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Wikipedia

Profinet

Profinet (usually styled as PROFINET, as a portmanteau for Process Field Network) is an industry technical standard for data communication over Industrial Ethernet, designed for collecting data from, and controlling equipment in industrial systems, with a particular strength in delivering data under tight time constraints. The standard is maintained and supported by Profibus and Profinet International, an umbrella organization headquartered in Karlsruhe, Germany.

Profinet
Communication protocol
PurposeReal-time Ethernet for industrial Automation
Developer(s)PROFIBUS & PROFINET International
Introduction2003; 20 years ago (2003)
Based onEthernet, Profibus
OSI layerApplication layer
RFC(s)IEC 61784-2, IEC 61158

Functionalities

Overview

Profinet implements the interfacing to peripherals.[1][2] It defines the communication with field connected peripheral devices. Its basis is a cascading real-time concept. Profinet defines the entire data exchange between controllers (called "IO-Controllers") and the devices (called "IO-Devices"), as well as parameter setting and diagnosis. IO-Controllers are typically a PLC, DCS, or IPC; whereas IO-Devices can be varied: I/O blocks, drives, sensors, or actuators. The Profinet protocol is designed for the fast data exchange between Ethernet-based field devices and follows the provider-consumer model.[1] Field devices in a subordinate Profibus line can be integrated in the Profinet system seamlessly via an IO-Proxy (representative of a subordinate bus system).

Conformance Classes (CC)

Applications with Profinet can be divided according to the international standard IEC 61784-2 into four conformance classes:

  • Conformance Class B (CC-B) stipulates that the network infrastructure also includes certified products and is structured according to the guidelines of Profinet. Shielded cables increase robustness and switches with management functions facilitate network diagnostics and allow the network topology to be captured as desired for controlling a production line or machine. Process automation requires increased availability, which can be achieved through media and system redundancy. For a device to adhere to Conformance Class B, it must communicate successfully via Profinet, have two ports (integrated switch), and support SNMP.
  • With Conformance Class C (CC-C), positioning systems can be implemented with additional bandwidth reservation and application synchronization. Conformance Class C devices additionally communicate via Profinet IRT.
  • For Conformance Class D (CC-D), Profinet is used via Time-Sensitive Networking (TSN). The same functions can be achieved as with CC-C. In contrast to CC-A and CC-B, the complete communication (cyclic and acyclic) between controller and device takes place on Ethernet layer 2. The Remote Service Interface (RSI) was introduced for this purpose.
Functionalities of Profinet Conformance Classes
Functionality Class A (CC-A) Class B (CC-B) Class C (CC-C) Class D (CC-D)
Basic functionality
  • RT-Communication
  • Cyclic I/O
  • Parameter
  • Alarms
  • RT-Communication
  • Cyclic I/O
  • Parameter
  • Alarms
  • Network diagnostics
  • Topology detection
  • System redundancy
  • RT-Communication
  • Cyclic I/O
  • Parameter
  • Alarms
  • Network diagnostics
  • Topology detection
  • Bandwidth reservation (IRT)
  • Synchronisation
  • Seamless media redundancy
  • RT-Communication
  • Cyclic I/O
  • Parameter
  • Alarms
  • Network diagnostics
  • Topology detection
  • Bandwidth reservation (TSN)
  • Synchronisation
  • System redundancy
  • Seamless media redundancy
Certification
  • Controller
  • Devices
  • Controller
  • Devices
  • Network components
  • Controller
  • Devices
  • Network components
  • Controller
  • Devices
  • Network components
Cabling

IEC 61784-5-3 and IEC 24702:

  • Copper
  • Fibre optics
  • Wireless

IEC 61784-5-3:

  • Copper
  • Fibre optics

IEC 61784-5-3:

  • Copper
  • Fibre optics

IEC 61784-5-3:

  • Copper
  • Fibre optics
Typical application
  • Universal

Device types

A Profinet system consists of the following devices:[1]: 3 

  • The IO-Controller, which controls the automation task.
  • The IO-Device, which is a field device, monitored and controlled by an IO-Controller. An IO-Device may consist of several modules and sub-modules.
  • The IO-Supervisor is software typically based on a PC for setting parameters and diagnosing individual IO-Devices.

System structure

A minimal Profinet IO-System consists of at least one IO-Controller that controls one or more IO-Devices. In addition, one or more IO-Supervisors can optionally be switched on temporarily for the engineering of the IO-Devices if required.

If two IO-Systems are in the same IP network, the IO-Controllers can also share an input signal as shared input, in which they have read access to the same submodule in an IO-Device.[1]: 3 [2] This simplifies the combination of a PLC with a separate safety controller or motion control. Likewise, an entire IO-Device can be shared as a shared device,[1]: 11  in which individual submodules of an IO-Device are assigned to different IO-Controllers.

Each automation device with an Ethernet interface can simultaneously fulfill the functionality of an IO-Controller and an IO-Device. If a controller for a partner controller acts as an IO-Device and simultaneously controls its periphery as an IO-Controller, the tasks between controllers can be coordinated without additional devices.

Relations

An Application Relation (AR) is established between an IO-Controller and an IO-Device. These ARs are used to define Communication Relations (CR) with different characteristics for the transfer of parameters, cyclic exchange of data and handling of alarms.[1]: 4 

Engineering

The project engineering[1]: 5  [2] of an IO system is nearly identical to the Profibus in terms of "look and feel":

  • The properties of an IO-Device are described by the device manufacturer in a GSD file (General Station Description). The language used for this is GSDML (GSD Markup Language) - an XML-based language. The GSD file serves an engineering environment as a basis for planning the configuration of a Profinet IO system.
  • All Profinet field devices determine their neighbors.[1]: 8  This means that field devices can be exchanged in the event of a fault without additional tools and prior knowledge. By reading out this information, the plant topology can be displayed graphically for better clarity.
  • The engineering can be supported by tools such as PROFINET Commander[3] or PRONETA.[4]

Dependability

Profinet is also increasingly being used in critical applications. There is always a risk that the required functions cannot be fulfilled. This risk can be reduced by specific measures as identified by a dependability[5] analyses. The following objectives are in the foreground:

  1. Safety: Ensuring functional safety. The system should go into a safe state in the event of a fault.
  2. Availability: Increasing the availability. In the event of a fault, the system should still be able to perform the minimum required function.
  3. Security: Information security is to ensure the integrity of the system.

These goals can interfere with or complement each other.

Functional safety: Profisafe

Profisafe[6] defines how safety-related devices (emergency stop buttons, light grids, overfill prevention devices, ...) communicate with safety controllers via Profinet in such a safe way that they can be used in safety-related automation tasks up to Safety Integrity Level 3 (SIL) according to IEC 61508, Performance Level "e" (PL) according to ISO 13849, or Category 4 according to EN 954-1.

Profisafe implements safe communication via a profile,[7] i.e. via a special format of the user data and a special protocol. It is designed as a separate layer on top of the fieldbus application layer to reduce the probability of data transmission errors. The Profisafe messages use standard fieldbus cables and messages. They do not depend on error detection mechanisms of underlying transmission channels, and thus supports securing of whole communication paths, including backplanes inside controllers or remote I/O. The Profisafe protocol uses error and failure detection mechanisms such as:

and is defined in the IEC 61784-3-3 standard.

Increased availability

High availability[8] is one of the most important requirements in industrial automation, both in factory and process automation. The availability of an automation system can be increased by adding redundancy for critical elements. A distinction can be made between system and media redundancy.

System redundancy

System redundancy can also be implemented with Profinet to increase availability. In this case, two IO-Controllers that control the same IO-Device are configured. The active IO-Controller marks its output data as primary. Output data that is not marked is ignored by an IO-Device in a redundant IO-System. In the event of an error, the second IO-Controller can therefore take control of all IO-Devices without interruption by marking its output data as primary. How the two IO-Controllers synchronize their tasks is not defined in Profinet and is implemented differently by the various manufacturers offering redundant control systems.

Media redundancy

Profinet offers two media redundancy solutions. The Media Redundancy Protocol (MRP) allows the creation of a protocol-independent ring topology with a switching time of less than 50 ms. This is often sufficient for standard real-time communication with Profinet. To switch over the redundancy in the event of an error without time delay, the "Media Redundancy for Planned Duplication" (MRPD) must be used as a seamless media redundancy concept. In the MRPD, the cyclic real-time data is transmitted in both directions in the ring-shaped topology. A time stamp in the data packet allows the receiver to remove the redundant duplicates.

Security

The IT security concept[9] for Profinet assumes a defense-in-depth[10] approach. In this approach, the production plant is protected against attacks, particularly from outside, by a multi-level perimeter, including firewalls. In addition, further protection is possible within the plant by dividing it into zones using firewalls. In addition, a security component test ensures that the Profinet components are resistant to overload to a defined extent.[11] This concept is supported by organizational measures in the production plant within the framework of a security management system according to ISO 27001.

Application Profiles

For a smooth interaction of the devices involved in an automation solution, they must correspond in their basic functions and services. Standardization is achieved by "profiles"[12] with binding specifications for functions and services. The possible functions of communication with Profinet are restricted and additional specifications regarding the function of the field device are prescribed. These can be cross-device class properties such as a safety-relevant behavior (Common Application Profiles) or device class specific properties (Specific Application Profiles).[13] A distinction is made between

  • Device profiles for e.g. robots, drives (PROFIdrive), process devices, encoders, pumps
  • Industry Profiles for e.g. laboratory technology or rail vehicles
  • Integration Profiles for the integration of subsystems such as IO-Link systems

Drives

PROFIdrive[14] is the modular device profile for drive devices. It was jointly developed by manufacturers and users in the 1990s and since then, in conjunction with Profibus and, from version 4.0, also with Profinet, it has covered the entire range from the simplest to the most demanding drive solutions.

Energy

Another profile is PROFIenergy which includes services for real time monitoring of energy demand. This was requested in 2009 by the AIDA group of German automotive Manufacturers (Audi, BMW, Mercedes-Benz, Porsche and Volkswagen ) who wished to have a standardised way of actively managing energy usage in their plants. High energy devices and sub-systems such as robots, lasers and even paint lines are the target for this profile, which will help reduce a plant's energy costs by intelligently switching the devices into 'sleep' modes to take account of production breaks, both foreseen (e.g. weekends and shut-downs) and unforeseen (e.g. breakdowns).

Process automation

Modern process devices have their own intelligence and can take over part of the information processing or the overall functionality in automation systems. For integration into a Profinet system,[15][16] a two-wire Ethernet is required in addition to increased availability.

Process devices

The profile PA Devices [17] defines for different classes of process devices all functions and parameters typically used in process devices for the signal flow from the sensor signal from the process to the pre-processed process value, which is read out to the control system together with a measured value status. The PA Devices profile contains device data sheets for

  1. Pressure and differential pressure
  2. Level, temperature and flow rate
  3. Analog and digital inputs and outputs
  4. Valves and actuators
  5. Analysis equipment

Advanced Physical Layer

Ethernet Advanced Physical Layer (Ethernet-APL)[18] describes a physical layer for the Ethernet communication technology which is especially developed for the requirements of the process industries. The development of Ethernet-APL was determined by the need for communication at high speeds and over long distances, the supply of power and communications signals via common single, twisted-pair (2-wire) cable as well as protective measures for the safe use within explosion hazardous areas. Ethernet APL opens the possibility for Profinet to be incorporated into process instruments.

Technology

Profinet protocols

Profinet uses the following protocols in the different layers[2]: 15  of the OSI model:

OSI-Layer Profinet
7a Application Fieldbus Application Layer (FAL)
Services and protocols
OPC UA
7b RSI empty empty RPC --
6 Presentation --
5 Session
4 Transport UDP TCP
3 Network IP
2 Data Link TSN CSMA/CD
1 Physical Ethernet

Layers 1-2: Mainly full-duplex with 100 MBit/s electrical (100BASE-TX) or optical (100BASE-FX) according to IEEE 802.3 are recommended[19] as device connections. Autocrossover is mandatory for all connections so that the use of crossover cables can be avoided. From IEEE 802.1Q the VLAN with priority tagging is used. All real-time data are thus given the highest possible priority 6 and are therefore forwarded by a switch with a minimum delay.

The Profinet protocol can be recorded and displayed with any Ethernet analysis tool. Wireshark is capable of decoding Profinet telegrams.

The Link Layer Discovery Protocol (LLDP) has been extended with additional parameters, so that in addition to the detection of neighbors, the propagation time of the signals on the connection lines can be communicated.

Layers 3-6: Either the Remote Service Interface (RSI) protocol or the Remote Procedure Call (RPC) protocol is used for the connection setup and the acyclic services. The RPC protocol is used via User Datagram Protocol (UDP) and Internet Protocol (IP) with the use of IP addresses. The Address Resolution Protocol (ARP) is extended for this purpose with the detection of duplicate IP addresses. The Discovery and basic Configuration Protocol (DCP) is mandatory for the assignment of IP addresses. Optionally, the Dynamic Host Configuration Protocol (DHCP) can also be used for this purpose. No IP addresses are used with the RSI protocol. Thus, IP can be used in the operating system of the field device for other protocols such as OPC Unified Architecture (OPC UA).

Layer 7: Various protocols[1] are defined to access the services of the Fieldbus Application Layer (FAL). The RT (Real-Time) protocol for class A & B applications with cycle times in the range of 1 - 10 ms. The IRT (Isochronous Real-Time) protocol for application class C allows cycle times below 1 ms for drive technology applications. This can also be achieved with the same services via Time-Sensitive Networking (TSN).

Technology of Conformance Classes

The functionalities of Profinet IO are realized with different technologies and protocols:

Technology and protocols of Profinet Conformance Classes
Functionality Technology/Protocol CC-A CC-B CC-C CC-D
Cyclic data exchange
Acyclic parameter data
Device diagnostics, alarms
Device identification
Topology information
RT
Read/Write Record
Alarm Handling
I&M 0
LLDP
mandatory mandatory mandatory mandatory
Multiple access to inputs
Split device functions to controllers
Extended device identification
Shared Input
Shared Device
I&M 1-4
optional optional optional optional
Network diagnostics
Port related statistics
SNMP
PDEV
- mandatory mandatory Mandatory
System redundancy 2 controllers - mandatory for process automation optional optional
Automatic addressing
Configuration change during operation
Time stamping of process data
Media redundancy
Fast restart
LLDP, DCP
DR
IEC 61588
MRP
FSU
- optional optional optional
Bandwidth reservation > 250 μs cycle time IRT - - mandatory -
Bandwidth reservation < 250 μs Cycle time
Clock synchronicity
Optimized operating mode
Media redundancy without latency
IRT
IRT, PTP
DFP
MRPD
- - optional -
Bandwidth reservation
Clock synchronicity at 100MB
Optimized operating mode
TSN
TAS
Frame Preemption
- - - mandatory

Technology of Class A (CC-A)

The basic function of the Profinet is the cyclic data exchange between the IO-Controller as producer and several IO-Devices as consumers of the output data and the IO-Devices as producers and the IO-Controller as consumer of the input data.[1] Each communication relationship IO data CR between the IO-Controller and an IO-Device defines the number of data and the cycle times.

All Profinet IO-Devices must support device diagnostics and the safe transmission of alarms via the communication relation for alarms Alarm CR.

In addition, device parameters can be read and written with each Profinet device via the acyclic communication relation Record Data CR. The data set for the unique identification of an IO-Device, the Identification and Maintenance Data Set 0 (I&M 0), must be installed by all Profinet IO-Devices. Optionally, further information can be stored in a standardized format as I&M 1-4.

For real-time data (cyclic data and alarms), the Profinet Real-Time (RT) telegrams are transmitted directly via Ethernet. UDP/IP is used for the transmission of acyclic data.

Management of the Application Relations (AR)

The Application Relation (AR) is established between an IO-Controller and every IO-Device to be controlled. Inside the ARs are defined the required CRs. The Profinet AR life-cycle consists of address resolution, connection establishment, parameterization, process IO data exchange / alarm handling, and termination.

  1. Address resolution: A Profinet IO-Device is identified on the Profinet network by its station name.[note 1] Connection establishment, parameterization and alarm handling are implemented with User Datagram Protocol (UDP), which requires that the device also be assigned an IP address. After identifying the device by its station name, the IO-Controller assigns the pre-configured IP address to the device.
  2. Connection establishment: Connection establishment starts with the IO-Controller sending a connect request to the IO-Device. The connect request establishes an Application Relationship (AR) containing a number of Communication Relationships (CRs) between the IO-Controller and IO-Device.[2] In addition to the AR and CRs, the connect request specifies the modular configuration of the IO-Device, the layout of the process IO data frames, the cyclic rate of IO data exchange and the watchdog. Acknowledgement of the connect request by the IO-Device allows parameterization to follow. From this point forward, both the IO-Device and IO-Controller start exchanging cyclic process I/O data frames. The process I/O data frames don't contain valid data at this point, but they start serving as keep-alive to keep the watchdog from expiring.
  3. Parameterization: The IO-Controller writes parameterization data to each IO-Device sub-module in accordance with the General Station Description Mark-up Language (GSDML) file. Once all sub-modules have been configured, the IO-Controller signals that parameterization has ended. The IO-Device responds by signaling application readiness, which allows process IO data exchange and alarm handling to ensue.[2]
  4. Process IO data exchange / alarm handling: The IO-Device followed by the IO-Controller start to cyclically refresh valid process I/O data. The IO-Controller processes the inputs and controls the outputs of the IO-Device.[2] Alarm notifications are exchanged acyclically between the IO-Controller and IO-Device as events and faults occur.[1]
  5. Termination: The connection between the IO-Device and IO-Controller terminates when the watchdog expires.[2] Watchdog expiry is the result of a failure to refresh cyclic process I/O data by the IO-Controller or the IO-Device.[1] Unless the connection was intentionally terminated at the IO-Controller, the IO-Controller will try to restart the Profinet Application Relation.

Technology of Class B (CC-B)

In addition to the basic Class A functions, Class B devices must support additional functionalities.[1] These functionalities primarily support the commissioning, operation and maintenance of a Profinet IO system and are intended to increase the availability of the Profinet IO system.

Support of network diagnostics with the Simple Network Management Protocol (SNMP) is mandatory. Likewise, the Link Layer Discovery Protocol (LLDP) for neighborhood detection including the extensions for Profinet must be supported by all Class B devices. This also includes the collection and provision of Ethernet port-related statistics for network maintenance. With these mechanisms, the topology of a Profinet IO network can be read out at any time and the status of the individual connections can be monitored. If the network topology is known, automatic addressing of the nodes can be activated by their position in the topology. This considerably simplifies device replacement during maintenance, since no more settings need to be made.

High availability of the IO system is particularly important for applications in process automation and process engineering. For this reason, special procedures have been defined for Class B devices with the existing relationships and protocols. This allows system redundancy with two IO-Controllers accessing the same IO-Devices simultaneously. In addition, there is a prescribed procedure Dynamic Reconfiguration (DR), how the configuration of an IO-Device can be changed with the help of these redundant relationships without losing control over the IO-Device.

Technology of Class C (CC-C)

For the functionalities of Conformance Class C (CC-C) the Isochronous Real-Time[1] (IRT) protocol is mainly used.

With the bandwidth reservation, a part of the available transmission bandwidth of 100 MBit/s is reserved exclusively for real-time tasks. A procedure similar to a time multiplexing method is used. The bandwidth is divided into fixed cycle times, which in turn are divided into phases. The red phase is reserved exclusively for class C real-time data, in the orange phase the time-critical messages are transmitted and in the green phase the other Ethernet messages are transparently passed through. To ensure that maximum Ethernet telegrams can still be passed through transparently, the green phase must be at least 125 μs long. Thus, cycle times under 250 μs are not possible in combination with unchanged Ethernet.

In order to achieve shorter cycle times down to 31.25 μs, the Ethernet telegrams of the green phase are optionally broken down into fragments. These short fragments are now transmitted via the green phase. This fragmentation mechanism is transparent to the other participants on the Ethernet and therefore not recognizable.

In order to implement these bus cycles for bandwidth reservation, precise clock synchronization of all participating devices including the switches is required with a maximum deviation of 1 μs. This clock synchronization is implemented with the Precision Time Protocol (PTP) according to the IEEE 1588-2008 (1588 V2) standard. All devices involved in the bandwidth reservation must therefore be in the same time domain.

For position control applications for several axes or for positioning processes according to the PROFIdrive[14] drive profile of application classes 4 - 6, not only must communication be timely, but the actions of the various drives on a Profinet must also be coordinated and synchronized. The clock synchronization of the application program to the bus cycle allows control functions to be implemented that are executed synchronously on distributed devices.

If several Profinet devices are connected in a line (daisy chain), it is possible to further optimise the cyclic data exchange with Dynamic Frame Packing (DFP). For this purpose, the controller puts all output data for all devices into a single IRT frame. At the passing IRT frame, each Device takes out the data intended for the device, i.e. the IRT frame becomes shorter and shorter. For the data from the different devices to the controller, the IRT frame is dynamically assembled. The great efficiency of the DFP lies in the fact that the IRT frame is always only as extensive as necessary and that the data from the controller to the devices can be transmitted in full duplex simultaneously with the data from the devices to the controller.

Technology of Class D (CC-D)

Class D offers the same services to the user as Class C, with the difference that these services are provided using the mechanisms of Time-Sensitive Networking (TSN) defined by IEEE.

The Remote Service Interface (RSI) is used as a replacement for the Internet protocol suite. Thus, this application class D is implemented independently of IP addresses. The protocol stack will be smaller and independent of future Internet versions (IPv6).

The TSN is not a consistent, self-contained protocol definition, but a collection of different protocols with different characteristics that can be combined almost arbitrarily for each application. For use in industrial automation, a subset is compiled in IEC/IEEE standard 60802 "Joint Profile TSN for Industrial Automation". A subset is used in the Profinet specification version 2.4 for implementing class D.[20]

In this specification, a distinction is made between two applications:

  • isochronous, cyclic data exchange with short, limited latency time (Isochronous Cyclic Real Time) for applications in Motion Control and distributed control technology
  • Cyclic data exchange with limited latency time (Cyclic Real Time) for general automation tasks

For the isochronous data exchange the clocks of the participants must be synchronized. For this purpose, the specifications of the Precision Time Protocol according to IEC 61588 for time synchronization with TSN[21] are adapted accordingly.

The telegrams are arranged in queues according to the priorities provided in the VLAN tag. The Time-Aware Shaper (TAS)[22] now specifies a clock pulse with which the individual queues are processed in a switch. This leads to a time-slot procedure where the isochronous, cyclical data is transmitted with the highest priority, the cyclical data with the second priority before all acyclic data. This reduces the latency time and also the jitter for the cyclic data. If a data telegram with low priority lasts too long, it can be interrupted by a cyclic data telegram with high priority and transmitted further afterwards. This procedure is called Frame Preemption[23] and is mandatory for CC-D.

Implementation of Profinet interface

For the realization[24] of a Profinet interface as controller or device, no additional hardware requirements are required for Profinet (CC-A and CC-B) that cannot be met by a common Ethernet interface (100BASE-TX or 100BASE-FX). To enable a simpler line topology, the installation of a switch with 2 ports in a device is recommended.

For the realization of class C (CC-C) devices, an extension of the hardware with time synchronization with the Precision Time Protocol (PTP) and the functionalities of bandwidth reservation is required. For class D (CC-D) devices, the hardware must support the required functionalities of Time-Sensitive Networking (TSN) according to IEEE standards.

The method of implementation[25] depends on the design and performance of the device and the expected quantities. The alternatives are

  • Development in-house[26] or with a service provider
  • Use of ready-made building blocks or individual design
  • Execution in fixed design ASIC, reconfigurable in FPGA technology, as plug-in module or as software component.

History

At the general meeting of the Profibus user organisation in 2000, the first concrete discussions for a successor to Profibus based on Ethernet took place. Just one year later, the first specification of Component Based Automation (CBA) was published and presented at the Hanover Fair. In 2002, the Profinet CBA became part of the international standard IEC 61158 / IEC 61784-1.

A Profinet CBA system [27] consists of different automation components. One component comprises all mechanical, electrical and information technology variables. The component may have been created with the usual programming tools. To describe a component, a Profinet Component Description (PCD) file is created in XML. A planning tool loads these descriptions and allows the logical connections between the individual components to be created to implement a plant.

The basic idea behind Profinet CBA was that in many cases it is possible to divide an entire automation system into autonomously operating - and thus manageable - subsystems. The structure and functionality may well be found in several plants in identical or slightly modified form. Such so-called Profinet components are normally controlled by a manageable number of input signals. Within the component, a control program written by the user executes the required functionality and sends the corresponding output signals to another controller. The communication of a component-based system is planned instead of programmed. Communication with Profinet CBA was suitable for bus cycle times of approx. 50 to 100 ms.

Individual systems show how these concepts can be successfully implemented in the application. However, Profinet CBA does not find the expected acceptance in the market and will no longer be listed in the IEC 61784-1 standard from the 4th edition of 2014.

In 2003 the first specification of Profinet IO (IO = Input Output) was published. The application interface of the Profibus DP (DP = Decentralized Periphery), which was successful on the market, was adopted and supplemented with current protocols from the Internet. In the following year, the extension with isochronous transmission follows, which makes Profinet IO suitable for motion control applications. Profisafe is adapted so that it can also be used via Profinet. With the clear commitment of AIDA[28] to Profinet in 2004, acceptance in the market is given. In 2006 Profinet IO becomes part of the international standard IEC 61158 / IEC 61784-2.

In 2007, according to the neutral count, 1 million Profinet devices have already been installed, in the following year this number doubles to 2 million. By 2019, a total of 26 million[29] devices sold by the various manufacturers are reported.

In 2019, the specification for Profinet was completed with Time-Sensitive Networking (TSN),[30] thus introducing the CC-D conformance class.

Further reading

  • Powell, James; Vandelinde, Henry. Catching the Process Fieldbus: An Introduction to Profibus and Profinet. PI North America, download for free.
  • Popp, Manfred (2015). Industrial communication with PROFINET. PROFIBUS Nutzerorganisation e.V. (PNO). Order no.: 4.182.
  • Xiu, Ji (2019-07-12). PROFINET in Practice: Installation, Maintenance, Design and System Engineering. Independently published. ISBN 978-1-07707-721-8.
  • Pigan, Raimond; Metter, Mark (2008-12-03). Automating with PROFINET: Industrial Communication Based on Industrial Ethernet. Publicis. ISBN 978-3-89578-294-7.

Notes

  1. ^ The station name is a user-configurable alpha-numeric description of up to 240 characters

References

  1. ^ a b c d e f g h i j k l m n "PROFINET System Description". PROFIBUS Nutzerorganisation e.V. October 2014. Order Number 4.132.
  2. ^ a b c d e f g h Manfred Popp. Industrial communication with PROFINET. PROFIBUS Nutzerorganisation e.V. (PNO). Order no.: 4.182.
  3. ^ "PROFINET Commander – Take Command of your PROFINET Network". profinetcommander.com. Retrieved 2020-04-14.
  4. ^ "PRONETA - PROFINET Portfolio - Siemens Global Website". Retrieved 2020-04-14.
  5. ^ Kirrmann, H. (2005). Fault Tolerant Computing in Industrial Automation (PDF)
  6. ^ "PROFIsafe System Description". Documentation. Profinet International. 2016. Retrieved 2020-04-01.
  7. ^ "Functional Safety". Learning Modules. Profinet University. Retrieved 2020-04-02.
  8. ^ "System Redundancy". Learning Modules. Profinet University. Retrieved 2020-04-02.
  9. ^ "Security extensions for Profinet". PI White Paper. Profinet International. 2019. Retrieved 2020-04-01.
  10. ^ "Improving Industrial Control System Cybersecurity with Defense-in-Depth Strategies" (PDF). Recommended Practice. Department of Homeland Security. 2016. Retrieved 2020-04-01.
  11. ^ "How to get a certificate for a Profinet device". Test and Certification. Profinet International. 2019. Retrieved 2020-04-01.
  12. ^ "Application Profiles". Learning Modules. Profinet University. Retrieved 2020-04-02.
  13. ^ "List of profils". PI Profile. Profinet International. Retrieved 2020-04-01.
  14. ^ a b "Drives and Motion with PROFINET". PI White Paper. Profinet International. 2012-11-21. Retrieved 2020-04-03.
  15. ^ "PROFINET – The Solution Platform for Process Automation". PI White Paper. Profinet International. 2018. Retrieved 2020-04-03.
  16. ^ "Process Automation". Learning Modules. Profinet University. Retrieved 2020-04-03.
  17. ^ "Process Control Devices". PI Specification. Profinet International. 2018-05-09.
  18. ^ "FieldComm Group, ODVA and PI Provide Joint Update on an Advanced Physical Layer for Industrial Ethernet". Press release. Profinet International. 2019-11-25. Retrieved 2020-04-03.
  19. ^ PROFINET Montage / Cabling and Assembly. PROFIBUS Nutzerorganisation e.V. (PNO). 21 November 2019. Order no.: 8.072, free download.
  20. ^ "Profinet over TSN Guideline". PI Specification. Profinet International. 2019. Retrieved 2019-10-30.
  21. ^ "IEEE 802.1ASrev Timing and Synchronization". 802 Standard. IEEE. 2019. Retrieved 2019-10-31.
  22. ^ "IEEE 802.1Qbv Enhancements for Scheduled Traffic". 802 Standard. IEEE. Retrieved 2019-10-30.
  23. ^ "IEEE 802.1Qbu Frame Preemption". 802 Standard. IEEE. Retrieved 2019-10-31.
  24. ^ "The Easy Way to PROFINET Technology". PI North America. 2019-08-02. Retrieved 2020-04-14.
  25. ^ "Profinet development". Profinet University. 2019-08-02. Retrieved 2020-04-14.
  26. ^ "PROFINET Field Devices: Recommendations for Design and Implementation". PI International. 2018. Order no.: 8.202 free download. Retrieved 2020-04-14.
  27. ^ Profinet, Technology and Application (PDF) First historic version of a system description for Profinet CBA
  28. ^ "AIDA goes PROFINET". Press release. Profinet International. 2004-11-24. Retrieved 2020-04-02.
  29. ^ "PROFIsafe and IO-Link pass the 10 million mark". Press release. Profinet International. 2019-04-01. Retrieved 2020-04-02.
  30. ^ "Next steps along the "PROFINET over TSN" roadmap". Press release. Profinet International. 2019-11-27. Retrieved 2020-04-02.

External links

  • PROFIBUS & PROFINET International (PI)
  • PROFINET Technology Page
  • PROFIBUS International
  • PROFIsafe web portal
  • PROFINET University
  • wireshark PROFINET Wiki
  • PROFINET Community Stack
  • p-net - An open-source PROFINET device stack

profinet, usually, styled, profinet, portmanteau, process, field, network, industry, technical, standard, data, communication, over, industrial, ethernet, designed, collecting, data, from, controlling, equipment, industrial, systems, with, particular, strength. Profinet usually styled as PROFINET as a portmanteau for Process Field Network is an industry technical standard for data communication over Industrial Ethernet designed for collecting data from and controlling equipment in industrial systems with a particular strength in delivering data under tight time constraints The standard is maintained and supported by Profibus and Profinet International an umbrella organization headquartered in Karlsruhe Germany ProfinetCommunication protocolPurposeReal time Ethernet for industrial AutomationDeveloper s PROFIBUS amp PROFINET InternationalIntroduction2003 20 years ago 2003 Based onEthernet ProfibusOSI layerApplication layerRFC s IEC 61784 2 IEC 61158 Contents 1 Functionalities 1 1 Overview 1 2 Conformance Classes CC 1 3 Device types 1 4 System structure 1 5 Relations 1 6 Engineering 2 Dependability 2 1 Functional safety Profisafe 2 2 Increased availability 2 2 1 System redundancy 2 2 2 Media redundancy 2 3 Security 3 Application Profiles 3 1 Drives 3 2 Energy 3 3 Process automation 3 3 1 Process devices 3 3 2 Advanced Physical Layer 4 Technology 4 1 Profinet protocols 4 2 Technology of Conformance Classes 4 3 Technology of Class A CC A 4 3 1 Management of the Application Relations AR 4 4 Technology of Class B CC B 4 5 Technology of Class C CC C 4 6 Technology of Class D CC D 5 Implementation of Profinet interface 6 History 7 Further reading 8 Notes 9 References 10 External linksFunctionalities EditOverview Edit Profinet implements the interfacing to peripherals 1 2 It defines the communication with field connected peripheral devices Its basis is a cascading real time concept Profinet defines the entire data exchange between controllers called IO Controllers and the devices called IO Devices as well as parameter setting and diagnosis IO Controllers are typically a PLC DCS or IPC whereas IO Devices can be varied I O blocks drives sensors or actuators The Profinet protocol is designed for the fast data exchange between Ethernet based field devices and follows the provider consumer model 1 Field devices in a subordinate Profibus line can be integrated in the Profinet system seamlessly via an IO Proxy representative of a subordinate bus system Conformance Classes CC Edit Applications with Profinet can be divided according to the international standard IEC 61784 2 into four conformance classes In Conformance Class A CC A only the devices are certified A manufacturer certificate is sufficient for the network infrastructure This is why structured cabling or a wireless local area network for mobile subscribers can also be used Typical applications can be found in infrastructure e g motorway or railway tunnels or in building automation Conformance Class B CC B stipulates that the network infrastructure also includes certified products and is structured according to the guidelines of Profinet Shielded cables increase robustness and switches with management functions facilitate network diagnostics and allow the network topology to be captured as desired for controlling a production line or machine Process automation requires increased availability which can be achieved through media and system redundancy For a device to adhere to Conformance Class B it must communicate successfully via Profinet have two ports integrated switch and support SNMP With Conformance Class C CC C positioning systems can be implemented with additional bandwidth reservation and application synchronization Conformance Class C devices additionally communicate via Profinet IRT For Conformance Class D CC D Profinet is used via Time Sensitive Networking TSN The same functions can be achieved as with CC C In contrast to CC A and CC B the complete communication cyclic and acyclic between controller and device takes place on Ethernet layer 2 The Remote Service Interface RSI was introduced for this purpose Functionalities of Profinet Conformance ClassesFunctionality Class A CC A Class B CC B Class C CC C Class D CC D Basic functionality RT Communication Cyclic I O Parameter Alarms RT Communication Cyclic I O Parameter Alarms Network diagnostics Topology detection System redundancy RT Communication Cyclic I O Parameter Alarms Network diagnostics Topology detection Bandwidth reservation IRT Synchronisation Seamless media redundancy RT Communication Cyclic I O Parameter Alarms Network diagnostics Topology detection Bandwidth reservation TSN Synchronisation System redundancy Seamless media redundancyCertification Controller Devices Controller Devices Network components Controller Devices Network components Controller Devices Network componentsCabling IEC 61784 5 3 and IEC 24702 Copper Fibre optics Wireless IEC 61784 5 3 Copper Fibre optics IEC 61784 5 3 Copper Fibre optics IEC 61784 5 3 Copper Fibre opticsTypical application Infrastructure facilities Building automation Factory automation Process automation Motion control Universal Device types Edit A Profinet system consists of the following devices 1 3 The IO Controller which controls the automation task The IO Device which is a field device monitored and controlled by an IO Controller An IO Device may consist of several modules and sub modules The IO Supervisor is software typically based on a PC for setting parameters and diagnosing individual IO Devices System structure Edit A minimal Profinet IO System consists of at least one IO Controller that controls one or more IO Devices In addition one or more IO Supervisors can optionally be switched on temporarily for the engineering of the IO Devices if required If two IO Systems are in the same IP network the IO Controllers can also share an input signal as shared input in which they have read access to the same submodule in an IO Device 1 3 2 This simplifies the combination of a PLC with a separate safety controller or motion control Likewise an entire IO Device can be shared as a shared device 1 11 in which individual submodules of an IO Device are assigned to different IO Controllers Each automation device with an Ethernet interface can simultaneously fulfill the functionality of an IO Controller and an IO Device If a controller for a partner controller acts as an IO Device and simultaneously controls its periphery as an IO Controller the tasks between controllers can be coordinated without additional devices Relations Edit An Application Relation AR is established between an IO Controller and an IO Device These ARs are used to define Communication Relations CR with different characteristics for the transfer of parameters cyclic exchange of data and handling of alarms 1 4 Engineering Edit The project engineering 1 5 2 of an IO system is nearly identical to the Profibus in terms of look and feel The properties of an IO Device are described by the device manufacturer in a GSD file General Station Description The language used for this is GSDML GSD Markup Language an XML based language The GSD file serves an engineering environment as a basis for planning the configuration of a Profinet IO system All Profinet field devices determine their neighbors 1 8 This means that field devices can be exchanged in the event of a fault without additional tools and prior knowledge By reading out this information the plant topology can be displayed graphically for better clarity The engineering can be supported by tools such as PROFINET Commander 3 or PRONETA 4 Dependability EditProfinet is also increasingly being used in critical applications There is always a risk that the required functions cannot be fulfilled This risk can be reduced by specific measures as identified by a dependability 5 analyses The following objectives are in the foreground Safety Ensuring functional safety The system should go into a safe state in the event of a fault Availability Increasing the availability In the event of a fault the system should still be able to perform the minimum required function Security Information security is to ensure the integrity of the system These goals can interfere with or complement each other Functional safety Profisafe Edit Main article Profisafe Profisafe 6 defines how safety related devices emergency stop buttons light grids overfill prevention devices communicate with safety controllers via Profinet in such a safe way that they can be used in safety related automation tasks up to Safety Integrity Level 3 SIL according to IEC 61508 Performance Level e PL according to ISO 13849 or Category 4 according to EN 954 1 Profisafe implements safe communication via a profile 7 i e via a special format of the user data and a special protocol It is designed as a separate layer on top of the fieldbus application layer to reduce the probability of data transmission errors The Profisafe messages use standard fieldbus cables and messages They do not depend on error detection mechanisms of underlying transmission channels and thus supports securing of whole communication paths including backplanes inside controllers or remote I O The Profisafe protocol uses error and failure detection mechanisms such as Consecutive numbering Timeout monitoring Source destination authentication Cyclic redundancy checking CRC and is defined in the IEC 61784 3 3 standard Increased availability Edit High availability 8 is one of the most important requirements in industrial automation both in factory and process automation The availability of an automation system can be increased by adding redundancy for critical elements A distinction can be made between system and media redundancy System redundancy Edit System redundancy can also be implemented with Profinet to increase availability In this case two IO Controllers that control the same IO Device are configured The active IO Controller marks its output data as primary Output data that is not marked is ignored by an IO Device in a redundant IO System In the event of an error the second IO Controller can therefore take control of all IO Devices without interruption by marking its output data as primary How the two IO Controllers synchronize their tasks is not defined in Profinet and is implemented differently by the various manufacturers offering redundant control systems Media redundancy Edit Profinet offers two media redundancy solutions The Media Redundancy Protocol MRP allows the creation of a protocol independent ring topology with a switching time of less than 50 ms This is often sufficient for standard real time communication with Profinet To switch over the redundancy in the event of an error without time delay the Media Redundancy for Planned Duplication MRPD must be used as a seamless media redundancy concept In the MRPD the cyclic real time data is transmitted in both directions in the ring shaped topology A time stamp in the data packet allows the receiver to remove the redundant duplicates Security Edit The IT security concept 9 for Profinet assumes a defense in depth 10 approach In this approach the production plant is protected against attacks particularly from outside by a multi level perimeter including firewalls In addition further protection is possible within the plant by dividing it into zones using firewalls In addition a security component test ensures that the Profinet components are resistant to overload to a defined extent 11 This concept is supported by organizational measures in the production plant within the framework of a security management system according to ISO 27001 Application Profiles EditFor a smooth interaction of the devices involved in an automation solution they must correspond in their basic functions and services Standardization is achieved by profiles 12 with binding specifications for functions and services The possible functions of communication with Profinet are restricted and additional specifications regarding the function of the field device are prescribed These can be cross device class properties such as a safety relevant behavior Common Application Profiles or device class specific properties Specific Application Profiles 13 A distinction is made between Device profiles for e g robots drives PROFIdrive process devices encoders pumps Industry Profiles for e g laboratory technology or rail vehicles Integration Profiles for the integration of subsystems such as IO Link systemsDrives Edit PROFIdrive 14 is the modular device profile for drive devices It was jointly developed by manufacturers and users in the 1990s and since then in conjunction with Profibus and from version 4 0 also with Profinet it has covered the entire range from the simplest to the most demanding drive solutions Energy Edit Another profile is PROFIenergy which includes services for real time monitoring of energy demand This was requested in 2009 by the AIDA group of German automotive Manufacturers Audi BMW Mercedes Benz Porsche and Volkswagen who wished to have a standardised way of actively managing energy usage in their plants High energy devices and sub systems such as robots lasers and even paint lines are the target for this profile which will help reduce a plant s energy costs by intelligently switching the devices into sleep modes to take account of production breaks both foreseen e g weekends and shut downs and unforeseen e g breakdowns Process automation Edit Modern process devices have their own intelligence and can take over part of the information processing or the overall functionality in automation systems For integration into a Profinet system 15 16 a two wire Ethernet is required in addition to increased availability Process devices Edit The profile PA Devices 17 defines for different classes of process devices all functions and parameters typically used in process devices for the signal flow from the sensor signal from the process to the pre processed process value which is read out to the control system together with a measured value status The PA Devices profile contains device data sheets for Pressure and differential pressure Level temperature and flow rate Analog and digital inputs and outputs Valves and actuators Analysis equipmentAdvanced Physical Layer Edit Ethernet Advanced Physical Layer Ethernet APL 18 describes a physical layer for the Ethernet communication technology which is especially developed for the requirements of the process industries The development of Ethernet APL was determined by the need for communication at high speeds and over long distances the supply of power and communications signals via common single twisted pair 2 wire cable as well as protective measures for the safe use within explosion hazardous areas Ethernet APL opens the possibility for Profinet to be incorporated into process instruments Technology EditProfinet protocols Edit Profinet uses the following protocols in the different layers 2 15 of the OSI model OSI Layer Profinet7a Application Fieldbus Application Layer FAL Services and protocols OPC UA7b RSI empty empty RPC 6 Presentation 5 Session4 Transport UDP TCP3 Network IP2 Data Link TSN CSMA CD1 Physical EthernetLayers 1 2 Mainly full duplex with 100 MBit s electrical 100BASE TX or optical 100BASE FX according to IEEE 802 3 are recommended 19 as device connections Autocrossover is mandatory for all connections so that the use of crossover cables can be avoided From IEEE 802 1Q the VLAN with priority tagging is used All real time data are thus given the highest possible priority 6 and are therefore forwarded by a switch with a minimum delay The Profinet protocol can be recorded and displayed with any Ethernet analysis tool Wireshark is capable of decoding Profinet telegrams The Link Layer Discovery Protocol LLDP has been extended with additional parameters so that in addition to the detection of neighbors the propagation time of the signals on the connection lines can be communicated Layers 3 6 Either the Remote Service Interface RSI protocol or the Remote Procedure Call RPC protocol is used for the connection setup and the acyclic services The RPC protocol is used via User Datagram Protocol UDP and Internet Protocol IP with the use of IP addresses The Address Resolution Protocol ARP is extended for this purpose with the detection of duplicate IP addresses The Discovery and basic Configuration Protocol DCP is mandatory for the assignment of IP addresses Optionally the Dynamic Host Configuration Protocol DHCP can also be used for this purpose No IP addresses are used with the RSI protocol Thus IP can be used in the operating system of the field device for other protocols such as OPC Unified Architecture OPC UA Layer 7 Various protocols 1 are defined to access the services of the Fieldbus Application Layer FAL The RT Real Time protocol for class A amp B applications with cycle times in the range of 1 10 ms The IRT Isochronous Real Time protocol for application class C allows cycle times below 1 ms for drive technology applications This can also be achieved with the same services via Time Sensitive Networking TSN Technology of Conformance Classes Edit The functionalities of Profinet IO are realized with different technologies and protocols Technology and protocols of Profinet Conformance ClassesFunctionality Technology Protocol CC A CC B CC C CC DCyclic data exchangeAcyclic parameter dataDevice diagnostics alarmsDevice identificationTopology information RTRead Write RecordAlarm HandlingI amp M 0LLDP mandatory mandatory mandatory mandatoryMultiple access to inputsSplit device functions to controllersExtended device identification Shared InputShared DeviceI amp M 1 4 optional optional optional optionalNetwork diagnosticsPort related statistics SNMPPDEV mandatory mandatory MandatorySystem redundancy 2 controllers mandatory for process automation optional optionalAutomatic addressingConfiguration change during operationTime stamping of process dataMedia redundancyFast restart LLDP DCPDRIEC 61588MRPFSU optional optional optionalBandwidth reservation gt 250 ms cycle time IRT mandatory Bandwidth reservation lt 250 ms Cycle timeClock synchronicityOptimized operating modeMedia redundancy without latency IRTIRT PTPDFPMRPD optional Bandwidth reservationClock synchronicity at 100MBOptimized operating mode TSNTASFrame Preemption mandatory Technology of Class A CC A Edit The basic function of the Profinet is the cyclic data exchange between the IO Controller as producer and several IO Devices as consumers of the output data and the IO Devices as producers and the IO Controller as consumer of the input data 1 Each communication relationship IO data CR between the IO Controller and an IO Device defines the number of data and the cycle times All Profinet IO Devices must support device diagnostics and the safe transmission of alarms via the communication relation for alarms Alarm CR In addition device parameters can be read and written with each Profinet device via the acyclic communication relation Record Data CR The data set for the unique identification of an IO Device the Identification and Maintenance Data Set 0 I amp M 0 must be installed by all Profinet IO Devices Optionally further information can be stored in a standardized format as I amp M 1 4 For real time data cyclic data and alarms the Profinet Real Time RT telegrams are transmitted directly via Ethernet UDP IP is used for the transmission of acyclic data Management of the Application Relations AR Edit The Application Relation AR is established between an IO Controller and every IO Device to be controlled Inside the ARs are defined the required CRs The Profinet AR life cycle consists of address resolution connection establishment parameterization process IO data exchange alarm handling and termination Address resolution A Profinet IO Device is identified on the Profinet network by its station name note 1 Connection establishment parameterization and alarm handling are implemented with User Datagram Protocol UDP which requires that the device also be assigned an IP address After identifying the device by its station name the IO Controller assigns the pre configured IP address to the device Connection establishment Connection establishment starts with the IO Controller sending a connect request to the IO Device The connect request establishes an Application Relationship AR containing a number of Communication Relationships CRs between the IO Controller and IO Device 2 In addition to the AR and CRs the connect request specifies the modular configuration of the IO Device the layout of the process IO data frames the cyclic rate of IO data exchange and the watchdog Acknowledgement of the connect request by the IO Device allows parameterization to follow From this point forward both the IO Device and IO Controller start exchanging cyclic process I O data frames The process I O data frames don t contain valid data at this point but they start serving as keep alive to keep the watchdog from expiring Parameterization The IO Controller writes parameterization data to each IO Device sub module in accordance with the General Station Description Mark up Language GSDML file Once all sub modules have been configured the IO Controller signals that parameterization has ended The IO Device responds by signaling application readiness which allows process IO data exchange and alarm handling to ensue 2 Process IO data exchange alarm handling The IO Device followed by the IO Controller start to cyclically refresh valid process I O data The IO Controller processes the inputs and controls the outputs of the IO Device 2 Alarm notifications are exchanged acyclically between the IO Controller and IO Device as events and faults occur 1 Termination The connection between the IO Device and IO Controller terminates when the watchdog expires 2 Watchdog expiry is the result of a failure to refresh cyclic process I O data by the IO Controller or the IO Device 1 Unless the connection was intentionally terminated at the IO Controller the IO Controller will try to restart the Profinet Application Relation Technology of Class B CC B Edit In addition to the basic Class A functions Class B devices must support additional functionalities 1 These functionalities primarily support the commissioning operation and maintenance of a Profinet IO system and are intended to increase the availability of the Profinet IO system Support of network diagnostics with the Simple Network Management Protocol SNMP is mandatory Likewise the Link Layer Discovery Protocol LLDP for neighborhood detection including the extensions for Profinet must be supported by all Class B devices This also includes the collection and provision of Ethernet port related statistics for network maintenance With these mechanisms the topology of a Profinet IO network can be read out at any time and the status of the individual connections can be monitored If the network topology is known automatic addressing of the nodes can be activated by their position in the topology This considerably simplifies device replacement during maintenance since no more settings need to be made High availability of the IO system is particularly important for applications in process automation and process engineering For this reason special procedures have been defined for Class B devices with the existing relationships and protocols This allows system redundancy with two IO Controllers accessing the same IO Devices simultaneously In addition there is a prescribed procedure Dynamic Reconfiguration DR how the configuration of an IO Device can be changed with the help of these redundant relationships without losing control over the IO Device Technology of Class C CC C Edit For the functionalities of Conformance Class C CC C the Isochronous Real Time 1 IRT protocol is mainly used With the bandwidth reservation a part of the available transmission bandwidth of 100 MBit s is reserved exclusively for real time tasks A procedure similar to a time multiplexing method is used The bandwidth is divided into fixed cycle times which in turn are divided into phases The red phase is reserved exclusively for class C real time data in the orange phase the time critical messages are transmitted and in the green phase the other Ethernet messages are transparently passed through To ensure that maximum Ethernet telegrams can still be passed through transparently the green phase must be at least 125 ms long Thus cycle times under 250 ms are not possible in combination with unchanged Ethernet In order to achieve shorter cycle times down to 31 25 ms the Ethernet telegrams of the green phase are optionally broken down into fragments These short fragments are now transmitted via the green phase This fragmentation mechanism is transparent to the other participants on the Ethernet and therefore not recognizable In order to implement these bus cycles for bandwidth reservation precise clock synchronization of all participating devices including the switches is required with a maximum deviation of 1 ms This clock synchronization is implemented with the Precision Time Protocol PTP according to the IEEE 1588 2008 1588 V2 standard All devices involved in the bandwidth reservation must therefore be in the same time domain For position control applications for several axes or for positioning processes according to the PROFIdrive 14 drive profile of application classes 4 6 not only must communication be timely but the actions of the various drives on a Profinet must also be coordinated and synchronized The clock synchronization of the application program to the bus cycle allows control functions to be implemented that are executed synchronously on distributed devices If several Profinet devices are connected in a line daisy chain it is possible to further optimise the cyclic data exchange with Dynamic Frame Packing DFP For this purpose the controller puts all output data for all devices into a single IRT frame At the passing IRT frame each Device takes out the data intended for the device i e the IRT frame becomes shorter and shorter For the data from the different devices to the controller the IRT frame is dynamically assembled The great efficiency of the DFP lies in the fact that the IRT frame is always only as extensive as necessary and that the data from the controller to the devices can be transmitted in full duplex simultaneously with the data from the devices to the controller Technology of Class D CC D Edit Class D offers the same services to the user as Class C with the difference that these services are provided using the mechanisms of Time Sensitive Networking TSN defined by IEEE The Remote Service Interface RSI is used as a replacement for the Internet protocol suite Thus this application class D is implemented independently of IP addresses The protocol stack will be smaller and independent of future Internet versions IPv6 The TSN is not a consistent self contained protocol definition but a collection of different protocols with different characteristics that can be combined almost arbitrarily for each application For use in industrial automation a subset is compiled in IEC IEEE standard 60802 Joint Profile TSN for Industrial Automation A subset is used in the Profinet specification version 2 4 for implementing class D 20 In this specification a distinction is made between two applications isochronous cyclic data exchange with short limited latency time Isochronous Cyclic Real Time for applications in Motion Control and distributed control technology Cyclic data exchange with limited latency time Cyclic Real Time for general automation tasksFor the isochronous data exchange the clocks of the participants must be synchronized For this purpose the specifications of the Precision Time Protocol according to IEC 61588 for time synchronization with TSN 21 are adapted accordingly The telegrams are arranged in queues according to the priorities provided in the VLAN tag The Time Aware Shaper TAS 22 now specifies a clock pulse with which the individual queues are processed in a switch This leads to a time slot procedure where the isochronous cyclical data is transmitted with the highest priority the cyclical data with the second priority before all acyclic data This reduces the latency time and also the jitter for the cyclic data If a data telegram with low priority lasts too long it can be interrupted by a cyclic data telegram with high priority and transmitted further afterwards This procedure is called Frame Preemption 23 and is mandatory for CC D Implementation of Profinet interface EditFor the realization 24 of a Profinet interface as controller or device no additional hardware requirements are required for Profinet CC A and CC B that cannot be met by a common Ethernet interface 100BASE TX or 100BASE FX To enable a simpler line topology the installation of a switch with 2 ports in a device is recommended For the realization of class C CC C devices an extension of the hardware with time synchronization with the Precision Time Protocol PTP and the functionalities of bandwidth reservation is required For class D CC D devices the hardware must support the required functionalities of Time Sensitive Networking TSN according to IEEE standards The method of implementation 25 depends on the design and performance of the device and the expected quantities The alternatives are Development in house 26 or with a service provider Use of ready made building blocks or individual design Execution in fixed design ASIC reconfigurable in FPGA technology as plug in module or as software component History EditAt the general meeting of the Profibus user organisation in 2000 the first concrete discussions for a successor to Profibus based on Ethernet took place Just one year later the first specification of Component Based Automation CBA was published and presented at the Hanover Fair In 2002 the Profinet CBA became part of the international standard IEC 61158 IEC 61784 1 A Profinet CBA system 27 consists of different automation components One component comprises all mechanical electrical and information technology variables The component may have been created with the usual programming tools To describe a component a Profinet Component Description PCD file is created in XML A planning tool loads these descriptions and allows the logical connections between the individual components to be created to implement a plant The basic idea behind Profinet CBA was that in many cases it is possible to divide an entire automation system into autonomously operating and thus manageable subsystems The structure and functionality may well be found in several plants in identical or slightly modified form Such so called Profinet components are normally controlled by a manageable number of input signals Within the component a control program written by the user executes the required functionality and sends the corresponding output signals to another controller The communication of a component based system is planned instead of programmed Communication with Profinet CBA was suitable for bus cycle times of approx 50 to 100 ms Individual systems show how these concepts can be successfully implemented in the application However Profinet CBA does not find the expected acceptance in the market and will no longer be listed in the IEC 61784 1 standard from the 4th edition of 2014 In 2003 the first specification of Profinet IO IO Input Output was published The application interface of the Profibus DP DP Decentralized Periphery which was successful on the market was adopted and supplemented with current protocols from the Internet In the following year the extension with isochronous transmission follows which makes Profinet IO suitable for motion control applications Profisafe is adapted so that it can also be used via Profinet With the clear commitment of AIDA 28 to Profinet in 2004 acceptance in the market is given In 2006 Profinet IO becomes part of the international standard IEC 61158 IEC 61784 2 In 2007 according to the neutral count 1 million Profinet devices have already been installed in the following year this number doubles to 2 million By 2019 a total of 26 million 29 devices sold by the various manufacturers are reported In 2019 the specification for Profinet was completed with Time Sensitive Networking TSN 30 thus introducing the CC D conformance class Further reading EditPowell James Vandelinde Henry Catching the Process Fieldbus An Introduction to Profibus and Profinet PI North America download for free Popp Manfred 2015 Industrial communication with PROFINET PROFIBUS Nutzerorganisation e V PNO Order no 4 182 Xiu Ji 2019 07 12 PROFINET in Practice Installation Maintenance Design and System Engineering Independently published ISBN 978 1 07707 721 8 Pigan Raimond Metter Mark 2008 12 03 Automating with PROFINET Industrial Communication Based on Industrial Ethernet Publicis ISBN 978 3 89578 294 7 Notes Edit The station name is a user configurable alpha numeric description of up to 240 charactersReferences Edit a b c d e f g h i j k l m n PROFINET System Description PROFIBUS Nutzerorganisation e V October 2014 Order Number 4 132 a b c d e f g h Manfred Popp Industrial communication with PROFINET PROFIBUS Nutzerorganisation e V PNO Order no 4 182 PROFINET Commander Take Command of your PROFINET Network profinetcommander com Retrieved 2020 04 14 PRONETA PROFINET Portfolio Siemens Global Website Retrieved 2020 04 14 Kirrmann H 2005 Fault Tolerant Computing in Industrial Automation PDF PROFIsafe System Description Documentation Profinet International 2016 Retrieved 2020 04 01 Functional Safety Learning Modules Profinet University Retrieved 2020 04 02 System Redundancy Learning Modules Profinet University Retrieved 2020 04 02 Security extensions for Profinet PI White Paper Profinet International 2019 Retrieved 2020 04 01 Improving Industrial Control System Cybersecurity with Defense in Depth Strategies PDF Recommended Practice Department of Homeland Security 2016 Retrieved 2020 04 01 How to get a certificate for a Profinet device Test and Certification Profinet International 2019 Retrieved 2020 04 01 Application Profiles Learning Modules Profinet University Retrieved 2020 04 02 List of profils PI Profile Profinet International Retrieved 2020 04 01 a b Drives and Motion with PROFINET PI White Paper Profinet International 2012 11 21 Retrieved 2020 04 03 PROFINET The Solution Platform for Process Automation PI White Paper Profinet International 2018 Retrieved 2020 04 03 Process Automation Learning Modules Profinet University Retrieved 2020 04 03 Process Control Devices PI Specification Profinet International 2018 05 09 FieldComm Group ODVA and PI Provide Joint Update on an Advanced Physical Layer for Industrial Ethernet Press release Profinet International 2019 11 25 Retrieved 2020 04 03 PROFINET Montage Cabling and Assembly PROFIBUS Nutzerorganisation e V PNO 21 November 2019 Order no 8 072 free download Profinet over TSN Guideline PI Specification Profinet International 2019 Retrieved 2019 10 30 IEEE 802 1ASrev Timing and Synchronization 802 Standard IEEE 2019 Retrieved 2019 10 31 IEEE 802 1Qbv Enhancements for Scheduled Traffic 802 Standard IEEE Retrieved 2019 10 30 IEEE 802 1Qbu Frame Preemption 802 Standard IEEE Retrieved 2019 10 31 The Easy Way to PROFINET Technology PI North America 2019 08 02 Retrieved 2020 04 14 Profinet development Profinet University 2019 08 02 Retrieved 2020 04 14 PROFINET Field Devices Recommendations for Design and Implementation PI International 2018 Order no 8 202 free download Retrieved 2020 04 14 Profinet Technology and Application PDF First historic version of a system description for Profinet CBA AIDA goes PROFINET Press release Profinet International 2004 11 24 Retrieved 2020 04 02 PROFIsafe and IO Link pass the 10 million mark Press release Profinet International 2019 04 01 Retrieved 2020 04 02 Next steps along the PROFINET over TSN roadmap Press release Profinet International 2019 11 27 Retrieved 2020 04 02 External links EditPROFIBUS amp PROFINET International PI PROFINET Technology Page PROFIBUS International PROFIsafe web portal PROFINET University wireshark PROFINET Wiki PROFINET Community Stack p net An open source PROFINET device stack Retrieved from https en wikipedia org w index php title Profinet amp oldid 1167181958, wikipedia, wiki, book, books, library,

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