Protocolli E Bus Di Campo Per L'industria

Protocolli e bus di campo per l’industria: Ethernet Deterministica, PROFIBUS ed altri Roberto Isernia – Technical Marketing Leader

Agenda • • • • •

Fieldbus Protocols Why Ethernet-Based Protocols? Overview of Ethernet-Based Industrial Protocols Adding Deterministic I/O to NI PACs PROFIBUS and NI Platform

A jungle of different standards

Why Ethernet-Based Protocols? Modbus

Modbus TCP/IP

DeviceNet

Ethernet/IP

CANopen

EtherCAT

PROFIBUS

PROFINET

Traditional Industrial Protocols

Ethernet Physical Layer

4

Industrial Ethernet Adoption • Total market $630 M • Ethernet really means: – Ethernet/IP – PROFINET – Modbus TCP/IP

Source: VDC 2006

Expected Trends in Type of Wireline Infrastructure Networks being used in Industrial Facilities

Ethernet-Based Industrial Protocols • • • •

Modbus TCP/IP EtherCAT Ethernet/IP PROFINET

Similarities • Reuse OSI model layers 1 and 2 – What about the other 5 layers?

• Define master (scanner) and slave (adapter) devices • Address 1 or more target applications – Non Real Time – Real Time – Hard Real Time

Application Targets • Non Real Time – Uses standard TCP/IP or UDP/IP – Application: PLC to HMI or PLC to SCADA

• Real Time – Provides added determinism with COTS hardware – Application: Control data

• Hard Real Time – Adds specific hardware to deliver determinism – Application: Distributed motion

Where Protocols Fit?

EtherCAT

PROFINET (IRT)** Ethernet/IP CIP Sync PROFINET (RT)**

Ethernet/IP

Modbus TCP/IP PROFINET (NRT)*

Ethernet/IP

**Also PROFINET I/O *Also PROFINET CBA

EtherCAT Overview • EtherCAT – Ethernet Control Automation Technology – Managed EtherCAT Technology Group (ETG) – Open and based on standards such as IEC 61158

• Advantages – Hard real-time industrial protocol – Extremely efficient and straightforward communication

• Disadvantages – Addresses only hard real time (?) – Not designed for standard TCP/IP packets and EtherCAT packets

Functional Principle: Ethernet On-the-Fly Fast Train Analogy • “Train” (Ethernet frame) does not stop • Even when watching the “train” through a narrow window one sees the entire train • “Car” (subtelegram) has variable length • One can “extract” or “insert” single “person” (bits) or entire “groups” – even multiple groups per train

NI Scan Engine

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HRT: Determinism and Performance Organization

Response Time (ms) EtherCAT ~ 0.1 Sercos III < 0.5 PROFINET IRT <1 Ethernet Powerlink <1 Ethernet/IP ~1 Table 1. Real-Time Comparison of the Various Real-Time Methods Standards-Based Real-Time Ethernet Now Off-the-Shelf by Klaus Zwerina

Jitter (us) < 0.1 < 0.1 <1 <1 <1

Data Rate (Mb/s) 100 100 100 100 100

NI System with Deterministic Distributed I/O Host Computer NI PXI System NI PXI System with Ethernet Interface with Ethernet Interface

(TCP/IP) (TCP/IP)

NI cRIO-9074 NI cRIO-9074 (EtherCAT) (EtherCAT)

NI 9144 NI 9144

LabVIEW Modbus Options NI Modbus VIs

Modbus I/O Server

Communication from NI LabVIEW to ControlLogix PLCs EtherNet/IP

Available for download from NI Labs at ni.com/labs

EtherNet/IP VIs for LabVIEW • Provides VIs for communication to “Logix” PLC tags – Directly read and write tags on Allen-Bradley ControlLogix and CompactLogix PLCs

• Runs on LabVIEW for Windows and LabVIEW Real-Time OSs (Phar Lap and VxWorks) • Explicit messaging • Good for low numbers of tags

ni.com/pac/i ni.com/labs