FIELDBUS Industriell datakommunikation Luca Beltramelli Email: - - PowerPoint PPT Presentation

▶
fieldbus
SMART_READER_LITE
LIVE PREVIEW

FIELDBUS Industriell datakommunikation Luca Beltramelli Email: - - PowerPoint PPT Presentation

Nov 24, 2023 121 likes •693 views

FIELDBUS Industriell datakommunikation Luca Beltramelli Email: luca.beltramelli@miun.se Mittuniversitetet References Books: Practical Industrial Data Communications by Reynders, Deon Mackay, Steve Wright, Edwin Industrial

slide-1
SLIDE 1

Mittuniversitetet

FIELDBUS

Industriell datakommunikation Luca Beltramelli Email: luca.beltramelli@miun.se

slide-2
SLIDE 2

Mittuniversitetet

References

Books:

  • Practical Industrial Data Communications

by Reynders, Deon Mackay, Steve Wright, Edwin

  • Industrial Communication Systems

by Wilamowski, Bogdan M. Irwin,

  • J. David

Industriell Datakommunikation - Fieldbus 2

slide-3
SLIDE 3

Mittuniversitetet

Program

04/05/2018

  • Seminar I:
  • Introduction to Fieldbus and Industrial Automation
  • Overview of fieldbus technologies (Part 1)

07/05/2018

  • Seminar II:
  • Overview of fieldbus technologies (Part 2)
  • Real Time Ethernet
  • WirelessHART

Industriell Datakommunikation 3

slide-4
SLIDE 4

Mittuniversitetet

Control System

Industriell Datakommunikation 4

CONTROL ALGORITHM PLANT SENSOR ACTUATOR

+

  • Control System

Feedback Reference Set

slide-5
SLIDE 5

Mittuniversitetet

Networked Control System

Industriell Datakommunikation 5

Communication Network Sensor(s) Actuator(s) Controller(s)

slide-6
SLIDE 6

Mittuniversitetet 6 Industriell Datakommunikation - Fieldbus

Fieldbuses are real-time networks for sensors and actuators. Used for the communication among sensors, actuators and controllers What is a Fieldbus?

Fieldbus

Data and Nodes Management Diagnostic and Integration Safety and Security

slide-7
SLIDE 7

Mittuniversitetet

Real Time

“A real-time system is one whose logical correctness is based on both the correctness of the outputs and their timeliness” Soft vs Hard Real Time

Industriell Datakommunikation 7

Failure to meet deadline

Catastrophic Failure Performance degradation HARD RT SOFT RT

slide-8
SLIDE 8

Mittuniversitetet 8

Office Network: TCP IP, Ethernet Plant Network: Ethernet, ControlNet

Fieldbus: FF, PROFIBUS PA, LON

Simple fieldbus or Sensor Bus: CAN, DeviceNet, SDS, ASI-bus, Interbus-S

The Automation Pyramid

Industriell Datakommunikation - Fieldbus

slide-9
SLIDE 9

Mittuniversitetet

Traditionally in industries the communication was completly analog Moving to digital communication brings many benefits:

  • Immunity to noise;
  • Less cabling;
  • Better Diagnostic;

Fieldbus replace the traditional 4 – 20 mA analog technology.

9

Fieldbuses: the beginning [mA] 20 4 Measurement Range

Industriell Datakommunikation - Fieldbus

slide-10
SLIDE 10

Mittuniversitetet 10 Industriell Datakommunikation - Fieldbus

4-20 mA vs Fieldbus

4-20 mA Fieldbus

Information Analog Digital Signal Integrity Low (EMI, Attenuation, ...) High Communication Layer Phyisical Physical, Data Link, Application Diagnostic Minimal Extensive Installation cost High Low Cost per device Low High

slide-11
SLIDE 11

Mittuniversitetet

One of the key requirements for the adoption of fieldbus is the distribuited intelligence. To access the fieldbus sensors and actuators are required to implement a communication stack. Smart Sensors:

  • Computetion capabilities;
  • Communicate in a digital way;
  • They use a communication standard (at least layers 1 and 2 of

ISO/OSI);

11

Fieldbuses: field devices

Industriell Datakommunikation - Fieldbus

slide-12
SLIDE 12

Mittuniversitetet 12

Fieldbus Evolution

From the first proprietary solutions (’80) to the actually used standard (’90) 1969

First PLC (Modicon 084)

1979

MODBUS CAN HART

1991 … 1996

Profibus FMS/DP/PA FOUNDATION fieldbus

Predecessors Proprietary solutions International Standards

Industriell Datakommunikation - Fieldbus

slide-13
SLIDE 13

Mittuniversitetet 13

Fieldbus Evolution

From the first proprietary solutions (’80) to the actually used standard (’90) 2007

Release of WirelessHART

2009

Release of ISA100.11a

2010

Introduction

  • f IO-Link

2001 … 2006

EtherCAT (2003) Eth/IP (2001) Profinet (2004) SafetyNET (2006) …

Industrial Ethernet Wireless Networks

Industriell Datakommunikation - Fieldbus

slide-14
SLIDE 14

Mittuniversitetet 14

Layer ISO/OSI Model 7 Application 6 Presentation 5 Session 4 Transport 3 Network 2 Data link 1 Physical Layer ISO/OSI Model 7 Application 2 Data link + MAC 1 Physical

OSI Model Implementation Model Fieldbus and the OSI Model

Industriell Datakommunikation - Fieldbus

slide-15
SLIDE 15

Mittuniversitetet 15 Industriell Datakommunikation - Fieldbus

Fieldbus: the applications

FIELDBUS

Factory Automation Automative Home Automation Process Automation

slide-16
SLIDE 16

Mittuniversitetet

FIELDBUS FOR AUTOMOTIVE

16

Safety

  • Redundancy, Check codes, very low data error rate

Determinism

  • Synchronized communications, TDMA

Wireless networks are considered unreliable and, up to now, are used for entertainment and extravehicular communications IEEE 802.11p for data exchange between high-speed vehicles (V2V) in the licensed ITS band of 5.9 GHz (5.85-5.925 GHz). Examples:

LIN – very simple protocol (e.g. window automation) CAN – CAN version with TDMA (e.g. ABS) FlexRay – New (BMW, Audi, Mercedes …), increases baud rate with respect to CAN (up to 10Mbytes/s) and adopts a TDMA with dynamic slots assignment.

Industriell Datakommunikation - Fieldbus

slide-17
SLIDE 17

Mittuniversitetet

FIELDBUS FOR HOME AUTOMATION

17

The low-cost is mandatory, non-invasive and mobile sensors could be the future (wireless fieldbuses)

Primary needs: low-cost, simple installation, auto-configuration There are a lot of proprietary solutions:

  • CAN – based solutions (different application layers)
  • Some emerging Ethernet-based solutions (security and costs problems)
  • EIB, EHS and Batibus converge into Konnex (KNX) (ISO/IEC 14543-

3,EN50090)

  • European Standard (Siemens, ABB, Bticino, Vimar, etc.)
  • Wired and wireless
  • LONWorks
  • Widespread in USA
  • Supported by electronic devices (Neuron Chips produced by

Toshiba, Freescale, Cypress)

Industriell Datakommunikation - Fieldbus

slide-18
SLIDE 18

Mittuniversitetet

FIELDBUS FOR PROCESS AUTOMATION

18

  • Safety is mandatory (particularly in chemical, oil, industries,…)
  • High availability (redundant system)
  • Reduce wiring (long distances) - the bus also powers the devices
  • Speed is not important
  • Cycle time are in the order of several hundreds of ms
  • Timestamp is important in case of fault (resolution ~ 100 ms)

There are only two big players:

  • PROFIBUS PA
  • FIELDBUS FOUNDATION (it has local loop control between devices)

They use the same physical layer (Manchester, powered, 31.25kbaud) but they are totally different at the data layer. Wireless can be used for non critical processes, as it reduce wiring and allow a range extension by suitable network topologies (mesh)

Industriell Datakommunikation - Fieldbus

slide-19
SLIDE 19

Mittuniversitetet

FIELDBUS FOR FACTORY AUTOMATION

19

The main goals are:

  • Fast and low-cost
  • High rejection to noise
  • Safety (e.g.protection of human operator)

Speed can be very important

  • Reduced communication times means more products, i.e.

higher gain…

  • Motion control (motor drives) need isochronous

communication More than 20 fieldbuses for Factory Automation

  • PROFIBUS DP is the most diffused but holds only the 15%
  • f the market (RS485, max 12Mbit/s)
  • DeviceNet, CANOpen, use CANbus (max 1Mbit/s) Factory

environment is hostile for wireless technology (metal, walls,…)

Industriell Datakommunikation - Fieldbus

slide-20
SLIDE 20

Mittuniversitetet

The Ideal Fieldbus: some characteristics

  • Transfers a “big number” of small data;
  • Supports real-time traffic (Upper bounded response times, ex. 1ms..1s);
  • Operates in hazardous environments (high temperature, vibrations, etc.);
  • Is robust and easy to install;
  • Has high availability (e.g. redundant architectures);
  • Has continuous supervision and diagnostic;
  • Manages long distances (100m .. 4 km);
  • Has good data transmission rate (e.g. 50 kbit/s … 5 Mbit/s);
  • Supports clock synchronization (e.g. milliseconds up to microseconds);
  • Manages non real-time traffic for maintenance and diagnosis.

20 Industriell Datakommunikation - Fieldbus

slide-21
SLIDE 21

Mittuniversitetet 21 Industriell Datakommunikation - Fieldbus

Fieldbus: the topology Fieldbus daisy chain topology Tree topology

  • Flexibility of the hardware of the measurement system
  • Cable reduction
  • Every node can share information with other nodes
  • Different delays from node to the measurement system
  • Less realiable
slide-22
SLIDE 22

Mittuniversitetet 22 Industriell Datakommunikation - Fieldbus

Fieldbus: distributed measurements In Industry to ensure good control and monitoring actions, sensor nodes should…

  • A. Be synchronized
  • Synchronization protocols
  • Delay
  • Jitter
  • B. Be identified and localized
  • Identifier for each sensor
  • Localization of moving sensor
  • C. Be qualified
  • Uncertainty measurement
  • Status report
slide-23
SLIDE 23

Mittuniversitetet 23 Industriell Datakommunikation - Fieldbus

Fieldbus: Measurement and Control Measurement

  • Data require a time reference

(timestamp) Loop Control

  • Delay must be limited

(deterministic transmission)

slide-24
SLIDE 24

Mittuniversitetet 24 Industriell Datakommunikation - Fieldbus

Fieldbus: Networked Control System (NCS) Process Controller Communication Network

Actuator Sensor Close loops in Process Automation

  • Process (temperature, humidity,…Tcycle > 1s)

Close loops in Factory Automation

  • Motion (positioning, speed, torque… Tcycle < 1 ms)
slide-25
SLIDE 25

Mittuniversitetet 25

Fieldbus: a complex scenario

Ethernet WorldFIP Profibus- PA Batibus BacNET Hart FieldBus Foundation ControlNet CANOpen Profibus-FMS DeviceNet Profibus-DP Modbus Sercos ControlFIP Seriplex CAN Profisafe M-Bus IEEE 802.11 FlexRay Ethercat EtherLink PROFInet ModBus-RTPS

AND MANY OTHERS !!!

Industriell Datakommunikation - Fieldbus

slide-26
SLIDE 26

Mittuniversitetet

HART

slide-27
SLIDE 27

Mittuniversitetet

HART (Highway Addressable Remote Transducer)

  • Developed in 1980, from 1990 is an open communication technology

for process automation.

  • Enables the transmission of digital information superimposed on

analog 4-20 mA communication.

  • The 4-20 mA is used for transmitting the analog data from sensor in

the field.

27

Layer ISO/OSI Model HART 7 Application HART Commands 6 - 3 2 Data link HART Protocol Rules 1 Physical Bell 202 (FSK modulation)

Industriell Datakommunikation - Fieldbus

slide-28
SLIDE 28

Mittuniversitetet

“Analog” for sensing information, digital for diagnostics

28

FSK modulation ‘0’ – 2200 Hz ‘1’ – 1200 Hz The average value of the Frequency Shift Keying (FSK) modulation is zero, the analog communication is unaffected by it.

Industriell Datakommunikation - Fieldbus

slide-29
SLIDE 29

Mittuniversitetet 29 Industriell Datakommunikation - Fieldbus

HART: Point to Point communication HART: Multi-point communication

slide-30
SLIDE 30

Mittuniversitetet 30

HART Telegram

Three classes of commands:

  • Universal Commands
  • Common Practice Commands;
  • Device-Specific Commands.

Industriell Datakommunikation - Fieldbus

slide-31
SLIDE 31

Mittuniversitetet

Reference

  • Official Website
  • Practical Industrial Data Communications - Ch. 18a

31 Industriell Datakommunikation - Fieldbus

slide-32
SLIDE 32

Mittuniversitetet

MODBUS

RTU and ASCII

slide-33
SLIDE 33

Mittuniversitetet

  • Application layer (Layer 7) messaging protocol
  • Developed by Modicon in 1980
  • Mainly Used in SCADA system
  • Master-slave protocol
  • Communication is initiated by the Master (Client)
  • Slaves (Server) communicate only to the Master
  • One communication at the time (Unicast or Multicast)
  • Peer-to-peer
  • UART (RS232, RS485)
  • 1 master, <248 slaves

33 Industriell Datakommunikation - Fieldbus

slide-34
SLIDE 34

Mittuniversitetet

Communication based around a Query-Response cycle The function code in the query tells the addressed slave device the action to perform. (ex. read Input Registers, Force Single Coil, Read Coil Status ) Modbus message Frame

34 Industriell Datakommunikation - Fieldbus

slide-35
SLIDE 35

Mittuniversitetet

  • Two serial transmission mode (no coexistence):
  • ASCII mode
  • 1 byte -> 2 char (0-9, A-F)
  • Error Check -> LRC
  • Bits per Byte:
  • RTU mode
  • 1byte -> 8 bit (0 … 255)
  • Error Check -> CRC
  • Bits per Byte:

35 Industriell Datakommunikation - Fieldbus

slide-36
SLIDE 36

Mittuniversitetet

Reference

  • Modbus over serial line
  • Modbus Specifications
  • Official Website
  • Practical Industrial Data Communications - Ch. 8a

36 Industriell Datakommunikation - Fieldbus

slide-37
SLIDE 37

Mittuniversitetet

CANbus

slide-38
SLIDE 38

Mittuniversitetet

Controller Area Network (CAN) Developed in ’85 by Bosch for automotive

  • Random access bus (32 users, 1Mbps @ 40m)
  • CSMA/CA
  • Multi-master bus
  • Asynchronous Serial Bus
  • 4 frames: DATA (data exchange), REMOTE (request to send

data), ERROR (error signaling), OVERLOAD (temporary unavailable)

38 Industriell Datakommunikation - Fieldbus

slide-39
SLIDE 39

Mittuniversitetet

The CAN standard includes:

  • Physical layer
  • Data-link layer
  • Message types
  • Arbitration rules for bus access
  • Methods for fault detection and fault confinement

39 Industriell Datakommunikation - Fieldbus

slide-40
SLIDE 40

Mittuniversitetet

Phy layer

  • Maximum bitrate 1Mbps.
  • The bitrate depend on the bus length.
  • The bitrate is limited to sense the collision between distant nodes.
  • Twisted pair cable, differential transmission

40 Industriell Datakommunikation - Fieldbus

slide-41
SLIDE 41

Mittuniversitetet 41 Industriell Datakommunikation - Fieldbus

  • Bit Coding: NRZ (does not ensure enough edges for synchronization)
  • Bit Stuffing is Required
  • “open-collector like”, that is “0” level wins
  • Automatic bus release if collision occurs and retransmission

(CA N, …) (Profibus , Etherne t …)

slide-42
SLIDE 42

Mittuniversitetet

Higher Layer Protocols

  • CANOPEN
  • DEVICENET
  • CAN Kingdom
  • …

The Arbitration Field contains a 11-bit (CAN 2.0 A) or 29-bit (CAN 2.0 B) identifier for the data. Data with higher priority have the MSBs at ´0´ and win the arbitration.

42 Industriell Datakommunikation - Fieldbus

slide-43
SLIDE 43

Mittuniversitetet

Reference

  • Official Website
  • Industrial Communication Systems - Ch. 31

43 Industriell Datakommunikation - Fieldbus

slide-44
SLIDE 44

Mittuniversitetet

PROFIBUS

slide-45
SLIDE 45

Mittuniversitetet

PROFIBUS (Process Field Bus) Three versions of the standard:

  • Profibus FMS (1991)
  • PLC-PLC, PLC-SCADA, PLC-Field device (complex, obsolete)
  • Profibus DP (1994)
  • Simpler than FMS, normally 1 master (PLC), several slaves (field

devices)

  • Market leader
  • Profibus PA (1995)
  • Different and more robust physical layer (IEC 61158-2)

45 Industriell Datakommunikation - Fieldbus

slide-46
SLIDE 46

Mittuniversitetet

Layer ISO/OSI Model FMS DP PA User FMS Devices Profiles DP - Profiles PA - Profiles DP - Acyclic Part DP - Cyclic Part 7 Application Fieldbus Message Specification (FMS) 6 - 3 2 Data link (Fieldbus Data Link (FDL) IEC Interface 1 Physical RS-485 Fiber Optic IEC 61158-2 (Manchester Encoded Power Bus)

46 Industriell Datakommunikation - Fieldbus

slide-47
SLIDE 47

Mittuniversitetet

Profibus: the actors

  • DPM1 (Master Class 1):central controller which exchanges data

with the connected I/O devices (slaves).

  • Determines the bitrate.
  • Handles the Token;
  • Several class1 masters are permitted, typical devices are

PLC, PC.

  • DPM2 (Master Class 2): diagnostic and startup tool, typically a

configuration tool, can control one slave at a time.

  • Slave: passive station which acknowledges messages or

answers per request

47 Industriell Datakommunikation - Fieldbus

slide-48
SLIDE 48

Mittuniversitetet

  • At least one master is mandatory.
  • Profibus networks allow for multiple masters.
  • In total 127 stations can be addressed

48 Industriell Datakommunikation - Fieldbus

slide-49
SLIDE 49

Mittuniversitetet

The slave is in one of four possible states:

  • Power_ON / Reset
  • Wait for Parameters
  • Wait for Configuration
  • Data Exchange

Cyclic data exchange between a Class 1 master and a DP slave can only take place if the DP slave is in the data-exchange state (DXCHG).

Master-Slave Communication

DP Slave State Machine The master with the token can make use of communications to address any other station (masters and slaves).

49 Industriell Datakommunikation - Fieldbus

slide-50
SLIDE 50

Mittuniversitetet

Master-Master Communication

Using a DP-DP gateway:

  • combination of two mono master

systems;

  • simple data exchange between the

two masters up to 244 byte. Via the master-slave combination:

  • whenever one master has the token the
  • ther PLC can be a slave to this

master.

50 Industriell Datakommunikation - Fieldbus

slide-51
SLIDE 51

Mittuniversitetet

Profibus transmission media

  • RS-485
  • Twisted cable
  • Baudrate 9.6 kbit/s to 12 Mbit/s
  • Maximum 32 devices
  • Distance can be extended by means of repeaters
  • 12 Mbit/s @ 100 m
  • 187.5 kbit/s @ 1000 m
  • Fiber Optic
  • Single and Multi Mode
  • Baudrate 9.6 kbit/s to 12 Mbit/s
  • Distance can be extended by means of repeater to 100 km
  • MBP-IS
  • Twisted cable
  • Fixed Baudrate of 31.25 kbit/s
  • Maximum distance 1900 m
  • Between 10 and 32 devices per segments
  • Power Supply directly from the bus

51 Industriell Datakommunikation - Fieldbus

slide-52
SLIDE 52

Mittuniversitetet

Fieldbus Data Link

  • 4 types of frames
  • Identified by the value of the first byte (Start Delimiter)

SYN: 33 bits at 1

SD1 10h 01101000 SD2 68h 10100010 SD3 A2h 00010000 SD4 DCh 11011100

Hamming Distance equals to 4

Note: SD3 practically unused

52 Industriell Datakommunikation - Fieldbus

slide-53
SLIDE 53

Mittuniversitetet

Message SD2 (data exchange)

SD2 Start Delimiter (68H) LE Information length (from 4 to 249) LEr Information length repeated (Hamming distance = 4) DA Destination address SA Source address FC Frame Control DATA UNIT Data field (max length 246) FCS Frame Check Sequence ED End Delimiter (16H) L Information length (L = from 4 to 249)

53 Industriell Datakommunikation - Fieldbus

slide-54
SLIDE 54

Mittuniversitetet

Message SD1 (data request or Ack) Message SD4 (token transfer) Message SC (short Ack)

SD4 Start Delimiter (DCH) DA Destination address SA Source address SC Short acknowledgment (E5H) SD1 Start Delimiter (10H) DA Destination address SA Source address FC Frame Control FCS Frame Check Sequence ED End Delimiter (16H) L Information length (L = 3)

54 Industriell Datakommunikation - Fieldbus

slide-55
SLIDE 55

Mittuniversitetet

GSD file (General Station Description)

  • each slave or master class 1 device on PROFIBUS needs to have a

device description file, the characteristic of each PROFIBUS device is described in the GSD-File;

  • the GSD-file contains all device specific parameters e.g.:
  • Supported Baudrate
  • Supported Message Length
  • Number of input / output data
  • Meaning of diagnostic messages
  • Options for modular devices e.g. which are available
  • text file (ASCII-format);
  • each configuration tool relates to the GSD information.

57 Industriell Datakommunikation - Fieldbus