PROFIBUS Siemens

Обзор



What is PROFIBUS?

PROFIBUS is the most successful open fieldbus used for automation technology which can be used for a wide range of applications. Standardization according to IEC 61158/EN 50170 secures your investments for the future.

PROFIBUS defines the technical and functional features of a serial fieldbus system, with which the distributed field automation devices in the lower area (sensor/actuator level) can be networked up to the mid performance range (cell level).

The requirements of users for an open, non-proprietary communication system have resulted in the specification and standardization of the PROFIBUS protocol.

Multi-vendor installations

Using the conformity and interoperability test performed by the test laboratories authorized from PROFIBUS & PROFINET International (PI) and the certification of the devices by PI, users have the security that the quality and functionality is guaranteed, even in multi-vendor installations.

PROFIBUS versions

PROFIBUS FMS (Fieldbus Message Specification)
The universal solution for communication tasks on the field and cell level of the industrial communication hierarchy.

PROFIBUS PA (Process Automation)
The version for applications in process automation. PROFIBUS PA uses intrinsically secure data transfer technology defined in IEC 61158-2.

PROFIBUS DP (Distributed Peripherals)
This version, which is optimized for speed, is tailored especially for the communication of automation systems with distributed I/O stations and drives. The outstanding features of PROFIBUS DP are

  • very short response times
  • high interference immunity

PROFIBUS DP replaces cost-intensive parallel signal transmission with 24 V and the measured value transmission with 0 mA or 4 mA to 20 mA technology.

PROFIBUS and SINAMICS

SINAMICS uses the PROFIBUS protocol PROFIBUS DP.

Дизайн



Bus nodes

PROFIBUS DP distinguishes between two different master classes and one slave class:

DP master Class 1

For PROFIBUS DP, DP master Class 1 is the central component. In a defined message cycle that always repeats itself, the central master station exchanges information with distributed stations (DP slaves).

DP master Class 2

When commissioning, to configure the DP system, for diagnostics or to operate the plant or system in operation, devices of this type are used (programming, configuring or operator control devices). A DP master Class 2 can be used, for example, to read the input, output, diagnostic and configuration data of the slaves.

DP slave

A DP slave is an I/O device, which receives output information or setpoints from the DP master, and as response, returns input information, measured values and actual values to the DP master. A DP slave never sends data automatically, but only when requested by the DP master. The quantity of input and output information depends on the device, and for each DP slave in each send direction can be a maximum of 244 bytes.

Функции



Functions on PROFIBUS DP

The functional scope can differ between DP masters and DP slaves. The functional scope is different for DP-V0, DP-V1 and DP-V2.

DP-V0

The DP master functions (DP-V0) comprise the functions "Configuration", "Parameter assignment", "Read diagnostic data" as well as "Cyclic reading of input data/actual values" and "Writing output data/setpoints".

DP-V1

The additional DP function expansions (DP-V1) make it possible to perform acyclic read and write functions as well as processing cyclic data communication. This type of slave must be supplied with extensive parameterization data during start-up and during normal operation. These acyclically transferred parameterization data are only rarely changed in comparison to the cyclic setpoints, actual values, and measured values, and are transferred at lower priority in parallel with the cyclic high-speed user data transfer. Detailed diagnostic information can be transferred in the same way.

DP-V2

The extended DP master functions (DP-V2) mainly comprise functions for isochronous operation and direct data exchange between DP slaves.

Isochronous mode is implemented by means of a signal with a constant bus cycle for the bus system. This cyclic, equidistant cycle is sent by the DP master to all bus nodes in the form of a Global Control Telegram. Master and slaves can then synchronize their applications with this signal. The jitter of the clock signal from cycle to cycle is less than 1 µs.

The "publisher/subscriber model" is used to implement slave-to-slave communication. Slaves declared as publishers make their input data/actual values and measured values available to other slaves, the subscribers, for reading. This is performed by sending the response frame to the master as a broadcast. Slave-toslave communication is therefore a cyclic process.

SINAMICS and PROFIBUS DP

The SINAMICS S120 drive system can operate only as a DP slave and supports all communication functions, i.e. DP‑V0, DP‑V1 and DP‑V2.

SINUMERIK and PROFIBUS DP

The SINUMERIK 840D sl control system functions as the DP master for drive axes and supports all DP-V0, DP-V1 and DP-V2 communication functions. SINAMICS S120 drives as well as distributed hydraulic axes can be linked as slaves to these systems. The decentralized hydraulic axes can only be used with isochronous PROFIBUS.