged and PROFINET’s I&M (Identification and Maintenance) functions are facilitated at the same time. Comprehensible naming conventions mean you don’t have to look up obscure tag names or numbers before getting down to business. Even topology layouts showing the geography of your plant network become possible with PROFINET.
Integrated web servers are incorporated in automation devices and these mean that a standard Internet browser can be used to access diagnostic displays. It also means that engineers don’t necessarily have to be on site in order to diagnose a fault as access to plant networks can easily be facilitated over an intranet or even the internet. Automated, event-driven messages can be dispatched by SMS or e-mail to your engineering staff.
Cable diagnostics are just as simple. Again, displays are standardized to give accurate topology views of the network for fast location of faults. Standard Ethernet tools such as SNMP and Ethereal can be utilized. There’s also easy access to vendor-specific tools for complex devices.
Watch this webinar on Diagnostics:
§2.4 – Vertical Integration
PROFINET is fully compatible with standard Ethernet, hence it can provide classic TCP/IP performance whenever required. Consequently, it is easily scaled to match the needs of almost any size manufacturing facility. In addition, PROFINET networks are easily integrated with existing Ethernet networks such as higher level enterprise systems including MES and ERP (Manufacturing Execution Systems and Enterprise Resource Planning). Within reason, and working within your own security and management strategies, it is possible for PROFINET to reach across the enterprise.
With PROFINET, production data can be made available to supervisory staff in real time from almost anywhere in the enterprise. This can provide better management of plant, skills, and assets and lead to improved production scheduling and order processing. PROFINET can even deliver full Internet connectivity, enabling global enterprises to operate more efficiently across the globe.
Read White Paper:
§2.5 – PROFIenergy
PROFIenergy offers a completely new way of saving energy in automation systems. With PROFIenergy, automation controllers on a PROFINET network determine when end devices are switched into ‘sleep’ or OFF modes to save on energy usage during:
- Expected short breaks – e.g. lunchtime and shift changes
- Planned longer breaks – e.g. nights and weekends
- Unplanned pauses – e.g. breakdowns, maintenance, and upgrades
By defining a standardized open profile, PI has made it possible for vendors and users to collaborate on intelligent energy management strategies using PROFIenergy.
- Energy and cost savings
- Fulfill laws/regulations for environmental protection
- Easy to program – using loadable function blocks
- Competitive Advantage
Device Maker Benefits
- Unique selling proposition and competitive advantage
- Builds on existing PROFINET protocol
PROFINET transmits standardized PROFIenergy commands to end devices and receives back status information and energy consumption data. PROFIenergy data uses the acyclic slots of the PROFINET communications protocol and it does not interfere with normal PROFINET processes. PROFIenergy can, therefore, be fully integrated into existing automation architectures.
PROFIenergy can be used to balance energy demand and match peak load conditions to avoid costly penalties.
For more information, read this white paper on PROFIenergy:
§2.6 – Fast Start-Up
PROFINET Fast Start Up (FSU) feature allows IO Device to go instantly into a ‘power on’ state in response to signals from an IO Controller. Such functionality is a high priority for industrial robots with Automatic Tool Change (ATC) since it can increase the flexibility of production lines and reduce the number of robots per cell.
In car body production, the total cycle time for a single robot cell can be as low as 45 seconds (including the delay for tool change). Many Industrial Ethernets suffer from slow start up, typically in the range of seconds compared with 100 ms range for fieldbuses, and this can be too slow for many production needs. By optimizing the PROFINET protocol and how data is utilized by end devices it is possible to reduce start up times dramatically.
PROFINET FSU defines the time between ‘power on’ and receipt of the first cyclic input data to be less than 500 ms. The protocol optimizations needed to achieve this are standardized in the PROFINET specification as follows:
- Use of fixed transmission parameters (only for copper wires), instead of automatic detection, which reduces start up by up to three seconds.
- The network address is not passed to the IO device on every cycle, but only at first start up. Parameters are stored in the IO device memory and re-used. This may save several seconds.
- IO Devices announce their readiness to establish communication instead of waiting for the IO Controller to search. It is possible to save up to one second this way.
From the OEM/end-user point of view, a number of other optimizations are possible. For example, start up can also be reduced through the use of suitable hardware. Wireless may also help, either by keeping communication up all the time or by establishing communication in advance of ‘power on’.
§2.7 – Security
The openness of Ethernet guarantees easy access from anywhere in the world using readily available tools such as web browsers. This great advantage has implications for the security of networks across the enterprise.
PROFINET addresses these sometimes critical security issues in various ways, as defined in a special security specification:
- By guarding against errors and improper operation
- By preventing unauthorized access that could lead to network manipulation or espionage
- By using proven and certified security standards (e.g. firewalls and VPN)
With these measures, the integrity of a PROFINET control network can be fully protected, without presenting any restrictions to personnel who rightfully needs access.
Read the PROFINET security guideline Here:
§2.8 – Safety
Safety systems protect equipment, people, and the environment. Traditionally, they rely on separately wired circuits that are expensive to build, commission, and maintain. Nowadays functional safety can be done over the bus shifting from safety in hard relays to safety in logic. Adding functional safety to an existing automation network means less engineering effort, reduced cabling, faster commissioning and easier maintenance. Networked safety systems also offer greater flexibility, safety strategies can be easily zoned, partitioned, and changed. Innovative safety architectures become possible with new generations of safety devices such as laser scanners.
PROFIsafe is an additional software layer that provides functional safety over the bus on top of existing PROFIBUS and PROFINET protocols. PROFIsafe ensures the integrity of failsafe signals transmitted between safety devices and a safety controller meeting the relevant safety standards. It works independently of any automation functions even though it is running on the same network. It can be used with either PROFINET or PROFIBUS, in combination if required, in factory and process automation applications.
PROFIsafe has been available since 2001 and nearly 9 million PROFIsafe devices are operational. PROFIsafe is approved for wireless transmission channels such as WLAN and Bluetooth. It can even be used on open Industrial Ethernet backbones.
Please note: Safety is a sensitive area of automation. The dissemination, implementation, and deployment of PROFIsafe technology must be treated seriously. All companies and institutions involved with PROFIsafe conduct themselves according to the PROFIsafe Policy.
More about how PROFIsafe works
- PROFIsafe meets the highest safety categories: up to SIL3 according to IEC 61508 / IEC 62061, or Category 4 according to EN 954-1, or PL “e” according to ISO 13849-1.
- The PROFIsafe profile reduces error probabilities in the data being transmitted between F-devices and F-controllers to the level required by, or better than, relevant safety standards. A series of safety checks are carried out by the PROFIsafe protocol to ensure this.
- PROFIsafe does not have any impact on standard bus protocols and the automation system connected to the same network operates as normal without interference.
- All F-devices and F-controllers are tested for conformance to the PROFIsafe protocol by PI Test Laboratories and certified by PI for use in the field.
- Safety and standard data on the same cable. Also, safety and standard modules can be mixed in one station
Learn more with the PROFIsafe System Description:
§2.9 – Simple Device Replacement
Automation networks are built to run continuously for many years. But, over long periods, automation components can fail or get damaged. The Simple Device Replacement feature is unique within the industry. It allows users to replace PROFINET devices in a fast and effortless manner.
If a device fails, the failed device can be replaced with a new device, without any user configuration. When the user manually replaces the failed device for a new one, the controller detects the new device and assigns the respective IP address, name, and related configuration. There is no need to use engineering tools or reconfigure the network.
There are three requirements for using this feature:
- The replacement device must be the same as the device it is replacing
- The replacement device must have a blank name
- The controller must support Simple Device Replacement
Users can bypass the second requirement by using a controller function. Controllers give the option to allow for name overwrite. If that option is enabled, then the replacement device can have an existing name.
§2.10 – Process Automation
PROFINET is often used in process plants as the main network backbone, but PROFIBUS PA is still used where no Industrial Ethernet can go – into hazardous areas. Not a limitation of PROFINET, but a limitation of Ethernet, since Ethernet was never designed as a hazardous area network.
PROFINET provides a high-speed, high-bandwidth, backbone for PROFIBUS PA (and other fieldbus networks) similar to the way that PROFIBUS DP does! It differs slightly however by using a ‘proxy’ interface – a module that sits between PROFINET and the underlying bus. The data path via the proxy is fully transparent, instruments on the fieldbus appear directly connected to the PROFINET controller as remote IO. This makes configuration, maintenance, and management of an automation system very simple from any part of the enterprise. Proxies exist for PROFIBUS PA and for many other bus technologies including Foundation Fieldbus and WirelessHART. The great advantage of the proxy approach is that existing field networks do not have to be replaced when upgrading a plant to PROFINET, investments in skills and inventory are protected as the migration to Industrial Ethernet architectures occurs.
Moreover, the PROFINET backbone can be used to connect other field devices typically found in process applications – for example, drives and discrete IO. Since most process plants are ‘hybrid’ (they include both process and discrete automation elements) only one network – PROFINET – is needed to cover the entire plant.
Three key additional needs of process automation are also supported by PROFINET:
- Configuration in Run (CiR): The ability to make changes to an application program without stopping the controller.
- Time Sync / Time Stamping: The ability to record the actions, alarms and status messages to a sequence of events.
- Fieldbus integration: Investment protection through the integration of plant units using proxies.
- Scalable Redundancy: PROFINET already has media redundancy but needs to support system redundancy as well for process applications.
Read all about PROFINET in Process:
§3.0 – PROFINET Project
Designing and engineering a PROFINET project is straightforward, especially if you already have fieldbus experience. Migrating from a fieldbus to Industrial Ethernet is particularly easy. Even those who don’t have any experience should rapidly pick up the theory and practice of PROFINET. In this section, we’ll talk you through the basics. Our Resources will then give you all you need to understand what to do and how to do it.
Remember, PROFINET offers a modular approach to automation. That means it’s flexible and versatile. Not everything needs to be utilized so, ‘start slowly and build’.
Watch this webinar:
§3.1 – Designing
Ethernet is a highly scalable and versatile communications technology. It can be deployed in line, tree, tree and branch, star and ring architectures and both IO and peer-to-peer communications are possible.
Like office networks, PROFINET uses Ethernet switches to connect devices. PROFINET switches can be external infrastructure components or integrated switches. In general, the only requirement for Ethernet switches in a PROFINET network is 100 Mbps full duplex transmission. Most Commercial Off-The-Shelf (COTS) switches can work in a PROFINET network. However, there are many factors to consider when selecting a device, such as the installation environment (harsh manufacturing environments) and requirements for specific PROFINET features. The following section on Selecting will give further details.
In addition, specialized ASIC-based switches are now being fitted into many end devices. Both 2 and 4 port versions are available. Onboard 2-port switches allow easy ‘daisy-chaining’ of devices to enable bus-like line networks to be created. Design considerations here include taking into account accumulated switching delays. In linear networks, 10 switches in a line are usually the desirable maximum.
If HMI traffic and data-intensive signals (e.g. vision) are required, it’s worth paying attention to overall bandwidth requirements. PROFINET’s ability to reserve bandwidth for particular functions means that limitations rarely occur. It also means that multiple-functionality can exist on a single network.
For high integrity systems, PROFINET supports media redundancy with ring topologies. If a cable or device fails, then the system automatically segments itself into a ‘line’ topology to keep the rest of the system active.
Learn all about PROFINET design Here:
§3.2 – Selecting
To ensure the highest quality performance and to guarantee interoperability it is a mandatory requirement that all PROFINET products are certified. Only in that way users can have full confidence in their purchases. A list of products can be found in the Product Finder on the main PI website; NOTE: it is the responsibility of the manufacturer to maintain the listing of their products there! If a product cannot be found as such, it does not necessarily mean the product has not been certified. Check with the device manufacturer for a certificate.
For infrastructure devices such as switches, COTS (Commercial Off-The-Shelf) can be utilized. However, here is a list of the parameters that are important (and not important!) to PROFINET to guide you in making the right choice:
Used in PROFINET?
Managed vs. Unmanaged
Managed switches offer
Both can be used
Quality of Service (QoS)
Prioritize frames according
Isolates traffic in different network sections
Helps to monitor the traffic of a device
Reduces Multicast flooding*
Not needed by PROFINET
(*Why is Multicast an issue? Multicast is a default Ethernet mechanism used by some Industrial Ethernet protocols. It distributes every message to multiple receivers. This can quickly lead to ‘flooding’ of the network … and not just the automation network either as it will jeopardize the performance of any connected office Ethernet too! Therefore, in an Industrial Ethernet based on multicast messaging, all switches have to support a special feature called ‘IGMP Snooping’ which monitors what is happening and takes appropriate action to prevent ‘flooding’. This adds to costs. PROFINET uses only unicast messages and is not troubled by the requirement.)
Learn more about PROFINET switches: Managed vs Unmanaged
§3.3 – Installing
Standard ‘best practice’ in cable installation and maintenance should be followed at all times. Here are a few installation tips that should be borne in mind:
- Remember that the environment you are planning for may be dirty, dusty, electrically noisy and generally unfriendly to data transmissions and infrastructure components of all types.
- Normal twisted pair cabling is suitable for PROFINET. TCP/IP has methods in place to resend telegrams when lost but the timing is not acceptable for industrial use! In other words, electrically noisy environments can easily interrupt your data flows and may cause control malfunctions. In these situations, always use Shielded Twisted Pair cabling.
- Grounding at both ends is best. However, it’s not always applicable due to ground loops.
- The need for shielding is independent of the protocol used. All Industrial Ethernets – and indeed fieldbuses – need protection in noisy environments. If you used shielded cable with DeviceNet or PROFIBUS, use shielded cable with PROFINET as well.
- Use PROFINET-rated cable.
- Always use rugged connectors too. Field installable RJ-45 types are available, as illustrated.
Read this installation guidelines before starting your project:
§3.4 – Commissioning
There are many resources that you can call on to help with commissioning…
- A PROFINET Commissioning Guideline is available, together with a separate Word file, which provides protocols and checklists for individual adaptations. The commissioning guideline explains setting IP addresses, PROFINET device names and typical steps to configure real time IO devices with their GSD files, and proper network measurements.
- Excellent engineering and test tools designed for use with Industrial Ethernet in general – and PROFINET in particular – are available from many sources. Such tools can investigate full Ethernet and PROFINET activity, provide a detailed analysis of parameters such as delays and jitter, and time stamp frames for later assessment.
- General-purpose Ethernet tools include the Wireshark software analyzer which uses the Ethernet ports on a PC as the analyzer hardware. Wireshark is license free and acts as a sniffer to analyze the Ethernet traffic.
Read the commisioning guideline Here:
§3.5 – Maintaining
Standard Ethernet has a set of diagnostic tools and protocols that will be familiar to office-based technical personnel. These can be utilized in the industrial environment to provide detailed information about lower-level transport-oriented issues such as TCP, UDP and IP activity. They can also support statistical and connection analysis.
Standard Ethernet protocol tools
The use of familiar Ethernet protocols means that browser based access to individual devices is possible from any PC in any location – even over the internet. Many PROFINET devices incorporate a web server for this purpose. A browser can also read out information such as device status and configure a device either locally or from a remote site.
IT protocols familiar from the industrial world include SNMP (for managing components such as switches and reading statistics and diagnostics). Again these can be used from anywhere in the network. Another familiar protocol is LLDP which is used for mapping network topologies for making device replacement easy.
The PROFINET specifications also include a set of specific diagnostic tools which operate at the application layer level. These provide more advanced diagnostics capabilities in standardized formats. Some allow for remote monitoring of networks, and some are intended for on-site use.
Simple Device Replacement
Many devices can be replaced in the field without the need for configuration – no computer is required; you just take the new device out of the box and install it in place of a failed unit.
More on network diagnostics and monitoring tools Here:
§4.0 – Migrating from PROFIBUS
If you have PROFIBUS networks already installed, or if you’ve got PROFIBUS skills available in your plant then migrating from PROFIBUS to PROFINET will be quick and simple. That’s because the Working Groups which developed PROFINET drew heavily on the experience of PROFIBUS. For example, if you’re familiar with GSD files for engineering you’ll be familiar with the GSDML files used by PROFINET. Likewise, the diagnostic functions. Also, many of the PROFIBUS profiles – for example, PROFIsafe and PROFIdrive – will also be familiar.
The migration process to PROFINET was made simple not only for PROFIBUS but also from many other existing protocols. PROFINET achieves this through the use of the unique ‘proxy’ concept, which is covered in detail in this section. Proxies are part of the PROFINET specification and perform consistently across all protocols. PROFINET proxies are defined for the following protocols:
- PROFIBUS DP
- PROFIBUS PA
- Foundation Fieldbus
PROFINET is alone in being able to integrate many popular fieldbuses, making it the ideal way to move to Industrial Ethernet architectures.
Special Note: In addition to the proxy migration option, a wide range of gateway devices exists for connecting legacy protocols to PROFINET from various vendors.
Read more on PROFIBUS to PROFINET migration:
§4.1 – The Proxy Concept
A PROFINET ‘proxy’ is a black-box interface sitting between PROFINET and a sub-network such as PROFIBUS. It differs from a conventional gateway device in that it maps the underlying protocol to PROFINET. This allows a controller on the PROFINET network to access devices on the sub-network with ease because all functions and services are directly available without further interpretation.
With proxies, investments in the skills, equipment, and software associated with the sub-network can be retained. No changes to automation systems at the fieldbus level are required; fieldbus networks can simply be connected into the PROFINET architecture and utilized as before. Therefore, PROFINET can greatly assist in the expansion and deployment of distributed automation architectures. It also simplifies greater vertical integration, moving manufacturing closer to enterprise IT networks.
PROFINET is also highly scalable and modular in concept, not every feature needs to be deployed at once. New users can start simple and build as required. Migration can happen in steps, allowing plant and personnel to build experience while improving productivity and profitability.
§4.2 – Proxy Devices
Remember, a ‘proxy’ is a special interface for connecting PROFINET to lower level networks such as PROFIBUS, INTERBUS, etc. A proxy differs from a standard gateway or bridge in that acts as a sub-network master and a PROFINET slave simultaneously. The underlying protocol is therefore mapped directly to PROFINET and the PROFINET controller ‘sees’ the sub-network as remote IO. Proxies are part of the PROFINET specification.
Company: Phoenix Contact; Product: FL NP PND-4TX IB(-LK)
Description: A proxy for seamless and uniform connection of field devices on an INTERBUS network to PROFINET IO. Offers convenient configuration and automatic IP addressing or device-naming via a PROFINET IO controller. Also cgives optimized time behavior since process data is grouped in an efficient manner. Status and diagnostics are provided via a two-figure seven-segment display and additional LEDs.
Company: Comsoft; Product: FNL Proxy PN/PB
This 24 Volt hat rail module contains one PROFIBUS DP interface, four PROFINET IO RT interfaces and one RS232 service interface for commissioning and diagnostics. The proxy integrates both existing and new PROFIBUS DP devices without any modification or adaptation into a PROFINET IO network. It implements a range of PROFIBUS diagnostic functions as well as offering additional features such as a configurable PROFIBUS DP Master in case of a breakdown of the PROFINET IO network and the detailed indication of error codes.
Company: Hilscher; Product: NetLINK
Description: netLINK is a proxy for integrating a PROFIBUS-DP slave into a PROFINET network. It is housed in a standard bus connector format and can be directly mounted on the target equipment. It is either powered via its front connector or with 24 V over an additional terminal. Variants for different applications are available. netLINK is an elegant alternative to today’s available DIN-rail mountable gateways or equivalent rack based systems.
Company: Beckhoff: Product: EK9300
Description: The EK9300 Bus Coupler permits the simple connection of high-performance EtherCAT devices to PROFINET networks.The EK9300 Bus Coupler acts as a PROFINET RT device and integrates a simple EtherCAT master, which connects the EtherCAT Terminals by auto-configuration. One station consists of an EK9300 and any number of EtherCAT Terminals.
Company: Phoenix Contact; Product: FL NP PND-4TX PB
Description: A proxy for seamless and uniform connection of field devices on a PROFIBUS network to PROFINET IO. Offers convenient configuration and automatic IP addressing/device naming via a PROFINET IO controller. Also cgives optimized time behavior since process data is grouped in an efficient manner. Status and diagnostics are provided via a two-figure seven-segment display and additional LEDs.
Company: Siemens; Product: IE/PB Link PN10
Description: Vertical integration of PROFIBUS-based devices into Industrial Ethernet and PROFINET. Transfers the data from the PROFIBUS field devices to Industrial Ethernet/PROFINET and integrates the PROFIBUS devices into a PROFINET-based automation solution. Also, enables configuration of the PROFIBUS devices on an Ethernet-based engineering workstation.
Company: Siemens; Product: IWLAN/PB Link PN10
Description: PN10 is a PROFINET IO proxy which connects PROFIBUS DP slaves to PROFINET IO controllers to provide a link between Industrial Wireless LAN and PROFIBUS. It realizes the flexible integration of field level systems into an IWLAN radio infrastructure according to IEEE 802.11b/g and IEEE 802.11a using SCALANCE W Access Points.
Proxy specifications also exist for DeviceNet.
§4.3 – Migrating to PROFINET
Many of the design, engineering and deployment issues for PROFINET resemble those of PROFIBUS. However, PROFINET offers additional capabilities.
- Simple device replacement: Just physically replace a device when it fails. There are no switches to set and no computer is needed.
- Device names: Meaningful names can be allocated by the user which contributes to much simpler replacement procedures. The PLC assigns an IP address to the node.
- Standard wireless: Familiar WLAN and Bluetooth protocols are used.
- More topology options: Ethernet offers many more topology options, including star, ring and tree structures which make it easier to design and commission according to the layout and functions of a plant, especially where redundancy, long distance, and remote connections are needed.
- Shared Device/i-Device: One device can be accessed by more than one controller. This flexible assignment of modules to different controllers suits many applications, for example, a single sensor that participates in a safety function and needs to communicate with a failsafe PLC. An IO-controller can also operate in a so-called i-Device mode, in which it combines the IO-Device functionality with an IO-Controller function on the same interface (see diagram).
Much more about PROFINET in this short webinar:
§4.4 – PROFINET Features vs. PROFIBUS
PROFINET offers much higher performance than PROFIBUS and other fieldbuses in terms of:
- Unlimited scalability
- Unlimited address space
- Larger message size (1440 bytes vs. 244)
- Machine 2 Machine (M2M) communication
- Vertical integration capabilities
- The possibility to coordinates more drive axes (32 axes vs. >150) – with IRT updates in 1 ms range, with less than 1 us jitter
- It’s faster too, which means more application potential and fewer interfaces
Much more on the PROFINET vs PROFIBUS comparison:
§5.1 – Consultation
PROFINET has core functionality that defines how data is transferred within a network. This relies on basic Ethernet standards such as TCP, UDP, DHCP, SNMP, LLDP, IP, and MRP. To this core functionality are added a set of options which deliver the full Industrial Ethernet experience. The basic industrial automation services are TCP/UDP IP, for general data transfer; PROFINET real time (RT) for a broad range of IO applications including drives; and PROFINET isochronous real time (IRT), for advanced motion control.
The precise combination of functions used is up to the designer/developer and this provides considerable flexibility in device or system supply. PI & member organizations offer support and consultation:
- Seminars, Workshops, Certification Classes
- Development Packages for PROFINET Field Devices and Controllers
- Fundamentals, Engineering, and Support
- Worldwide and local service from PI
- Test Labs can give upfront guidance about the mandatory certification processes
For Certified and Free training in your area:
§5.2 – Device Type
A PROFINET network is composed of different types of components. Each component performs different tasks, generally, they are described in four node classes.
- IO Devices: Input/Output devices are controlled by the IO Controller. Examples include actuators, sensors, drives/motors, switches, solenoid & pneumatic valves, robots, protection & safety technology, and encoders.
- IO Controller: Controllers retrieve and process data from components or write to IO devices. These can be PLCs or PACs.
- IO Supervisor: Supervisors will initiate parametrization or programming. They will typically read from, or write to, other IO devices and IO controllers on the network and integrate information vertically through the network.
- Network Components: Switches or access points for wireless communication are a few examples of network components. Some network components can also be operated simultaneously as IO devices for enhanced network diagnostics.
Some PROFINET devices offer multifunction capability and can support more than one node class.
- Types of Interfaces – Options include: Copper wire (Ethernet cable for 100 Mbits/s, full duplex), Fiber Optics (FO), or Wireless (e.g. WLAN, Bluetooth)
- Number of Interfaces – Single Port or Multi Port
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§5.3 – Device Functionality
After determining the node class of the device, it is important to know where the device will be deployed so that it can effectively communicate with the necessary speed.
- TCP/IP and/or UDP/IP is used for configuration or parameter assignment. It is a slightly slower type of communication, but because of its availability in PROFINET, this allows for simple vertical integration into MES/ERP systems.
RT – Real Time
- Real time transmission can be used in almost every node class; but will be employed most by devices used generally in factory automation. Typically these components update every 1 – 8 milliseconds.
IRT – Isochronous Real Time
- IRT data transmission is high-speed, high-performance, and deterministic. Examples include motion control applications with update times of less than 1 millisecond.
Furthermore, each communication class is part of a broader categorization of PROFINET devices. These Conformance Classes incorporate other features, and manufacturers will define which functions will be supported by their device. Then, the component is classified to help simplify its selection prior to usage, guarantee its properties, and ensure interoperability.
Watch this webinar for much more on conformance classes and development:
§5.4 – Device Options
Incorporating PROFINET into your device means modularity and flexibility. Start simple and add functionality as required. There are features that some manufacturers will desire to be integrated, and others will not. Some examples of these optional modules include:
- Fast Startup (FSU): IO Devices go instantly into a ‘power on’ state in response to signals from an IO Controller.
- Network Redundancy: Redundancy configuration with ring topologies for high availability systems.
- PROFIsafe: Application Profile for the implementation of functional safety with less effort, cabling, and maintenance. Further information can be found under the PROFIsafe section.
- PROFIenergy: Application Profile developed to save energy and reduce utility bills; it is built on top of the existing PROFINET protocol. PROFIenergy is discussed in depth in the Features section.
§5.5 – Development Environment
When choosing the format by which PROFINET will be integrated into a device, it is mainly dependent upon the eventual goals and applications of the component. Different solutions exist for this; broadly they are:
|FPGA (Field Programmable Gate Array) + Software Stack||The FPGA is based on the chosen operating system, then it is supplemented by a supplier supported PROFINET stack.||
|Standard Microcontroller (MCU)||Add PROFINET to an existing MCU for “Ethernet on a chip” and deploy your own PROFINET stack.||
|Certified Boards & Modules||This is hardware that is supplied by PROFINET embedded vendors for integration into devices.||
|ASIC (Application Specific Integrated Circuit)||ASICs are chips with full functionality built into and designed specifically for PROFINET usage.||
|External Coupler||An external coupler has the PROFINET interface implemented which is then connected in series.||
Many of these products are supported with SDKs (software development kits). With each option, there are multiple choices for consultation and engineering support, through vendors themselves and through the global PI Competence Center network.
§5.6 – Development Functionality
Not all development environments are capable of handling every conformance class. Certain devices will require hardware and software that will enable it to perform in its desired application. For example, the requirements of conformance class C mean that devices have a multi-port interface:
§5.7 – Hardware / Software Design
Hardware and software design can pose special challenges and if you do not have in-house resources, you may need to find a supplier to help. A modular solution may well suit your needs if numbers are small. Flexibility is an additional benefit in these circumstances. Maybe your volumes justify a special board design, or custom product. The advantage of collaborating with an external technology or development partner when developing a PROFINET interface is that the device manufacturer can concentrate on its core areas of expertise.
§5.8 – Certification Test
Conformance testing and certification are mandatory for all PROFINET devices to guarantee interoperability. It is also the primary factor influencing customers to buy PROFINET products.
Prior to the certification test, a vendor ID must first be issued by PI (contact PI North America for help). It is recommended that a system test is performed with PROFINET tools such as a PLC or ProfinetCommander before going into testing. Certification is undertaken by an accredited PI test lab and is carried out in accordance with established and proven procedures. The PI Lab for North America is the PROFI Interface Center, which offers device testing and further information on their website. Simultaneously, CE and/or UL certification is necessary and should be carried out independently.
The test lab tests for compliance with the PROFINET specification and any profiles involved, and also for interoperability with other PROFINET devices. Only when all test procedures are successfully undertaken will PI issue a formal certificate for the device. Accredited PI test labs are qualified to help mainly to certify devices but may also be able to advise on design issues and recommend adjustments to help ensure successful certification.
§5.9 – Release Product
Once your device is certified, it is now ready for the market. Make sure your package is complete, including sales literature and web presence. Also, make sure your sales force thoroughly understands the product. GSD files should be included in your package, or preferably made available over the internet.
You may have your own routes to market, but PI can help you:
- A member-maintained on-line product database at www.profibus.com
- Electronic newsletters such as PROFINEWS with large distribution lists which can be used to promote your product and generate sales leads
- Feature member press releases in the PI North America website
These services are free to members. Your local Regional PI Association office (that’s PI North America in North America) will also be able to help by offering the chance to advertise and to exhibit at regional events. The advertising and exhibiting opportunities in North America are detailed here. Most of these are excellent ways to meet new customers and to network with like-minded PROFINET people.