FAQ
| Is it necessary to have GSD or the other similar documents when the products of the third vendor |  |
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The integration of third party devices into PROFINET IO is identical to the concept used in PROFIBUS. In both systems GSD files are used, however in PROFINET IO these files are XML-based.
| How many PROFIBUS devices can be connected to the proxy? | |
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In the PROFINET standard there is no limitation on the number of PROFIBUS devices which can be connected to a proxy. The Siemens product for example supports up to 64 PROFIBUS slaves.
| Does PROFINET also function with other operating systems, such as Linux and Java? | |
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The PROFINET concept is independent of the operating system. PROFINET stations can be implemented in any form provided that they comply with the PROFINET specification.
Extract from iee 11/2000:
'The runtime software was developed under the stringent requirement of operating system neutrality, to enable easy integration of the PROFINET core software in a wide range of embedded PLCs and systems by adapting it to the individual system - a specific operating system is not a prerequisite.'
| Can PROFINET with IRT use ordinary switch? | |
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No, IRT applications require the specific support of ERTEC ASIC to handle forwarding information and clock synchronization.
| Regarding the IEEE 802.3-based PROFINET, how to ensure the real time functionality of IRT without | |
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PROFINET uses switches as network components with full duplex communication functionality, so no collisions occur in a PROFINET network. Additionally the ERTEC ASIC ensures the handling of the IRT telegrams in pre-defined time slots so that no other telegrams can disturb the IRT-communication.
| Can PROFINET IO devices be related to one specific PROFINET controller? | |
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In contradiction to PROFIBUS, a PROFINET IO-Device can be allocated to several PROFINET IO-Controller.
| If there is a PROFINET network with a ring structure. Are there any limitations regarding the di | |
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One of the advantages of PROFINET is that it enables the creation of flexible network structures. The length, speed and topology depend on the network components you choose for your network. For example, in case of fiber optic with integrated interfaces you can reach up to 300 m between devices. With external components fiber optic distances of up to 26km are possible depending on the type of fiber optic being used and the vendors. In an electrical network the maximum distance between any two devices is 100m.
| What’s the difference between real time data and acyclic data? Is the protocol for real time dat | |
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Real time telegrams are telegrams that have the label 0x8892 in the standard Ethernet frame header. This is independent of whether the communication is cyclic or acyclic. Both real time and non real time communication are simultaneously possible on a PROFINET network.
| How to make the transition from the past industrial Ethernet to PROFINET? Does it need to change | |
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PROFINET is based on Industrial Ethernet. PROFINET brings Industrial Ethernet down to the field level, so that you can directly interconnect to field devices via Ethernet. Industrial Ethernet before was typically used for communication between PLC/PLC and PLC/HMI, i.e. previously no communication to the IO-Devices was possible via Industrial Ethernet. So the same network infrastructure components (switches, cables, connectors) can still be used today with PROFINET.
| What’s the biggest difference between the past industrial Ethernet and PROFINET? | |
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PROFINET is based on Industrial Ethernet. PROFINET IO brings Industrial Ethernet down to the field level, so that you can directly interconnect to field devices via Ethernet. PROFINET CBA supports the building up of distributed modular automation structures.
Industrial Ethernet before was typically used for communication between PLC/PLC and PLC/HMI i.e. previously no communication to the IO-Devices was possible via Industrial Ethernet.
| Does PROFINET support redundancy? | |
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The media redundancy is available for PROFINET. The system redundancy is under specification.
| Is it necessary to use special PROFINET switches or can ordinary industrial Ethernet switches be | |
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PROFINET uses Standard Ethernet switches. Only IRT functionality for Motion Control requires specific switches based on the ERTEC ASICs.
| How is PROFINET handling real-time (RT) and non-real communication (NRT) on one Network system w | |
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RT and NRT communication within one cycle are separated. RT-communication always has the highest priority.
| What is the difference between PROFIBUS and PROFINET? Is there any independent interface? | |
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PROFIBUS is a Fieldbus based communication system. PROFINET is an Ethernet based communication system and offers an easier way to integrate the Automation systems into the company-wide IT-Systems like MES (Manufacturing Execution Systems) or ERP (Enterprise Resource Planning).
The supplier of Automation systems are offering Interfaces for PROFIBUS as well as for PROFINET.
| We are using the Ethernet-controlled network that is connected to both Interbus and PROFIBUS. Wh | |
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PROFINET allows the seamless integration of underlying fieldbus systems according the same principles of data integration by using the unified PROXY technology. This allows reducing costs for product development and engineering.
| What’s the difference in terms of application cases between PROFIBUS ands PROFINET? How would th | |
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From the users point of view there is no difference regarding the application between PROFIBUS and PROFINET.
| What role does the VLAN symbol in the Ethernet data frame play in PROFINET? | |
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The VLAN symbol is always used in every RT-frame. NRT-Frames may use it. With the VLAN-Tag it is possible to increase the priority of a frame to be sent. Normally it is enough to distinguish the priority with our new Ethertype for RT (0x8892). But to ensure interoperability with older Ethernet switches we also use the VLAN-Tag.
| If the existing devices have the Ethernet interface, is it still necessary to employ PROFINET Gat | |
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Only the PROFINET software stack has to be integrated into the device. Usually this has to be done by the device supplier.
| How far is the transmission distance for PROFINET in terms of the data exchange in Siemens’ indus | |
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One of the advantages of PROFINET is that it enables the creation of flexible network structures. The length, speed and topology depend on the network components you choose for your network. For example, in case of fiber optic with integrated interfaces you can reach up to 300 m between devices. With external components fiber optic distances of up to 26km are possible depending on the type of fiber optic being used and the vendors. In an electrical network the maximum distance between any two devices is 100m.
| When PROFIBUS & Interbus should be integrated into PROFINET, what kind of extra devices are neede | |
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Only one proxy device is needed for the integration of each fieldbus system such as PROFIBUS or Interbus into PROFINET.
| If CBA on the cell level should be used, how PLC’s of different vendors can be integrated? | |
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PROFINET CBA is an open standard from PROFIBUS International and is vendor independent. At present vendors such as Phoenix Contact, Bosch as well as Siemens are supporting CBA.
| When the IO point reaches over 200 in a power station, would the capacity of the switch for the n | |
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200 IO points is no problem on a PROFINET network. One of the main advantages of PROFINET compared to PROFIBUS is that you can have more nodes on the network. Please note that any configuration with PROFIBUS can be realized with PROFINET, as far as the number of devices on the network is concerned. PROFINET uses switches as network components with full duplex communication functionality, so no collisions occur in a PROFINET network.
| Is PROFINET applicable to the Process Automation? What’s its relationship with PROFIBUS? | |
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We have already started specifying PROFINET for Process Automation applications. Solutions will be available in 2007. In the meantime PROFIBUS is the best choice. We will ensure that PROFINET allows the simple integration of existing PROFIBUS applications in order to protect any investments you may have made.
| If there will be a project starting now, would you recommend PROFIBUS or PROFINET? | |
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If you are happy with PROFIBUS as a solution today, then you can continue to use PROFIBUS (note PROFIBUS will continue to be developed over the coming years). If however you want to take advantage of the real benefits of PROFINET (e.g. Wireless applications, high performance Motion Control applications, increased diagnostic possibilities particularly via the Web/email, …) then we suggest to use PROFINET.
| How can PROFINET be adapted to the current Microsoft developments (.NET)? | |
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.NET is the Microsoft concept for future e-business applications and does not meet all the requirements of automation.
COM/DCOM is well-proven in automation for communication applications (e.g. OPC).
The current Microsoft concepts will be taken into account during the further development of PROFINET.
| What is a proxy and how does the proxy concept operate in the case of PROFINET? | |
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The proxy principle is part of the PROFINET specification and enables standard PROFIBUS slaves to be integrated into PROFINET concepts. The proxy acts as an intermediary in the communication process between stations on PROFIBUS.
It acts as a converter in the case of communication between stations on PROFIBUS and stations on Ethernet.
| Is PROFINET a concept solely applicable to the field level? | |
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PROFINET is a multi-vendor concept that ranges from the management level down to the field level which defines both the communication and a model for plant-wide engineering.
| With PROFINET, is it always necessary to install two bus systems locally, i.e. Ethernet & PROFIBUS? | |
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Other concepts propagate distributed automation with a single communication medium connected from the office level through to the field level.
The PROFINET specification does not specify the physical characteristics of the transmission network. Pure Ethernet solutions as well as combined Ethernet and PROFIBUS solutions are possible. The strengths of PROFINET lie in the integration of both bus systems in a common concept.
The advantage of this is that in cases in which technical solutions do not exist for Ethernet, PROFIBUS can be used without the need to adapt the fieldbus protocol or field devices. An example of this would be Motion Control tasks or safety-related applications.
| Does PROFINET provide intelligent field devices only on Ethernet? | |
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In PROFINET structures, intelligent field devices, such as Simatic ET 200X with a CPU, can be connected not only to Ethernet but also to PROFIBUS.
| Who supplies the Engineering Tool for PROFINET? | |
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The multi-vendor engineering model of PROFINET allows automation manufacturers to develop their own engineering tools that can be used to configure components and devices from different manufacturers.
