What is Profinet?
Profinet is an industrial communication protocol developed by the Profibus International consortium (PI) since 2002, and it is an international standard compliant with the IEC 61158.
Profinet, born to be the heir of Profibus it based over Ethernet and Its main aims are the project and plant commissioning costs reduction through an easy integration between the automation Ethernet-based devices and the Siemens devices.
Nowadays, referring to data communication, PROFINET groups under its name two families of protocols both based on Ethernet, Profinet CBA and Profinet IO.
Proﬁnet IO (PNIO) is designed to give field devices an Ethernet interface and to ensure deterministic and real-time performance.
Profinet IO PNIO’s aim is data trasmission by using simple communication structures and equipment while meeting pre-established performance.
With the dual aim of exploiting the know-how in fieldbus sector and protecting previous investments, PROFINET IO has incorporated concepts such as modular architecture and field devices programming, taking them directly from PROFIBUS.
To achieve the high performance required in data exchange, some innovative elements were needed:
- priorities for data exchange have been set;
- differentiated access by several control systems for the same field device;
- functionalities description in a GSD file of the individual field device;
- PROFIBUS DP model extension: the Master-Slave access methodology (of PROFIBUS DP) has been converted to the Provider-Consumer model, where the manufacturer is defined as the data generator while the consumer receives and uses the data when establishing the connection with the manufacturer. Moreover, communication occurs on a single transmission medium.
A network with no devices dedicated to the access control to the bus is called Producer/Consumer type.
Any node can temporarily acquire the bus control and start a transmission (Producer interface), the other nodes, at this point, will activate in reception (Consumer interfaces).
PROFINET IO specifies four types of devices:
IO-Controller: controller device with the automation program; it has the control of the distributed process of one or more field devices and it is responsible for the configuration and parameterization of the associated devices. It receives data and alarms and processes them within the user program. It represents an intelligent central station, like a PLC.
IO-Device: remote fieldbus device, which is assigned to an IO-Controller.
It is configured by an IO-Controller or an IO-Supervisor and cyclically transmits its process data to the controller. It also informs an IO-Controller about diagnostic or alarm conditions.
IO-Supervisor: programming device/PC with configuration and diagnostic functions.
It also can exchange data with IO-Controller and IO-Device; has temporary access to field devices during the communication process.
IO-parameter-server: devices used for the exchange of configuration data relevant for applications with IO-Device.
The traffic generated by IO-Supervisor and IO-Parameter-Server is typically offline, therefore no real-time performance are required.
During operation, peripheral devices (IO-Devices) transfer input information to the controller; it processes and transfers output information to peripheral devices.
Instead, the data exchange between IO-Controller and IO-Device is connected to the automation task in progress and, therefore, has critical time requirements.
The PROFINET IO protocol implement the transfer of three types of data:
CYCLICAL TRANSFER OF IO’S CRITICAL DATA: these data are stored in the controller’s IO addressing area; they are cyclical input and output data, sent to the real-time channel. The IO data shall be transmitted over pre-established time cycles, whose updating frequency may be changed for each device.
ACYCLIC TRANSFER OF ALARMS: it happens on the real-time channel; there’s also the possibility to assign a priority to the alarms;
ACYCLIC TRANSFER OF NON-CRITICAL DATA: this is parameterization, configuration, reading of diagnostic information that is transferred through standard channels based on UDP/IP.
In factory and process automation, timely and deterministic data transmission is required.
For cyclical IO data exchange (time-critical) between controllers and field devices, PROFINET IO does not use TCP/IP, but a real-time communication (RT) or real-time isochronous communication (IRT) with a tighter traffic time schedule obtained by synchronization between the network level and the software application that manages the data (<1ms).
Both RT and IRT communication procedures are standardized in the international standard IEC 61158.
What is PROFINET IO RT?
PROFINET IO RT meets most of the timing requirements of industrial automation. Most PROFINET networks can rely exclusively on PROFINET RT for all cyclical data exchanges.
The applications field of PROFINET IO RT are:
● Time-critical applications in factory automation
● Applications in process automation systems.
- Profinet communication class IO RT (Class 1): The implemented communication class can realize cycles of a few milliseconds (typically 1-64 ms) and limited variability (15%). It is based on the 802.1Q Ethernet standard where data is transmitted via priority Ethernet telegrams (RTdata has priority 6): this ensures the determinism required by automation. Standard Ethernet hardware it’s enough for the implementation.
Profinet and the drives: PROFIdrive
PROFIdrive it is a standard that defines the rules and the control modalities of motor drives and master controllers connected through PROFINET and PROFIBUS
FEATURES AND ADVANTAGES OF EVER ELETTRONICA DRIVES FOR STEPPER MOTORS AND BRUSHLESS MOTORS
The feature and the advantages of Ever Elettronica drives for stepper motors and brushless motors are:
- PROFINET communication developed with SIEMENS ASIC ERTEC 200P
Siemens, as an active member of PI, has been involved in the development of PROFINET from the beginning. Siemens technological components, so, benefit from a consolidated the know-how of many years of development work and successes, and has already been proven in the field in countless products.
The ERTEC 200P (Enhanced Real-Time Controller) guarantees all the performance standards required by the most stringent and performing PROFINET IRT communication.
ERTEC 200P is designed for cycle times of only 31.25μs. With its fast ARM 9 CPU and integrated IRT switch, field devices with the most demanding performance requirements are possible.
- IRT switch (dual Ethernet ports)
All our drives for stepper motors and brushless motors are equipped with a 2-ports IRT switch to allow you to divide the network into different segments.
- PROFINET IO RT Class 1 (CC-B)
- Data exchange (Real Time) for applications with cycle time up to 4 ms;
- Alarm and diagnostic data;
- Support for network topology;
- Simple Network Management Protocol (SNMP) network diagnosis.
- Cyclic data exchange: 64 bytes INPUT(on Slot1) and 64 bytes OUTPUT (on Slot2) between the IO-controller (PLC) and the drive for stepper motors and brushless motors (IO-Device). Particularly:
- 16 bytes (I/O) are fixed mapped;
- 40 bytes (I/O) can be mapped according to the required functions by using e3PLC;
- 8 bytes (I/O) are used for the drive R/W objects in accordance with the Canopen SDO service;
- Digital I/O (24vdc) and analogue drive inputs are available as I/O points distributed over the Profinet network.
- Ready-to-use mapping of 64 IO bytes
The 64 bytes of input and 64 bytes of output have already been configured in the drive for stepper motors and brushless motors to map the most common parameters and drives and motors registers configuration, movement commands and status variables (General Purpose Profinet App 0144 free application).
Bytes can still be remapped by using the IDE e3PLc environment programming (easy, fast and intuitive proprietary Ever Elettronica Integrated Design Environment) which allows the implementation of complex programs without no programming languages knowledge required.
- Ever_profinet_fb_v1.01 library for STEP 7 TIA Portal V15 (Siemens)
With this 4-Function Block (FB) library, you can quickly set data exchange, drives settings, stepper motors and brushless motors parameters and movement controls in the centralized TIA Portal design environment.
-Diagnostic and configuration tool of the drives for stepper motors and brushless motors on PC via Modbus TCP over Profinet
You can run all the tools on Pcs provided by Ever Elettronica by using the same Profinet network, through Modbus TCP protocol (port 502) without using the SCI serial service.
Ever Elettronica produces a wide range of drives for stepper motors and brushless motors, offering complete motion control solutions.