1. What is PROFINET?

PROFINET is an open industrial Ethernet system based on international standards and part of IEC 61158 / IEC 61784-2, which defines what the signal looks like on the wire and what the medium accessing the wire has to do, it also uses industrial Ethernet as the physical layer (defined by IEEE802.3). It is a real-time communication protocol, meaning that devices can exchange data in real time with minimal delays. It is also a deterministic protocol, meaning that data is exchanged with predictable latency. 

Using PROFINET, components can communicate cyclically or acyclically, and exchange diagnostics, safety functions, alarms, and additional information. As a communication medium, PROFINET uses Ethernet to link all of those components. PROFINET components can be connected within a network alongside other Ethernet protocols such as OPC UA, SNMP, MQTT, or HTTP, which can be used to complement PROFINET. 

2. What are the characteristics of PROFINET?

PROFINET offers several benefits over traditional fieldbus systems, including faster communication speeds, higher bandwidth, and increased flexibility. It also allows remote diagnostics and maintenance, which can reduce downtime and increase productivity.

  • Savings in wiring and installation costs by using distributed IO mechanisms

  • Physical layer:  copper, fiber optics, or

  • 100 Mbps, full duplex

  • Flexible topology (Line, tree, star, and ring)

  • High bandwidth

  • Large message size

  • Extensive address space

Allows coexistence with other Ethernet protocols

Figure 1. PROFINET connected devices

3. What devices do I need to set up a PROFINET network?

3.1. Is PROFINET Half-Duplex or Full-Duplex?

PROFINET is a full-duplex system, which means that data can be transmitted in both directions at the same time (Controllers and IO devices can both assume consumer and provider roles, leveraging the full duplex nature of Ethernet). Rheonics Sensors with PROFINET protocol enabled will allow 100 Mbps, full duplex communication. 

Full-duplex transmission: 

Figure 2. Full-Duplex transmission

3.2. Ethernet cable options

Recommendations for Ethernet cables that will comply with the PROFINET protocol are the following:

  • Standard Ethernet cable options

Figure 4. Flat Ethernet cable
  • Industrial Ethernet cable: Ruggedized Ethernet cables, built for the factory floor

Figure 5. Ruggedized ethernet cable [2] 
  • PROFINET cables: Industrial Ethernet cables that often come with a green jacket, and
    comply with ruggedized specifications that have been standardized by PI.

Figure 6. PROFINET ethernet cable[3]
  • Ethernet cables with cat 5, 5e, Cat 6, 6a, or Cat 7 cables, would meet the requirements based on the achievable speed of 100Mbps in 100 meters but specifications must be verified by the integrator.

3.3. Switches

The switches that should be used together with Rheonics devices should meet the minimum requirements of 100 Mbps and be capable of going full duplex.

When looking for a switch that is PROFINET compatible, the following options are the most commonly used, it is up to the user to decide which is the best for their application:

Switch Type



Unmanaged switches

  • These are inexpensive and easy to set up.

  • Great solution for those who need to connect multiple devices to the same network and don't need to configure anything.

  • No configuration interface or options

Managed switches

  • Integrated diagnostics

  • They come with a built-in configuration interface, allowing you to customize your network settings to suit your needs. 

  • They also offer advanced features like Quality of Service (QoS), VLANs, and port-level security.

  • Requires training in how to manage an ethernet network.


  •  PROFINET switches are managed switches that fulfill minimum requirements, and add PROFINET functionality.

  • Act as PROFINET devices in the network.

  • Easy diagnostics and maintenance.

  • Requires training in how to manage an ethernet network.

  • Understanding the requirements of the PROFINET network(IP address, MAC address, and station name)

4. What configuration do I need?

4.1. Addressing PROFINET networks

PROFINET Devices use a combination of Media Access Control (MAC) addressing and Internet Protocol (IP) addressing for network addressing. Each device must have a unique name, MAC address, and IP address to be identified on the network. The purpose of this combination is to enable PROFINET devices to communicate with each other and with the PROFINET controllers.

4.2. Device description files

PROFINET devices describe data using XML, which supports several languages and data structures. Since PROFINET GSD files are described in XML, a file extension of ".xml" will be used to describe the GSD files. XML structures allow the file to be validated against a PROFINET schema file to determine whether it contains valid content and structure. This ensures the file is imported correctly when imported into the engineering tool. Besides the GSD version the file adheres to (Ex: V2.3), the vendor name, the device family, and the data are also included in the file name.  

5. Does Rheonics inline viscometer and density meter support PROFINET?

Yes, all Rheonics standard sensor electronics support PROFINET communication protocol. It can be ordered prior to the shipment or can be enabled remotely. To order the PROFINET communication protocol on Rheonics sensors, check for the C9-PROFINET option in the RFQ page for the specific device you are ordering, eg. inline viscometer SRV or inline density meter SRD. More information on how to order the PROFINET communication protocol can be found in this support article: Getting Started With Profinet and Rheonics Devices


The Rheonics PROFINET instruments offer many different modules and parameters. To access these parameters, programming tools like TIA portal or Codesys can be used.  

6. How does Rheonics support PROFINET integration and development?

The PROFIBUS and PROFINET International (PI) association is one of the largest automation organization in the world and is responsible for PROFIBUS and PROFINET, the two important automation technologies. 

PI's main goals include the continuous development of PROFIBUS and PROFINET technology, know-how transfer, and investment protection. 

Rheonics is a member of PI association as a vendor of hardware, software, and PROFINET-compatible systems.  Check our membership at this link: Members

Rheonics provides detailed user manuals and technical support for integration. Our PROFINET-compatible sensors can be easily integrated into PROFINET networks thanks to all the guidelines and steps provided in our support portal. In addition, our experienced engineering team can assist with installation and configuration to ensure successful integration into your PROFINET network in a timely manner. Visit our Support portal for more information on PROFINET Protocol: Profinet


IP68 Ruggedized Cat6 Cable, Plug to Jack, E-Nickel Finish 24AWG STR CM/CMX FR-TPE BLK w/ Dust Caps, 0.5M  [2]

NBC-M12MSD/ 5,0-93B/R4AC - Cable de red - 1407501 | Phoenix Contact  [3]

How PROFINET Works? A Beginner’s Guide [4]

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