...is the world's most successful fieldbus with 67.4 million devices installed by the end of 2022!
Utilizing a single, standardized, application-independent communication protocol, PROFIBUS supports fieldbus solutions both in factory and process automation as well as in motion control and safety-related tasks.
PROFIBUS is standardized in IEC 61158 – the foundation has therefore been laid for interoperability and compatibility. Furthermore the PROFIBUS PA profile allows the smooth cooperative working of process devices on the bus. The current PROFIBUS PA version V3.02 includes many functions, which make the handling of field devices even easier, e.g. in case of a device exchange.
When a field device is exchanged the new device automatically takes over the role of the predecessor device – therefore a device exchange can be carried out easily and without interruption of the system operation.
This automatic adaption is also possible with devices of different generations.
This means that standardization offers more flexibility and no limitation in your choice of supplier. Indeed, in the meanwhile there is a vast range of devices available that can be combined in almost any way. A focus on only one manufacturer is no longer given.
Even replacing devices later on is absolutely easy and with PROFIBUS new devices are always backward-compatible.
Consistent and application oriented
PROFIBUS is the fieldbus-based automation standard of PROFIBUS & PROFINET International (PI). Via a single bus cable, PROFIBUS links controller or control systems with decentralized field devices (sensors and actuators) on the field level and also enables consistent data exchange with higher ranking communication systems. Consistency of PROFIBUS is enabled by utilizing a single, standardized, application-independent communication protocol (named PROFIBUS DP), which, without any difference, supports fieldbus solutions both in factory and process automation as well as in motion control and safety-related tasks.
PROFIBUS is modularely structured as building block (fig. 1) with the communication protocol as core component. This is combined with application-specific modules for transmission, application (“Applica-tion profiles”) and engineering to form complete PPROFIBUS solutions for specific market segments (industry sectors), as shown in fig. 2.
To ensure correct interaction between the numerous devices of an automation solution, the basic de-vice functions and services must match in regard to communication, functionality and industry sector solutions. This uniformity is achieved by means of "application profiles" which refer to device families or special industry sector requirements, e.g. process automation (PA Devices), Motion Control (PROFIdrive) or integration of HART devices (HART on PROFIBUS).
The "hybrid" factor of PROFIBUS
PROFIBUS covers factory and process automation with the same consistent communication protocol and therefore enables mixed (hybrid) applications, which are often seen in the pharmaceutical or food and beverage industries or in water and waste water applications. Here, continuously running processes, e.g. mixing or drying, are typically combined with discrete functions such as identifying, conveying or packing (fig. 3). Here, the common communication protocol PROFIBUS DP combined with specific application profiles provides a powerful advantage: both process and factory automation networks can be connected to the same single cable. Other buses focus on either process or discrete markets so they always have to use a second fieldbus, which means extra expense for cabling, equipment, skills, maintenance and support. PROFIBUS is alone in delivering a single solu-tion for both sectors.
Fig. 3: PROFIBUS hybrid automation
In figure 4, PROFIBUS DP is in the central position and carries communication data between a controller and field devices, preferably in Factory Automation (FA). Downwards, a PROFIBUS PA string is connected through a coupler or linking device to enable typical process automation (PA) applications, e.g. in a hazardous enviroments. Upwards, the controller is connected to PROFINET as system bus and interface to MES and ERP levels. PA segments can also be connected directly to PROFINET using proxy technology.
Fig. 4: Unreached consistency of PROFIBUS
The value propostion of PROFIBUS
is commandingly high, enabling it to cut costs and improve business results across the life cycle of a plant. It does this in many ways:
- At the engineering stage it simplifies plant design, eliminates hard wiring and requires less hardware, leading to faster commissioning and lowered costs.
- It also supports better diagnostics, so commissioning is much faster.
- It helps achieve better productivity and higher product quality through the delivery of better and more timely data to operations and management staff.
- It supports advanced asset management strategies that allow plants and equipment to be better managed and maintained.
PROFIBUS Dialogues - Life Cycle Management
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PROFIBUS Dialogues - Life Cycle Management / I & M Functionality (EN)
Easy to use and universal
- PROFIBUS is based on standards and modularity. User benefits are ease of use and flexibility. The single communication protocol enables fully integated solutions of continuous as well as discrete and safety-related processes to run on the same bus.
- This eliminates the need for separate systems and allows hybrid automation.
- In process automation, the device profile ensures compatible device behavior on the bus enabling the user to choose any “profile device” of his choice.
- Diagnostic data display is sorted according to the NAMUR NE 107 standard:
- The operator can detect the status reliably and react appropriately.
Efficient and productive
- Efficient industrial processes require high machine and plant availability. The integrated redundancy of PROFIBUS is unreached when it comes to uninterrupted operation.
- As important are the extensive diagnostic messages sent from bus, field devices and process to inform about the current status and to enable timely, status-based intervention.
- The result is higher availability combined with reduced maintenance costs.
- PROFIBUS is optimized for distributed I/O applications. Up to 126 I/O devices can be connected to a PROFIBUS DP cable. Since each I/O device can handle hundreds of connection points, this provides a very large number of connection possibilities for a single controller.
- PROFIBUS enables proactive management over the life cycle of a plant. When more advanced device technology is to be deployed, plant operation must not be interrupted when installing the new devices. The solution: starting in profile for PA Devices version 3.02, new devices can temporarily adopt the functionality of predecessor versions. In this way plant operation is not interrupted, and the additional functions can be integrated during the next maintenance phase. The ability to take advantage of device innovations is assured, and the inventory of replacement devices is significantly reduced
- PROFIBUS is known for its high degree of innovation: User requests are gathered and implemented rapidly. PA Profile 3.02 with its NAMUR-compliant diagnostics concept is an example.
- Other examples are the high-effective redundancy concepts and the proxy technology, enabling the user to PROFIBUS systems to the Ethernet level (PROFINET).
- Existing plants can be modernized and expanded at any time with PROFIBUS:
- HART technology is integrated easily, safety-related and drive tasks are solved with PROFIsafe and PROFIdrive, respectively.
- PROFIBUS supports advanced asset management strategies that allow plants and equipment to be better managed and maintained.
Implementing transmission interfaces:
Without power supply from the bus cable
For field devices which do not draw the required power from the bus, the standard copper-based RS485 interface can be implemented. This provides greater flexibility when using the field device, because it can be connected to PROFIBUS DP without a segment coupler or link. Data rates from 9.6 KBit/s to 12 MBit/s are supported. RS485 modules are available from various manufacturers including an intrinsically safe version RS485-IS.
With power supply from the bus cable
In many applications bus-powering of the field device is required. Here, the MBP (Manchester Coded Bus Powered) transmission technology is available which provides a typical supply current of 10 - 15 mA on the bus cable. This has to supply the entire device, including the bus connection and the measurement electronics. Special modem chips are available for these requirements. These modems draw the required operating energy from the MBP bus connection and make it available as supply voltage to the other electronic components of the device and convert the digital signals of the connected protocol chip to the bus signal of the MBP connection that is modulated to the energy supply.
Implementing the communication protocol
A broad spectrum of base technology components and development tools (PROFIBUS ASICs, PROFIBUS stacks, bus monitors, test tools and commissioning tools) and services are available for implementation of the PROFIBUS protocol. Additionally, PI competence Center and many suppliers offer support in this regard. An overview of this is found in the product catalog from PI. When implementing a PROFIBUS interface, it must be considered that the device behavior is determined by the PROFIBUS protocol and the implemented application. For this reason, the entire field device is tested during a certification test along with an eventual pretesting of the used base technology.
For small to medium quantities of devices, PROFIBUS interface modules are suitable which are available in a wide variety of versions on the market. They can be attached to the main PCB of the device as a supplementary module. They implement the full bus protocol and offer an easy-to-use user interface for each application.
For larger quantities of devices, the use of protocol chips with or without additional microcontroller is the best solution with the following alternatives:
- Single chips, where all PROFIBUS protocol functions are integrated on the chip and which do not require a separate microcontroller (fig. 1, left). This is a hardware-only solution with a fixed functional scope. This solution using single chip ASICs is recommendable for basic IO devices. Only the components for the bus connection are required externally.
- Chips, which implement smaller or larger portions of the protocol, are combined with an additional microcontroller and firmware offered for the chip (fig. 1, center) to provide the full implementation of the PROFIBUS protocol. With this form of implementation, for instance, the essential layer-2 portions of the PROFIBUS protocol are implemented with a communication module.
- Protocol chips which already include a micro-controller in the communication module. In conjunction with firmware offered for the chip (fig. 1, right), the application communicates via an easy-to-use user interface. This soltion is used for highly time-critical applications, because the protocol chips with an integrated microcontroller already handles the entire PROFIBUS protocol autonomously and an externally-connected microcontroller can then be used entirely for the application.
Fig. 1:Different protocol chip solutions
Often the PROFIBUS chip and the supplemental protocol sofware (stack) come from different sources which increases the number of possible solutions and shows the the openness and multi-vendor capability of PROFIBUS. Pure software solutions can seldom be found on the market.
Implementing application profiles
The interpretation of data in a field device is handled by the user. User profiles represent the links between the PROFIBUS protocol and the actual application in a field device. The data formats, data access methods, parameterization and cyclical and acyclical communication diagnostics defined in the profile descriptions are implemented in software, which is often handled by the device manufacturers or technology suppliers.