Agenda Communication in Automation · 2 RS-232 • RS-232 is a standard for serial communication RS is short for Recommended Standard. • This standard describes th e signals between

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Communication in Automation

• Thomas Gillblad

• LtH 8 maj 2020

• Lecture starts at 08.15

Agenda

• Different industrial networks• Technology overview• Practical considerations• Examples and factory wide networks

ISO model

• Different types of networks can be described with the same model

Physical layer

• The Physical Layer protocol defines the electrical/optical and physical characteristics of connections, such as bit rates, contention mechanisms, signal rise times, and encoding schemes, as well as how to activate/deactivate transmission on a given medium.

• Exempel: RS-232, RS-422, RS-485, RJ-45, Bluetooth/BLE, NFC

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RS-232• RS-232 is a standard for serial communication RS is

short for Recommended Standard.• This standard describes the signals between computer

(DTE) and modem (DCE).• The standard was developed in the 1980s and uses 9

pin (D9) and 25 pin contacts (D25) • RS-232 defines the voltages +3 to +12 V as logic 0

and -3 to -12 V as a logic 1.• Normally 3, 5, 8 or 9 wires are used. Three are used to

send data (TxD), receive data (RxD) and for common ground (SG). Two more wires (RTS and CTS) are used for data signalling; that data shall be sent ( DTE ) and is ready to receive ( DCE ) You do not have to send data control characters. The remaining 4 wires are used to indicate communication readiness (DTR and DSR), established line contact (DCD) and one signal for telephone signal (RI).

• If two computers are to talk directly a cable with crossed wires is necessary (a null modem cable).

RS-485

• RS-485 enables the configuration of inexpensive local networks and multidrop communications links. It offers data transmission speeds of up to 35 MBIT/s up to 10 m and 100 kbit/s at 1200 m. It is a differential balanced line over twisted pair (like RS-422), it can span relatively large distances (up to 1,200 m). A rule of thumb is that the speed in bit/s multiplied by the length in meters should not exceed 108. Thus a 50 meter cable should not signal faster than 2 Mbit/s

• 4 wire can be full duplex, single wire half duplex • Examples are Modbus, Profibus

RS-485 Buses• TCP/IP inexpensive, widely used, not deterministic• Profibus safe, established, not so inexpensive• ProfiNet also accepted, real time version not common• CAN bus : you use it more than you think!• ASI and EtherCAT bus grows all the time• IP but not TCP: Deterministic tinkering of 802.3 grows by

the minute

• Many old ones: Interbus S (star net), DeviceNet, Echelon• About 100 around, number stable over time. IIoT brings

new types

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Modbus

• Modbus is a serial communications protocol originally published by Modicon (now Schneider Electric) in 1979 for use with its (PLCs). Simple and robust, it has since become a widely used communication protocol, and it is now a commonly available means of connecting industrial devices ; 4 wire can be full duplex, single wire half duplex

• Modbus has two common forms, Modbus serial and Modbus TCP• The data format is either ASCII or RTU (Remote Terminal Unit).• Modbus is a polled, Master/Slave protocol, with up to 3 masters and

240 slaves (total number of adresses 247)• Modbus has a limited number of data types (IEEE floating point, 32

bit integer, 8 bit data, single bits, multipliers (counters)

Modbus

• Modbus: the protocol standardises connection plus data format • www.modbus.org

Data link layer

• The Data Link Layer provides delivery of frames across a single physical connection, and provides framing, error detection, and (potentially) retransmission of errored frames.. In practice this layer normally discards errorneous frames but does not request retransmission.

• Exempel: Ethernet, 802.3, HDLC, PPP.

Problem, same media but different protocols

7 Protocol A Protocol B

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5

X4 TCP TCP

3 IP IP

2 CSMA/CD CSMA/CD

Ethernet Ethernet1

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Common Industrial protocols

• Many common protocols uses layers 1-4 + 7

Network FeatureProfibus DP • DP 12 Mb/s, Master and/or slave,

• 1 or 2 channels• DP V0 & V1 (acyclic communication)• FDT/DTM compatible • Card format• Product names

DeviceNet • DeviceNet Master/Scanner slave, • 1 or 2 channels• Card format• Product names

CanOpen • CanOpen Master/Scanner• 1 or 2 channels• NIC format• Product names

Schneider Ethernet Modbus IO

• Client/Server, 1 channel, 100 Mb/s• NIC format• Product names

Rockwell EtherNet/IP for IOs

• Master Scanner and Slave, 100 Mb/s• NIC format• Product names

Network layer

• The Network Layer is responsible for logical addressing of end-points, path determination, and routing (forwarding). It provides delivery of packets between the two end points, and for the addressing, etc. associated with this. Both connectionless and connection-oriented network level protocols have been defined. The network layer is also responsible for inter-working between different data link layer protocols, where this is required.

• Exempel: IP, ICMP

Integration of IP in industrial applications

Schematic picture of network in manufacturing

Delivery material

Processing

Intermediate storage

Finished product

How to talk to PLC systems• IP address

Various protocols

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Applications that require communication

• Data collection of current information

for decision support

• Customer service requests

• Remote support

• Training

• Remote software updates

• Diagnostics

• Web services

• More precise planning

• Shorter lead times

• Reduced inventory capital

• Higher equipment utilization

• Reduced travel expenditures (VNC)

• Lower support and commissioning

costs

• Optimized delivery schedules

AdvantagesApplications

Transport layer

• The Transport Layer provides a message exchange between the two end points with known characteristics. A range of transport layers have been defined in the model, ranging from a minimal transport layer (TP0), through to a transport layer with full error and flow control (TP4).

• Examples: UDP, TCP.

TCP makes it possible to exchange data between different manufacturers of control systems

Name PLC range Protocols Hardware Solution

Software Solution

Altus AL400x Alnet II

Cegelec Alspa C80-35, C80-75 SRTP Cegelec

GE Fanuc GE 90-30, 90-70 SRTP GE

Mitsubishi AnA, AnU, QnA, QnAS Melsec A, Melsec Q

Omron Sysmac C, Sysmac CV, CS1 FINS TCP/IP

Rockwell ControlLogix, PLC5, SLC500 Ethernet/IP (Logix5000, PCCC)

SchneiderQuantum, others Modbus TCP/IP

TSX57, TSX7 Uni-TE TCP/IP

TSX7 Ethway (old generation)

SiemensSimatic S7 : 200, 300, 400Simatic S5 : 155U, 135U, 115U

Ind. Eth. S7, Ind. Ethernet S5

Sinec H1

TI CAMP

You Specific Through TCP/IP devt toolkit

Intranets• Definition: IEEE 802.3 in a production

environment

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2 IEEE 802.3CSMA/CD

1 Ethernet

3 Internet Protocol

6

5

4 UDPTCP

TCPUDP

TCPUDP

TCPUDP

TCPUDP

TCPUDP

TCPUDP

TCPUDP

RFC 1006UDP

ALNET II S5 R/W, S7, CAMP

Uni-TE v2 Modbus PCCC MELSEC A

MELSEC Q SRTP Fins Own

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Intranet in industry- discussion points

• Advantages: competitively priced, widely known, etablished, rapid devopment

• To discuss: realtime properties, environmental issues, security

It works if you select right equipment

• If the environment poses challenges

• If you need more know how

IP67

Fiber

More than one thing to think about

• Physical limitations• Safety and access security• Installation• Functional separations• Change and maintenance• Cost!• Ease of use

Intranet is cost effective

• Many suppliers – competitive prices• Really good performance compared with bespoke

industrial buses (GB/s)• Unmatched scalability(255 CPUs per network and

255 nodes per subnet)

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Ethernetnet physical limitations

• No of addresses, subnets, traffic control (switches)

• Length of cables, speed, no of drops, category, isolation

• Redundancy, fail over criteria

Security

• IP-to- IP communication (programmed in routers)• Automatic updates• Error reporting (SMTP trapping)• Traffic monitoring, jabber purging, data reduction• Certificates for VPN tunneling (IPSEC, Open

VPN)

Installation

• In which order?• Simulation? Sequence of data collection,

completeness criteria, data copy spawning• Operational changes ? (DB schema, root

nodes, path realignment)

Costs

• Scope of supply, specifications, supplier criteria

• Define standards : TCP/IP, IEC 61131-3 standard s/w and h/w (new:IEC 62399)

• Open Source/proprietary: Linux, Internet/ Windows, Android

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Speed

• Example:Printing press : control cycle speed: 4ms/scan, 108 setpoint changes per 8 msek on a 10MB/s intranet

Session layer

• The Session Layer is responsible for establishing and synchronising the dialogue between two end points, including whether the dialogue is full duplex, half duplex, etc. It can also provide synchronisation points, so that if the dialogue develops a fault, it can be resumed from the most recent “known good” point. Operating systems normally provide this function.

• Exempel: Windows Message Queue

Session layer

• The industrial protocol (“the software stack” ) uses the services of the operating system to perform the communication

• In most cases, the user protocol has to ensure the synchronization of the messages

• Microsoft operating system and Linux (incl. Android) dominates the market

Session layer is where you find software driversType Manufacturer Protocol PLCs range Smart card

Software stack

Serial Schneider Modbus RTU/Ascii, Master/slave Modbus devices Yes Yes

Serial Schneider UniTelway client/server TSX7, Premium Yes YesSerial Siemens AS511 Siemens S5 Yes YesSerial Siemens 3964/3964R Siemens Yes NoSerial Siemens TI-Dir TI 505 Yes YesSerial Siemens PPI+/PPI S7-200 Yes Yes

Serial Allen Bradley DF1 Half Duplex PLC5, SLC500 Yes No

Serial Omron Sysmac Way Yes No

Serial GE Fanuc SNP-X master GE 90-30/70 Yes Yes

FIP Schneider Fipway client/Server TSX7, Premium Yes No

ModBus + Schneider Modbus Plus Client/server Premium, Quantum Yes No

Reliance Allen Bradley Reliance Reliance SST card No

DH+, RIO Allen Bradley DH+ or Remote IO CLX, PLC5, SLC500 SST card No

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Platforms

• Servers: Microsoft (Win servers), IBM, Linux (many different)

• Cloud based services (AWS, Azure, GCS)• Embedded : Microsoft (Win CE), Linux • Java VM (many different)• Real time extensions VXWIN, CEWin

Presentation layer

• The Presentation Layer is responsible for any syntax conversion necessary between the local and remote system. The analogy of a translation service is often used to explain this.. Note that the presentation layer need not understand the meaning (or semantics) of the conversation, just the syntax (or grammar and structure of each language)

• Examples: ASCII, JPEG, XML, HTML5

Human machine interfaces

• Ergonomics – Interaction design• User acceptance• Security! Data entry controls• Data reuse• Work content: empowerment• SCADA plug-ins for network admin now

exists

Functional separation

• Which functions are controlled by which part of the system?

• Automatic, semiautomatic, manual• Data registration• Error handling• Operator dialog, data validation

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Maintenance and change

• On line changes possible?• Traffic control, load, security• System access• Backup, redundancy, identification

Application layer

• The Application Layer provides an interface to user applications, and provides basic operations such as file transfer, messaging transfer, etc. Note that this layer is not providing the actual application, rather application layer services; it could be viewed as making data exchanges with remote systems behave in the same way as an operating system call to resources on the local machine.

• Examples: Telnet, HTTP, DHCP, DNS, FTP, POP3, SSL, RTP, SNMP but also OPC, OPC UA.

Layer 7 is where the functional differences areProduct range Quick description Main Network(s) Main use

1a- Network Computer bus Interface

PC NIC (PCI, format) to connect SW to various PLCS through networks, using smart cards with embedded communication

Ethernet TCP/IP, Profibus, FIP, Modbus Plus, Serial

• Large architecture• SCADA, IHM• OPC Server, SuiteLink

server, DLL access1b- Network Software Drivers

Software drivers to connect SW application (Scada, IHM) to various PLCS through networks, using software drivers

Ethernet TCP/IP, serialProfibus

• Small architecture• SCADA, IHM• OPC Server, SuiteLink

server, DLL access2- Fieldbuses NIC for OEM market

PC NIC (PCI, PC/104, VME, CompactPCI format) to connect application (SoftPLC, Specific…) to I/O devices through fieldbuses

- Profibus DP, DeviceNet, EtherNet/IP, CanOpen, …

• SoftPLC, specific• Direct DP-RAM access

3- Network - PLC Scanners / Adapters

Connect a Rockwell PLC to a non-Rockwell network

Remote I/O, AS-i, Interbus-S, Profibus DP

•ControlLogix, SLC500, PLC5•CompactLogix, MicroLogix

4- Network gateway

Communications Gateway for bridging different industrial networks together

Eth >-> Eth, Eth <-> Serial, …

•PLCs connectivity

5- Embedded Network Interface

To embed a Network component into a Machine

Profibus DP • Embedded networking for OEM market.

6- Network diagnostics tools and connectors

Diagnose network problems, cutting troubleshooting time from hours to seconds

DeviceNet, Profibus • Network diagnostic

www.plant.com

Internet affects run time and remote diagnostics.

Connection via via www

Standardised protocol

TCP/IP (http and https

ports)

Internet services

E-mail,GPRS

Provider

Provider Provider

Provider

Router

Router

Router

Router

Local area network

Local area network

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www.plant.com, connect to existing machines

• A. Via telephone/modem/3G• B. Via Internet and ISP• C. Via Internet, LAN and firewall (VPN)

tunnel)

Industrial webserver

Www : hypertextbaserad information

Client / server architecture

WWW server

Computer w.

HTML filer

WWW klient

Internet web browser

Standards

protocol: HTTP, HTTPS

Language: HTML

Integrative advantages

• Simple integration between PLCs and administrative systems

• On line changes possible/allowed

Design principles

• Top down: Analyze a whole production unit (PNI diagram), build structure -implement

• Bottoms up: build ”islands of automation”, connect when you need

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Principal designs

• Physically and logically centralized, old example TDC3000 from Honeywell

• Physically and logically distributed, such as PLC networks from Siemens

• Mix of central and distributed functions, eg. ABB SCADAportal, Siemens TIA portal

• Physically distributed, logically centralised, webserver + web client. IIoT, f.ex. Siemens mindsphere.

Determine performance–not so easy! Common Global features I/OCard type 1 I/O card type 2• SoftPLC, Scada use Y (Fully for SCADA) Y• Customer type OEM, End-user, SI OEM• Co-processor on board Y Y• Direct DP-RAM access N Y• DP-Ram mapping Automatic Manual or automatic• Configuration flashable in Prom and autoboot mode

Y Y

• Unique API for all protocols Y N• Drivers for XP, 2000, NT4 Y Y• Windows DLL 32 bits Y Y• OPC server (Data Access v3.0, v2.05a & v1.0)

Y Y

• Wonderware compatible (with DAS or SuiteLink server)

Y N

• ActiveX control Y N• Live Conf. (add/del. Device, start/stop master, …)

N (use console) Y

• Configuration software under Windows Compulsory Optional + customizable• Remote configuration Remote N• Diagnostic software Y (local or remote) Y (local)• Driver source code Via toolkit or drivers

(1)Y (requires devt.)

• Card format PCI, PC/104, CompactPCI

Universal PCI, PC/104, VME, CompactPCI

• Pricing structure Global « all-in-one » Separate (HW/SW)• Bulk mode purchasing Y (per 25) Y (per 25)

Development, layer 1-3

• 2G, 3G, 4G (and soon 5G) and development is very rapid

• Frequencies: 868 Mhz, 2,4 GHz, 5 Ghz (and soon 5,61 GHz)

Wireless systems, many frequencies

Wireless OverviewWireless Overview

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Internet telephone technology

• CDMA (mostly used in the USA)– 800/1900 MHz.

• GSM – Quad band (1900/850) and

(1800/900 Mhz)– EDGE och GPRS

– Max 240 kBaud (100-130 kbaud typical)

– UMTS, HSPA– LTE (4G)

• Security– SSL, SSH v2.0 (Linux/Unix), FIPS 197

(USA), HTTPS …• Router/ Firewall

• NAT; port forwarding, VPN ,IP filteringing …

Utveckling, layer 7

• Synchonous variants of ethernet in order to counteract lack of determinism (Profinet,Powerlink..)

• New protocols and nodes with traffic control functions (programmable switches)

• ”All nodes are equal but some nodes are more equal than others”

Our new tower of Babel

• One webserver per unit/instrument• How to handle: XML• Integration through style sheets

Open platform - XML

DataRequests

URLWSDL

OutputXML

BinaryHTMLWMLCSVGIF

PALMSMSRDB

Agents

KPIsXML-based D

ataAbstraction

Data Connectors

PLC’sSCADA

HistoriansMES

CMMSDCSOPC

DatabaseXMLERP

Alerts

Quality

SAP Portal Services

AdvancedXML

authentication

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Internet based control

• < -http/https >

factoryt.ex. Gnosjö

Server

PC-styrning

Main officet.ex. Lund

Klient

DiagnosticsDiagnostics

MainteanceMainteance

Internet on the factory floor• Write once: debug everywhere• dhtml, .net, java, javascript, • xml gaining acceptance• virtualization of servers• java popular, open source dev´t (Eclipse)• Microsoft solution: .net and cloud • new platforms: android• geolocation new trend

Remote dagnostics via internetWhat you can do

Web browser access

Web camera

Graphic plug ins

View, read, write dataTrends

Diagnostics

Data navigation

Different data from different sources

Deliveries Process SCADA Packaging

Quality control

Administration

Web page

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Strategy

• Thin client: installed in browser; remote boot via Pixie boot (Intel)

• Thick client: needs local maintenance• Cloud based services, tuning support, on

line process support, middleware

One easy way to improve (Scania Oskarshamn)

• By informing the operators on-line about the production status with reference to the planned tact /plan, in following steps (forward stop) or in coming steps (back stop), the operators have a tool to dynamically adjust the production rate by reallocating breaks och perform maintenance and in this way time is saved which did not exist in the production plan : a good production becomes better

Lina 1

Lina 2

Lina 3

Production data base design

How to make a good production better

All time (24 h x 5 days)

Gross available time (paid time plus overtime)

Planned production time Shortages

Real production time Externalstoppages

Operating time

Planned stoppages

Unplannedstoppages

Net operating time (Ideal time)

Speed losses

Profitableoperating time

Defectproduction

System example

Writing of data directly from PLC code into databases

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System i praktiken

Processbild på intranet, XSYS Trelleborg

The internet of things• A whole new set !

THANK YOU!

Questions

www.indnetsoft.com