bilel modifications 1

7/29/2019 Bilel Modifications 1

1/68

5

2

20

13

Android SCADA platform / Graduation project

Dedication

I dedicate this work as a token of my

deep respect, my great love and

gratitude to:

My dear parents,

All members of my family,

And all my friends.

Acknowledgement

Abdallah Mahmoud _ ESPRIT


2/68

5

2

20

13


It is with great pleasure that I would first like to

express my gratitude to my dear supervisor in

both institutions ESPRIT and Millnia engineering:Mr Imed Ouardi, Ms Sana Ben Fadhel and Mr

Houssem Eddine Lassoued for the attention they

have given to my project throughout its various

stages from concept to completion and these

valuable tips.

I want also to thank all the team members

(ESPRIT MOBILE) among them M.Wael, M Imed

Amri and the same for M.Bechir Messabeb who

was a great help for me in Millinia engineering forsupport and encouragement.

I am indebted to all my teachers for their efforts

that have guided my steps throughout my

university studies; I take the same opportunity to

thank Mr. Karim MAGHREBI language for His help.

I finally want to express honor to the jury

members for agreeing to lend me their attention

and evaluate my work.



3/68

5

2

20

13


Table des matires

TABLE DES MATIRES.........................................................................................................3

LISTE DES TABLEAUX..........................................................................................................7

TABLE DES MATIRES.........................................................................................................8

GENERAL INTRODUCTION.................................................................................................9

GENERAL CONTEXT...........................................................................................................10

I-General Context..........................................................................................10

1-Project context............................................................................................................10

2-Introducing the Host company ...................................................................................10

3-Project issues..............................................................................................................10

4-Proposed Solution.......................................................................................................10

Conclusion......................................................................................................................10

1.GENERAL CONTEXT. ......................................................................................................11

I-General Context..........................................................................................11

1-Project context............................................................................................................11

2-Introducing the Host company ...................................................................................11

3-Project issues..............................................................................................................12

4-Proposed Solution.......................................................................................................13

Conclusion......................................................................................................................13

I-Mobile application......................................................................................15

II-Medium and Protocols................................................................................15

STATE OF ART .....................................................................................................................15

2.STATE OF ART ..................................................................................................................16

I-Mobile application......................................................................................16

1-Overview.....................................................................................................................16

2-Android Platform.........................................................................................................16

3-Highlights....................................................................................................................17

4-Weakness....................................................................................................................17

II-Medium and Protocols ...............................................................................18

1-Why Ethernet? Why TCP/IP?........................................................................................18



4/68

5

2

20

13


2-MODBUS Protocol ...................................................................................................... 20

a- EtherNet/IP.................................................................................................................21

b- PROFINET..................................................................................................................21

Managed by PROFIBUS and PROFINET International (PI), PROFINET is an application

protocol that uses familiar concepts from PROFIBUS that are implemented on the

physical layer of Ethernet. PROFINET is adopted by SIEMENS........................................21

c- EtherCAT...................................................................................................................22

EtherCAT (Ethernet for Control Automation Technology) is a high-performance,

industrial communication protocol for deterministic Ethernet. Published as part of IEC

61158, this open standard implements a master and slave architecture over standard

Ethernet cabling to transfer data with predictable timing and precise synchronization.

EtherCAT is adopted by BECKHOFF................................................................................22

3-MODBUS: Protocol of Choice.......................................................................22

a-Definition....................................................................................................................22

b-Services supported by Modbus...................................................................................22

c-Principle of Modbus exchanges...................................................................................23

d-MODBUS Addressing model........................................................................................24

4-RTU Modbus Protocol.................................................................................25

5-Modbus ASCII Protocol...............................................................................26

6-Modbus TCP/IP...........................................................................................26

a-Structure of a Modbus TCP/IP message.......................................................................27

III-SCADA SYSTEM..............................................................................................................29....................................................................................................................................... 29

1-What is SCADA?..........................................................................................................29

2-Components of SCADA System...................................................................................29

Field Instrumentation refers to the devices that are connected to the equipment or

machines being controlled and monitored by the SCADA system. These are sensors for

monitoring certain parameters; and actuators for controlling certain modules of the

system...........................................................................................................................30

These instruments convert physical parameters (i.e., fluid flow, velocity, fluid level,

etc.) to electrical signals (i.e. voltage or current) readable by the Remote Station

equipment. Outputs can either be in analog (continuous range) or in digital (discrete

values). Some of the industry standard analog outputs of these sensors are 0 to 5 volts,

0 to 10 volts, 4 to 20 mA and 0 to 20 mA. The voltage outputs are used when the

sensors are installed near the controllers (RTU or PLC). The current outputs are usedwhen the sensors are located far from the controllers...................................................30

Likewise, digital and analog inputs are used for control. For example, digital inputs can

be used to turn on and off modules on equipment. While analog inputs are used to

control the speed of a motor or the position of a motorized valve.................................30

Field instrumentation connected to the plant or equipment being monitored and

controlled are interfaced to the Remote Station to allow process manipulation at a

remote site. It is also used to gather data from the equipment and transfer them to the

central SCADA system. The Remote Station may either be an RTU (Remote Terminal

Unit) or a PLC (Programmable Logic Controller). It may also be a single board or

modular unit...................................................................................................................30

The Communication Network refers to the communication equipment needed totransfer data to and from different sites. The medium used can either be cable,



5/68

5

2

20

13


telephone or radio. The use of cable is usually implemented in a factory. This is not

practical for systems covering large geographical areas because of the high cost of the

cables, conduits and the extensive labor in installing them. The use of radio offers an

economical solution. Radio modems are used to connect the remote sites to the host.

An on-line operation can also be implemented on the radio system. For locations

wherein a direct radio link cannot be established, a radio repeater is used to link these

sites...............................................................................................................................31

The Central Monitoring Station (CMS) is the master unit of the SCADA system. It is in

charge of collecting information gathered by the remote stations and of generating

necessary action for any event detected. The CMS can have a single computer

configuration or it can be networked to workstations to allow sharing of information

from the SCADA system.................................................................................................31

..................................................................................................................................... 32

There are many major companies who offer different SCADA system solutions

mentioning some of them for example: Wonderware, Intellution, Rockwell Software,

Siemens, and ABBGenerally the solutions made by these companies are complex,

Ramified, made for a huge project and most of all very much costly.............................32

For the Android SCADA solutions there are none, at least as available solutions, and if

there are its only for monitoring and supervision, that means just an Android

application which is connected with the CMS (Central Monitoring Station) and offers to

the user a real-time visualization, a GUI (graphical user interface). As an example for

such type of solutions we can mention TeslaScada who developed applications that can

offer communication between an android device and industrial automation applications

and visualization............................................................................................................32

As was mentioned before a SCADA system contains four components: field

instrumentation, communication network, remote station and the central monitoring

station. The two first parts are hardware equipment and cant be replaced but the two

last are basically a software solution and there our project starts.................................33

So the idea was to create a solution which is an Android application able tocommunicate with the field instrumentation, collect data, saved to a data-base and

present it on the screen.................................................................................................33

Conclusion......................................................................................................................33

Modbus is a messaging protocol uses application layer that provides client / server

communication between devices connected to different networks, this is what we were

talking the most in this chapter, plus the concept of SCADA in general.........................33

Specification and functional analysis..............................................................................34

3.SPECIFICATION AND FUNCTIONAL ANALYSIS......................................................35

1-Agile Methodologies....................................................................................................402-Mobile-D: A methodology for the development of mobile applications........................41

A-Mobile-D introduction................................................................................41

B-Why Mobile-D for mobile application?.........................................................42

C-Mobile-D in phases.....................................................................................43

D-Mobile-D methodology evaluation..............................................................45

Advantages....................................................................................................................45

Disadvantages...............................................................................................................47

Design Phase..................................................................................................................48



6/68

5

2

20

13


4.DESIGN PHASE ..................................................................................................................49Implementation..............................................................................................................54

5.IMPLEMENTATION .........................................................................................................55

LIST OF ABBREVIATIONS.................................................................................................60

BIBLIOGRAPHIE ..................................................................................................................61

ANNEX.....................................................................................................................................61Read Coils 01 (0x01) .....................................................................................................63

Read Discrete Inputs 02 (0x02)......................................................................................63

Read Holding Registers 03 (0x03)..................................................................................64

Read Input Registers 04 (0x04)......................................................................................65

Write Single Coil 05 (0x05).............................................................................................66Write Single Register 06 (0x06).....................................................................................66

Write Multiple registers 16 (0x10)..................................................................................67



7/68

5

2

20

13


Liste des tableaux

TABLE 1: GENERAL FEATURES OF SOME OF AGILE SOFTWAREDEVELOPMENT METHODS.......................................................................................1

TABLE 2: MOBILE-D AND MOBILE SOFTWARE DEVELOPMENTCHARACTERISTICS......................................................................................................4

TABLE 3: DESCRIPTION OF THE USE CASE CONSULT THECOLLECTED DATA.........................................................................................................4

TABLE 4: DESCRIPTION OF THE USE CASE RETRIEVE THEDEVICE STATE..................................................................................................................4



8/68

5

2

20

13


Table des matiresFIGURE 1: .................................................................................................................................4

FIGURE2: MOBILE-D...............................................................................................................4

FIGURE3: MOBILE-D PHASES...............................................................................................4

FIGURE4: ANNUAL GROWTH OF INDUSTRIAL ETHERNET

INFRASTRUCTURE.................................................................................................................4

FIGURE5: CONSTRUCTION OF A TCP/IP-ETHERNET DATA PACKET..........................4

FIGURE6: INDUSTRIAL ETHERNET PROTOCOLS MARKET SHARE............................4

FIGURE7: PUBLIC FUNCTION CODE DEFINITION...........................................................4

FIGURE8: COMMUNICATION ENTER MASTER AND SLAVE.........................................4

FIGURE9: MODBUS ADDRESSING MODEL.......................................................................4

FIGURE10: RTU MODBUS FRAME STRUCTURE...............................................................4

FIGURE11: ASCII MODBUS FRAME STRUCTURE............................................................4

FIGURE12: MANAGING A MODBUS TCP/IP CONNECTION............................................4

FIGURE13: CONSTRUCTION OF A MODBUS TCP DATA PACKET................................4

FIGURE14: READ COILS STATE DIAGRAM.......................................................................4

FIGURE15: GLOBAL USE CASE DIAGRAM........................................................................4

FIGURE16: SEQUENCE DIAGRAM WITHOUT HUMAN INTERACTION....................4

FIGURE17: OBJECTS SEQUENCE DIAGRAM.....................................................................4

FIGURE18: ACTIVITY DIAGRAM.........................................................................................4

FIGURE19: CLASS DIAGRAM................................................................................................4

FIGURE20: THE SHAPE OF THE USED DEVICE.................................................................4

FIGURE21: MODBUS SLAVE INTERFACE..........................................................................4

FIGURE22: WIRESHARK INTERFACE.................................................................................4



9/68

5

2

20

13


General Introduction

Android has become increasingly interesting for hardware development.Now, we should soon be able to connect joysticks, custom hardware, sensors and

other devices and make a platform Android almost in every field and among

those fields we can find the industrial field.

New API Management hardware enables everyone to develop hardware

accessories for Android, from individual amateurs to major global brands. You

do not have to sign an NDA, and you do not need a special license material, the

aspects concerning Apple's policy does not exist in Android.

We have always been able to connect an Android device to a computer,

but until a while ago, there was no way for Android applications to interact with

other hardware via Ethernet or any other port. In this context, we explore new

support for input output devices, as well as new opportunities for applications to

communicate with devices via Ethernet and by using TCP / IP protocol.

Among the many fields that can interact with Android there is the

industrial field. Indeed, this interaction is more or less new, as seeking we

couldnt find enough tests and experiments that concern this meeting. We had

the courage to involve in this project and dive into this experience.

It is in this context that our project is: it is study, design, develop an

embedded intelligent system based on Android.

Throughout this report, we will discuss the different stages of our project,

starting with a presentation of the basic concepts in the understanding of our

subject, then we present the various existing solutions and finally in the last

section, we shall a detailed description of the formulated solution.



10/68

5

2

20

13



Chapter I General context

Introduction

I- General Context

1- Project context

2- Introducing the Host company

3- Project issues

4- Proposed SolutionConclusion


11/68

5

2

20

13


1.General context.

Introduction

We present in this chapter a preliminary study of the project. At first, we

present the environment of the internship. Subsequently, we describe the

problem and the main objectives of the project.

I- General Context

1- Project context

As part of the education of Telecommunications engineers in (ESPRIT),

we had the opportunity to do our end of studies project for the National Diploma

in Telecommunications Engineering at Millinia engineering and with ESPRIT

Mobile team at ESPRIT, usually the project is intended to complement our

academic training acquired during the last three years, and bring us into

professional life through implementation of our knowledge, use of acquired

skills and to test our mind engineer. The project is to design and implement an

application based Android on system in order to switch to the open-source

programming and to reduce costs.

2- Introducing the Host company

Millenia Engineering is a limited company (Ltd) working in partnership

with renowned manufacturers. Its initial objective is to offer a national andinternational clients outsourcing tasks and design studies in the fields of

electronics and telecommunications to make some projects feasible design of

new products. These tasks require, particularly in Europe, a major investment

behind which stands as a major obstacle to the achievement.

Millenia Engineering has several projects in various fields of activities. It has

worked in the design and development of IT solutions for the industry.

Furthermore, Millenia Engineering has several other activities in Tunisia and



12/68

5

2

20

13


around the world in partnership with major companies for the implementation of

systems with high technological added value in the field of BMS (building

management system).

Millenia participated in collaboration with Tunisian research centers (Sup'Com,

ENIT ...) in several pilot projects.

These observations made, the activity of Millenia Engineering covers four main

areas:

- Electronic communications: communication, signal processing, wireless

connections ...

- Instrumentation.

- Computer peripheral.

- General public (Consumer Electronics).

3- Project issues

To achieve an embedded intelligent system based on Android and that

meets the needs requested by Millinia-Engineering and different potential clients

(companies, people), it is important to focus primarily on the issues of the

project in order to be organized.

Thus, we will determine the scope of action and the feasibility of this

project. The project involves multiple environments; it starts on the developer's

machine, through a phase of communication with some devices, to the actual

testing environment to finally arrive at the surround production. In addition, the

project can be transferred from one environment to another several times before

it is finalized.

In this project, the provision of an environment with another does not

happen the same way that you work with a single environment, and do not

present the same degree of complexity, as in a development environment, a

simple compilation is enough, and even errors can be detected, but the

deployment of the solution on the other environments especially communication



13/68

5

2

20

13


with industrial equipment has several constraints and challenges more if we want

to transfer only a very specific functionality, without affecting other features,

that makes this difficult and painful hence the need to develop an approach to

achieve this task manipulation.

There are also other scenarios the system can force us to design a flexible

solution such as:

System that meets the specific needs in terms of functionality.

System that meets specific needs in terms of personalization.

System which has a margin large enough scalability

Demonstrate the ability to merge the intelligence of Android with industrial

environment.

4- Proposed Solution

The solution proposed as an embedded intelligent system based on

Android OS solution is a SCADA platform based on Android, it operates on two

levels, the first will have the role of ensuring the communication and the

interaction with the external environment represented in different external

devices, the second level allows the user to interact with the application by

providing a GUI which offers several advanced features.

Conclusion

This chapter has served us to put our project in its frame. Indeed, our

graduation project is made in Millinia-Engineering, which is to create an

application based on Android which communicates with an industrial

environment, in order to monitor and increase technological innovation in the

both fields.

In the next chapter we introduce the necessary concepts that lead to understand

this project: an overview of the chosen solution as a concept and as a platform



14/68

5

2

20

13


for software development and other existing solutions and a comparison of these

solutions to focus on their strengths and weaknesses.



15/68

5

2

20

13



Chapter II State of Art

Introduction

I- Mobile application

II- Medium and Protocols


16/68

5

2

20

13


2.State of Art

IntroductionIn this chapter we will present some concepts and

technologies that will be used to better understand our subject,

this chapter is divided into three parts which are as follows.

The first part will be devoted to the presentation of the concept

and principle of the mobile application and the, the second part

we will talk deeply the MODBUS protocol, causes of choice, theareas of activity, operation mode and the different modes of

use, and in the end we will be talking about the SCADA concept

and the new challenges with a comparative study of similar

products on the market.

I- Mobile application

1- Overview

A mobile application is a downloadable program on a free of charge, or

paid, or executable, from the operation system of the phone or other device, and

is specific for mobile operating system and developed by unique and specific

language required with the publishers offered by the company that provides the

system and offers some tools to application development.

2- Android Platform

Android is an open source Linux-based operating system designed

primarily for touch screen mobile devices such as smart phones and tablet

computers. Initially developed by Android, Inc., which Google backed

financially and later bought in 2005, This open-source code and permissive



17/68

5

2

20

13


licensing allows the software to be freely modified and distributed by device

manufacturers, wireless carriers and enthusiast developers

The open-source code as a foundation for community-driven projects,

which add new features for advanced users or bring Android to devices which

were officially released running other operating systems.

3- Highlights Security: Android OS is proven to have superior security when

compared to other mobile phone operating systems. One of the factors that

contribute to the improved security that Android OS has is the fact that all appsrequire authorization in order to access the various phone resources such as

memory, installation and network.

Rich multimedia capabilities: Android OSs multimedia

capabilities range from media transfer to multimedia streaming. Android users

also get to enjoy other benefits such as Multilanguage support, tethering,

massive external storage capability and multitasking among others.

Easy to operate: Many users appreciate devices that are easy to

operate. Android OS is highly preferred due to its simplicity in operation.

Besides being easy to operate, this operating system is less prone to crashing,

which makes it very convenient to both first-time and experienced users to

access applications without any worries.

4- Weakness

Fragmentation: Android OS has several versions, devices running

Android comes in many shapes and sizes, available in different screen sizes and

rated in vast numbers of different performance levels. All these factors

contributed to the growing fragmentation of Android OS which burden

developers to optimize apps according to each category. It was extremely

challenging and time consuming.



18/68

5

2

20

13


Battery Drainage and overheating: Overheating of Android

device has been a big issue and it has a very short battery life.

Internet connection: Most Android devices require a simultaneous

Internet connection

II- Medium and Protocols

1- Why Ethernet? Why TCP/IP?

No doubt, Ethernet and the TCP/IP Protocol are achieving more and

more acceptance in the industrial automation technology. Major technicaladvances such as Fast Ethernet, Switching and Full Duplex communication have

turned the good old Ethernet into a powerful communication system with a

magical attraction to industrial users and manufacturers.

a_ Ethernet

A 2004 report measured the industrial Ethernet infrastructure market at

$124 million. This latest study finds the market grew to more than $260 million

in 2006, and will continue to increase 29% annually, reaching $995 million in

2011.

Figure4: Annual growth of industrial Ethernet infrastructure



19/68

5

2

20

13


Although Ethernet has secured a growing share of the global automation

networking market, researches confirm that numerous other types of industrial

networks have also been expanding over the last several years. Ultimately, some

of the applications now served by the many industrial device networks and

motion control networks will migrate to industrial Ethernet.

Ethernet has several advantages:

Greater bandwidth and larger data packages for communications

with more and more intelligent industrial devices.

Connecting and addressing more devices over wider areas.

Quicker Real-Time communication with synchronization good

enough even for demanding motion control applications.

Integration to the office world, IT-functions, Internet/Intranet,

remote configuration. This is basically TCP/IP on Ethernet with application

protocols such as SNMP, FTP, MIME, HTTP. Communications over routers and

servers where IP-addressing and TCP transport are mandatory.

b_ TCP/IP Protocols

TCP/IP refers to the Transmission Control Protocol and Internet Protocol

which were first introduced in 1974. TCP/IP is the foundation for the World

Wide Web and forms the transport and network layer protocol of the internet that

commonly links all Ethernet installations world-wide. Simply stated,

TCP/IP allows blocks of binary data to be exchanged between computers.

The primary function of TCP is to ensure that all packets of data are

received correctly, while IP makes sure that messages are correctly addressed

and routed. TCP/IP does not define what the data means or how the data is to be

interpreted; it is merely a transport protocol.



20/68

5

2

20

13


Figure5: CONSTRUCTION OF A TCP/IP-ETHERNET DATA

PACKET

Ethernet communication with TCP/IP is non-deterministic and the

reaction time is often above 100ms. Remote I/O demands reaction in the 5-10ms

regions. Motion Control craves even higher demands determinism with cycle

times into the microsecond region. The conflict between IT-traffic using TCP/IP

and the achievement of real-time performance is dealt with in several different

ways.

By using standard TCP/IP embedding a field bus protocol at the

application level maintains full IT-openness. You just tunnel the field bus

protocol on Ethernet. Reaction time is around 100ms like standard Ethernet. In

local segments with few devices and small data packages the reaction time goes

down to 20ms. By using UDP instead of TCP the reaction time comes down to

10ms at best. Direct MAC-addressing in a local segment can bring reduce this

closer to 1ms. Time synchronization can be added such as that obtained by

applying IEC61588. Bandwidth for TCP/IP traffic remains at 90-100%.

2- MODBUS Protocol

Major industrial Ethernet protocols



21/68

5

2

20

13


Industrial Ethernet protocols offer many varieties for high speeds, target

applications, determinism, and compatibility with standard Ethernet. Each

technology has its benefits and limitations, and the best choice often depends

on the specific requirements of the system. To provide high-performance

measurements and real-time control, National Instruments products can easily

plug into the most popular industrial Ethernet protocols.

In his report "The world market for industrial Ethernet", the market

research firm IMS Research has established a classification protocol Ethernet

equipment sales, and the result appears in the figure below.

Figure6: Industrial Ethernet protocols Market share

a- EtherNet/IP

Developed by Rockwell Automation and managed by the Open

DeviceNet Vendors Association (ODVA), EtherNet/IP extends the common

industrial protocol (CIP) of DeviceNet to Ethernet. EtherNet/IP is an applicationlayer protocol that uses TCP for general messages and user datagram protocol

(UDP) for I/O messaging and control. UDP is a multicast protocol that routes

packets from the controller to multiple destinations.

b- PROFINET

Managed by PROFIBUS and PROFINET International (PI), PROFINET

is an application protocol that uses familiar concepts from PROFIBUS that are



22/68

5

2

20

13


implemented on the physical layer of Ethernet. PROFINET is adopted by

SIEMENS.

c- EtherCAT

EtherCAT (Ethernet for Control Automation Technology) is a high-

performance, industrial communication protocol for deterministic Ethernet.

Published as part of IEC 61158, this open standard implements a master and

slave architecture over standard Ethernet cabling to transfer data with predictable

timing and precise synchronization. EtherCAT is adopted by BECKHOFF.

3-MODBUS: Protocol of Choice

a- Definition

The Modbus protocol was developed in 1979 by Modicon, Incorporated,

for industrial automation systems and Modicon programmable controllers. It has

since become an industry standard method for the transfer of discrete/ analog I/O

information and register data between industrial control and monitoring devices.

Modbus is now a widely-accepted, open, public-domain protocol that requires a

license, but does not require royalty payment to its owner.

MODBUS is an application layer messaging protocol, positioned at level

7 of the OSI model that provides client/server communication between devices

connected on different types of buses or networks. The Internet community can

access MODBUS at a reserved system port 502 on the TCP/IP stack.

b- Services supported by Modbus

The Modbus protocol provides 19 different functions. They are

characterized by a function code (in hexadecimal). The different function codes

are detailed in the table below.



23/68

5

2

20

13


Figure7: Public Function Code Definition

c- Principle of Modbus exchanges

Modbus devices communicate using a master-slave (client-server)

technique in which only one device (the master/client) can initiate transactions

(called queries). The other devices (slaves/servers) respond by supplying the

requested data to the master, or by taking the action requested in the query. A

slave is any peripheral device (I/O transducer, valve, network drive, or other

measuring device) which processes information and sends its output to the

master using Modbus. The Acromag I/O Modules form slave/server devices,

while a typical master device is a host computer running appropriate application

software. Other devices may function as both clients (masters) and servers

(slaves).



24/68

5

2

20

13


Figure8: Communication enter Master and Slave

Masters can address individual slaves, or can initiate a broadcast message

to all slaves. Slaves return a response to all queries addressed to them

individually, but do not respond to broadcast queries. Slaves do not initiate

messages on their own, they only respond to queries from the master.

d- MODBUS Addressing model

The address of each subscriber is independent of its physical location. It

ranges from 1 to 64 and must not be assigned sequentially. Subscribers are

required to have different addresses.

In a MODBUS PDU each data is addressed from 0 to 65535. It also

defines clearly a MODBUS data model composed of 4 blocks that comprises

several elements numbered from 1 to n.



25/68

5

2

20

13


Figure9: Modbus addressing model

4- RTU Modbus Protocol

When using the RTU Modbus protocol, the communication message

structure is as follows:

Figure10: RTU Modbus frame structure

-The address field contains the address of the slave instrument to which

the message is being sent. In theory, one can connect up to a maximum of 245

apparatuses (slaves).

-The Function field contains the function ID that has to be carried out by

the slave.

- The Data field contains the data sent to the slave or the data sent by the

slave as a response to a question.



26/68

5

2

20

13


-The CRC field permits both the master and slave to check whether there

are transmission errors.

5-Modbus ASCII Protocol

The Modbus ASCII protocol is normally used in applications that need to

communicate via modem.

The functions and addresses available are the same as the RTU version,

but the characters transmitted are in ASCII and the termination of the message is

not done via the time but with return characters.

The structure of the communication message structure is as follows:

Figure11: ASCII Modbus frame structure

-The address field contains the address of the slave instrument to which

the message is being sent.

- The Function field contains the function ID that has to be carried out by

the slave.

- The Data field contains the data sent to the slave or the data sent by the

slave as an answer to a question. The maximum length allowed is 32 consecutive

registers.

- The LRC field permits both the master and slave to check whether there

are transmission errors.

6-Modbus TCP/IP

Modbus TCP/IP (also Modbus-TCP) is simply the Modbus RTU protocol

with a TCP interface that runs on Ethernet. The Modbus messaging structure is

the application protocolthat defines the rules for organizing and interpreting thedata independent of the data transmission medium.



27/68

5

2

20

13


TCP/IP refers to the Transmission Control Protocol and Internet

Protocol, which provides the transmission medium for Modbus TCP/IP

messaging. Simply stated, TCP/IP allows blocks of binary data to be exchanged

between computers. The primary function of TCP is to ensure that all packets of

data are received correctly, while IP makes sure that messages are correctly

addressed and routed. Note that the TCP/IP combination is merely a transport

protocol, and does not define what the data means or how the data is to be

interpreted (this is the job of the application protocol, Modbus in this case).

Figure12: Managing a Modbus TCP/IP connection

a- Structure of a Modbus TCP/IP message

Modbus TCP/IP uses TCP/IP and Ethernet to carry the data of the

Modbus message structure between compatible devices. That is, Modbus TCP/IP

combines a physical network (Ethernet), with a networking standard (TCP/IP),

and a standard method of representing data (Modbus as the application protocol).

In practice, Modbus TCP embeds a standard Modbus data frame into a

TCP frame, without the Modbus checksum, as shown in the following diagram.



28/68

5

2

20

13


Figure13: CONSTRUCTION OF A MODBUS TCP DATA PACKET



29/68

5

2

20

13


III- SCADA system

1- What is SCADA?

SCADA (Supervisory Control And Data Acquisition) system refers to

the combination of telemetry and data acquisition. It consists of collecting

information, transferring it back to a central site, carrying out necessary analysis

and control, and then displaying this data on a number of operator screens. The

SCADA system is used to monitor and control a plant or equipment. Control

may be automatic or can be initiated by operator commands. SCADA systems

were first used in the 1960s.

SCADA stands for supervisory control and data acquisition. It generally

refers to an industrial control system: a computer system monitoring andcontrolling a process. The process can be industrial, infrastructure or facility-

based as described below:

Industrial processes include those of manufacturing, production,

power generation, fabrication, and refining, and may run in continuous, batch,

repetitive, or discrete modes.

Infrastructure processes may be public or private, and include watertreatment and distribution, wastewater collection and treatment, oil and gas

pipelines, electrical power transmission and distribution, Wind Farms, civil

defense siren systems, and large communication systems.

Facility processes occur both in public facilities and private ones,

including buildings, airports, ships, and space stations. They monitor and control

HVAC, access, and energy consumption.2- Components of SCADA System



30/68

5

2

20

13


i- Field Instrumentation

Field Instrumentation refers to the devices that are connected to the

equipment or machines being controlled and monitored by the SCADA system.

These are sensors for monitoring certain parameters; and actuators for

controlling certain modules of the system.

These instruments convert physical parameters (i.e., fluid flow, velocity,

fluid level, etc.) to electrical signals (i.e. voltage or current) readable by the

Remote Station equipment. Outputs can either be in analog (continuous range) orin digital (discrete values). Some of the industry standard analog outputs of these

sensors are 0 to 5 volts, 0 to 10 volts, 4 to 20 mA and 0 to 20 mA. The voltage

outputs are used when the sensors are installed near the controllers (RTU or

PLC). The current outputs are used when the sensors are located far from the

controllers.

Likewise, digital and analog inputs are used for control. For example,

digital inputs can be used to turn on and off modules on equipment. While

analog inputs are used to control the speed of a motor or the position of a

motorized valve.

ii- Remote Station

Field instrumentation connected to the plant or equipment being

monitored and controlled are interfaced to the Remote Station to allow process

manipulation at a remote site. It is also used to gather data from the equipment

and transfer them to the central SCADA system. The Remote Station may either

be an RTU (Remote Terminal Unit) or a PLC (Programmable Logic Controller).

It may also be a single board or modular unit.



31/68

5

2

20

13


iii- Communication Network

The Communication Network refers to the communication equipment

needed to transfer data to and from different sites. The medium used can either

be cable, telephone or radio. The use of cable is usually implemented in a

factory. This is not practical for systems covering large geographical areas

because of the high cost of the cables, conduits and the extensive labor in

installing them. The use of radio offers an economical solution. Radio modems

are used to connect the remote sites to the host. An on-line operation can also be

implemented on the radio system. For locations wherein a direct radio link

cannot be established, a radio repeater is used to link these sites.

iv- Central Monitoring Station (CMS)

The Central Monitoring Station (CMS) is the master unit of the SCADA

system. It is in charge of collecting information gathered by the remote stations

and of generating necessary action for any event detected. The CMS can have a

single computer configuration or it can be networked to workstations to allow

sharing of information from the SCADA system.

A Man-Machine Interface (MMI) or Human Machine Interface (HMI)

program will be running on the CMS computer. A mimic diagram of the whole

plant or process can be displayed onscreen for easier identification with the real

system. Each I/O point of the remote units can be displayed with corresponding

graphical representation and the present I/O reading. The flow reading can be

displayed on a graphical representation of a flow meter. A reservoir can be

displayed with the corresponding fluid contents depending on the actual tanklevel. Set-up parameters such as trip values, limits, etc. are entered on this



32/68

5

2

20

13


program and downloaded to the corresponding remote units for updating of their

operating parameters.

The MMI program can also create a separate window for alarms. The

alarm window can display the alarm tag name, description, value, trip point

value, time, date and other pertinent information. All alarms will be saved on a

separate file for later review. A trending of required points can be programmed

on the system. Trending graphs can be viewed or printed at a later time.

Generation of management reports can also be scheduled on for a specific time

of day, on a periodic basis, upon operator request, or event initiated alarms.

v- Overview of Existing Solutions

There are many major companies who offer different SCADA system

solutions mentioning some of them for example: Wonderware, Intellution,

Rockwell Software, Siemens, and ABBGenerally the solutions made by these

companies are complex, Ramified, made for a huge project and most of all very

much costly.

For the Android SCADA solutions there are none, at least as available

solutions, and if there are its only for monitoring and supervision, that means

just an Android application which is connected with the CMS (Central

Monitoring Station) and offers to the user a real-time visualization, a GUI

(graphical user interface). As an example for such type of solutions we can

mention TeslaScada who developed applications that can offer communication



33/68

5

2

20

13


between an android device and industrial automation applications and

visualization.

vi- Choice of solution

As was mentioned before a SCADA system contains four components:

field instrumentation, communication network, remote station and the central

monitoring station. The two first parts are hardware equipment and cant be

replaced but the two last are basically a software solution and there our project

starts.

So the idea was to create a solution which is an Android application able

to communicate with the field instrumentation, collect data, saved to a data-base

and present it on the screen.

Conclusion

Modbus is a messaging protocol uses application layer that provides

client / server communication between devices connected to different networks,

this is what we were talking the most in this chapter, plus the concept of SCADA

in general.



34/68

5

2

20

13



Chapter IIISpecification and functional

analysis

Introduction

I- Functional Specification

II- Use case diagrams

III- Sequence diagram

IV- Methodology of development


35/68

5

2

20

13


3.Specification and functional analysis

Introduction

This chapter specifies characteristics of our project, consisting of the

mobile application.

The first section will be an overall description of the application. In the

second part we will detail the system-required features. The third part aims to

specify some nonfunctional requirements. Then we will present some use case

and sequence diagrams.

I- Functional Specification

1- Overall application description

This application answers to a number of required specificities,encompassing real-time data delivery and communication between industrial

devices and the Android device. Usage is generally encouraged through the mass

collaboration phenomenon; the more data there is, the more often the system

should collected and save it to send later.

2- Functional system requirements

Our application has to fulfill a number of requisites in order to satisfy the

users needs.

Communicate with the industrial device: the first and one the main

requirements in our project is to make our Android device able to communicate

with the industrial device by using the adequate frame with the Modbus protocol,



36/68

5

2

20

13


and that can be achieved when the other device respond and send back an

acknowledgment message.

Collect the data: The Android device must receive back the

demanded information within a Modbus frame and extract the suitable

information.

Saving collected data: The application has the role to save the

received information into a local database and add every time some details that

may be useful later.

Send information via internet: The application has the role to send

the suitable information to a predefined Google-Cloud account via internet

network by using the 3G technology.

Display information: A local user would be able to visualize the

collected data on the device screen by choosing to show a table or a graphical

line chart.

Retrieve the devices state: The local user would be capable to

visualize the Android device connectivity which is the 3G internet connectionand the Ethernet connection between the Android device and the industrial

device.

3- Nonfunctional requirements

In addition to the functional requirements developed above, we must take

into account the following constraints:

The application must be effective and must ensure continuity of

operation.

It must meet the physical capabilities of devices equipped with the

Android OS.

It should be compatible with the versions above the API 3.0 It must be compatible with the different screen resolutions.



37/68

5

2

20

13


The response time of the whole system must be acceptable for use in

real time; the system must be secure and stable.

The design of the application must be attractive, understandable,

clear, easy to handle and respect the usual ergonomics distributed applications.

II- Use case diagrams

1- Global use case diagram

The user, having already login in to the application can check the

devices stat of network connection or to the industrial component, he can also

consult the collected data by visualizing a line chart or just consult database

table; on the other side the user can check the critical collected data by

consulting any device has an internet access.

Figure15: Global Use Case Diagram

2- Textual description of the use case diagram

This section will be devoted to the presentation of the main use cases.

i. Use case Consult the collected data



38/68

5

2

20

13


This diagram shows the different aspects of what we call consult

collected data, which we present in this table:

Use case name Consult the collected dataActors UserShort

description

The user will access the application and

retrieve the collected informationPre-conditions Authentication acceptedPost-conditions N/AMain flow -The user accesses the application

-The user can choose between consult the

whole saved data from a table or just visualize the

last information in a chart

-The system displays the desired choiceAlternate flow An error in the databaseException flow N/ATable 3: Description of the use case Consult the collected data

ii. Use case- Retrieve the device state

This diagram shows the different aspects of what we call retrieve the

device state, which we present in this table:

Use case name Retrieve the device state

Actors UserShort

description

The user will access the application and

check the state of his devicePre-conditions Authentication acceptedPost-conditions N/AMain flow -The user accesses the application

-The user will be able to visualize in the

main screen the state of internet connectivity and the

state of Ethernet connection.Alternate flow N/A



39/68

5

2

20

13


Exception flow N/ATable 4: Description of the use case Retrieve the device state

III- Sequence diagram

1- System sequence diagram

Figure16: Sequence diagram without human interaction

2- Description

This diagram shows the interaction sequentially between the system and

other actors.

So as a start the application will start communication to the industrial

device by sending a request frame asking for the device state or some registers

values, this device will respond by sending back the demanded data in

hexadecimal format, so the application will convert it into decimal then extract

the wanted value and saved into the local database (SQLITE D.B).

In case of attempting a critical value predefined by developer the

system will convert the last database file to an excel or text file and then will ask



40/68

5

2

20

13


the Google-Drive platform for the authentication, once it is agreed the system

will send him this file, an acknowledgment will be received.

This diagram shows also the interaction sequentially between the actor

and the system. So the user will start using the application he will have to enter

the correct predefined password, once access agreed the user will find himself in

the main screen where he will have the ability to check the state of systems

connectivity (internet and Ethernet), also he will be able to visualize the last

collected data in a line chart graph or just read the values from a table. Both

operations require communication between the system and his Data-Base.

IV- Methodology of development

1- Agile Methodologies

The "agile methods" are designed to reduce the software lifecycles by

first developing a minimum version, then integrating the functions through an

iterative process based on consumers feedback and tests performed throughout

the development cycle.

The origin of agile methods is related to the instability of the

technological environment and the fact that customers are often unable to define

their needs comprehensively from the beginning of the project. The term "agile"

is referring to the ability to adapt to context switches and changes in

specifications during the intervening development process. In 2001, 17 people

started and developed the Agile Manifesto whose translation is as follows:

Individuals and interactions rather than processes and tools.

Software development rather than exhaustive documentation.

Collaboration with the client rather than contract negotiation.

Openness to change rather than following a rigid plan.

With agile methods, the client is the full driver of his project and reaps

the result of his software relatively quickly.



41/68

5

2

20

13


Table 1: General features of some of agile software development

methods

2- Mobile-D: A methodology for the development of mobile applications

A-Mobile-D introduction

While many agile methods have been presented, none of them is

specifically tailored for the development of mobile software.

Mobile-D is an agile approach for mobile equipment, based on Extreme

Programming XP (practice), Crystal methodology (scalability) and Rational

Unified Process (lifecycle insurance). It is designed for the specific development

of the mobile application and the quality standards of the industry. The ideal case

is to have less than ten developers working in an office.

The directors aim to provide a fully functional incremental mobile

application in several iterations. The development work is divided into phases,

i.e. exploration, initialize, productionize, stabilize, and test and set system.



42/68

5

2

20

13


In practice, each phase consists of nine major elements: phase and stage,

online architecture, mobile test-driven development, continuous integration, pair

programming, metrics, process improvement software agile, customer off-site,

and concentration of the User-Centered.

B-Why Mobile-D for mobile application?

Figure 1

By combining the benefits of the three agile methods, XP in terms of

practices, Crystal family of methodologies in terms of scalability and Rational

Unified Process in the terms of life-cycle coverage

, Mobile-D meets the requirements for the development of mobile

application. The table below shows that Mobile-D is suitable for mobile

application development.



43/68

5

2

20

13


Table 2: Mobile-D and mobile software development characteristics

C-Mobile-D in phases

Figure2: Mobile-D



44/68

5

2

20

13


The Mobile-D process goes through 5 principle phases:

Explore

The purpose of the Explore phase is the planning and establishment of

the incipient project. A well planned deed is half done is a saying to be also

remembered in the software development context. The explore phase can be

timely unattached to the previous phases of Mobile-D and also overlap with the

0 Iteration phase. It is important for setting the grounds for controlled

implementation of the software development product, especially pertaining to

issues related to product architecture, software development process and

environment selection. Different stakeholder groups are needed to provide their

expertise in this critical step.

Initialize

The purpose of this phase pattern is to enable the success of forthcoming

project phases by preparing and verifying all critical development issues. In the

end, all are in full readiness for implementing options selected by the customer. Productionize

At the production phase, the required functionality is put together in the

product by applying an iterative and incremental development cycle.

Stabilize

The purpose of the Stabilize phase pattern is to ensure projects

implementation quality.

System test & fix

The System Test & Fix aims at controlling the produced systems

performances. This is achieved by verifying the correct implementation of

customer defined functionality, providing the project team continuous feedback

on the systems functionality, and fixing the found defects.



45/68

5

2

20

13


Figure3: Mobile-D phases

D-Mobile-D methodology evaluation

The mobile-D methodology advantages and disadvantages are listed

below.

Advantages Mobile-D is well adapted to mobile software development in small

teams.

Able to satisfy the changing needs of users through short iterations

(phases initialize productionize, stabilize).

Pair programming for each iteration working day step, is very

efficient.

Software documentation is complete.

Every step is clear and detailed.

Easy to monitor project progress



46/68

5

2

20

13


Every step task is detailed.



47/68

5

2

20

13


Disadvantages

Mobile-D is designed to fit the small system developed by a small team.

Thus, it cannot be adapted to a complex business system (ex: M-commerce) in

the future phone mobile industry. Besides, there are still no teacher or set

guidelines for the technologies and tool selection for mobile software

development.

ConclusionThroughout this chapter, I began by outlining the appropriate customized

monitoring solution needs analysis that the system must provide the user with,

followed by the functional and non-functional requirements and different use

cases and sequence diagrams possible to understand the principle of operation.

This study has helped resolve some problems related to the development of the

application.

The next chapter will focus on the design phase.



48/68

5

2

20

13



Chapter IV Design Phase

Introduction

Objects sequence diagram

Activity Diagram

Class diagram

Conclusion


49/68

5

2

20

13


4.Design Phase

Introduction

We dedicate this chapter to the presentation of the architecture and

design of our project. We begin by describing the architecture of our application

through different dynamic views through the sequence diagram objects, and a

diagram of global activities and a class diagram that will take a look at the

different project entities.

a- Objects sequence diagram

For a comprehensive view of the sequential main features of our system,

we present this system sequence diagram in the figure below:

Figure17: Objects sequence diagram

Ce diagramme montre linteraction de faon squentielle entre les 3

Objets principaux du scnario, ces objets reprsentent les classes principales de

lapplication.

A first intervention must be set by the user, so that the applicationinitializes.



50/68

5

2

20

13


b- Activity Diagram

In this section we present the activity diagram associated with the entire

system.

According to this diagram we see that our system is multitasking, it also

distinguishes several activities are triggered automatically without human

intervention, it also distinguishes it lacks many alternative scenarios and this is

because we try to avoid any human presence around the application



51/68

5

2

20

13


Figure18: Activity diagram

c- Class diagram



52/68

5

2

20

13


The class diagram is a static diagram. It represents the static view of an

application, it is not only used to visualize, describe and document the various

aspects of a system, but also for the construction of executable code of the

software application. It describes the attributes and operations of a class and also

the constraints imposed on the system.

Figure19: Class diagram

The class diagram of our project shows two main parts, each representing

a separate application.

The construction of the first frame passes all the verification and conversion



53/68

5

2

20

13


bytes different fields. These frames are then sent and responses are received and

analyzed to be whether to proceed or not recording.

ConclusionDetailed design has allowed us to have a more accurate view on the

subject and a deeper understanding of the tasks. It also leads to provide software

needed to achieve the goal.

We have tried throughout this chapter to properly present the different

conceptual diagrams of the project. These diagrams will be the basis on which

we will achieve our project; this phase will be detailed in the next chapter.



54/68

5

2

20

13



Chapter V Implementation

Introduction

I. Hardware environment

II. Work Environment

III. Screenshots and results

Conclusion


55/68

5

2

20

13


5.Implementation

Introduction

This chapter is the last part of the report of our project graduation. It aims

to showcase the work completed.

In this part, we will describe the implementation process of the

application we are developing. We will specify our development environment,

hardware, developing tools and we will present some screenshots of our

application.

I. Hardware environment

1- Development tool

To develop our application we used a Toshiba laptop computer with an i5

processor core and 4Go Ram memory running on Windows Seven Pro Edition.

2- Test device

we did our tests on what is called NetBox which is an electronic device

powered by Android made for generally for TV entertainment, this box is

characterized by 1Ghz processor, 256 Mb Ram, 4 Go flash memory for storage

and powered by Android 4.0



56/68

5

2

20

13


Figure20: the shape of the used device

II. Work Environment

1- Eclipse

Eclipse is a multi-language development environment with a integrated

development environment (IDE) and an extensible plug-in system. It is written

primarily in Java and can be used to develop applications in Java and, by means

of various plug-ins, other programming languages, including Ada, C, C + +,

COBOL, Perl, PHP, Python, Ruby.

2- SDK Android

Android SDK is essential to develop Android, which is a development kit

created to be integrated in an IDE, it offers a set of tools necessary for the

development and testing as ADT, the compiler, the emulator, the DDSM ...

3- Photoshop

Photoshop is an editing software, processing and computer-aided drafting

published by Adobe. It is mainly used for processing digital photographs, but

also used for imaging and design. It is used in our application to create some

graphical elements like the overall design of the interface and borders and other

needs.

4- SDK Google Drive

Drive SDK, developers proposed by Google, gives a group API client

libraries, specific examples of language and documentation to facilitate the



57/68

5

2

20

13


development of applications that integrate with Drive. The basic functionality is

to download or to mount files in Google Drive.

5- Modbus SlaveModbus Slave is simulation software. It can simulate up to 32 slaves.

Each open in this window simulator can be configured to represent the data in

the same or different way for all slaves. Modbus Slave supports all Modbus

functions.

Figure21: Modbus slave interface

6- WireShark

WireShark is a powerful tool that captures the packets

through an interface (sniff) and analyze catches looking case or

to perform statistics.

WireShark can be used to analyze network or possibly

determine if a machine is infected by analyzing the connections

made by malware. WireShark allows us to verify the success of



58/68

5

2

20

13


the communication between the entities involved in the

exchange.

Figure22: WireShark interface

III. Screenshots and results

This section exhibits different interfaces for our application.

//Screenshots section is not ready yet due to graphical editing of the

interfaces

Conclusion

In this chapter, I first presented the work environment and required tools

for our application. I then illustrated the result of my work with screen printed

key interfaces of the application.



59/68

5

2

20

13


General Conclusion

At the end of this work, we believe that this project has been beneficial,

as it allowed us to consolidate our efforts and skills in designing an innovative

application, which will be useful to improve the combination of industrial

technology and Android world.

During this project, we first conducted research on the state of telephony

services in the world in order to identify the users needs. We then determined

the main objectives and features to integrate into a mobile application that better

meets our subjects requirements.

In addition, we have learned through this experience to organize our

work using the mobile-D methodology, which in our case was an efficient way

to realize this project and upgrade this work to a professional level.

We believe that the objectives were largely achieved. However, and like

any other work, this project does not claim perfection.

In conclusion, This experience was very rewarding and important

because it marked the end of the engineering cycle and allowed us to face the

responsibilities are those of an engineer: to meet deadlines, stress and constraints

of working in a research environment and innovation.



60/68

5

2

20

13


List of Abbreviations

API : Automate programmable industrial.

API : Application programming interface

ASCII : American standard code for information interchange.

CRC : Cyclic redundancy check.

ID : identifier.

IDE: Integrated development environment

IP : Internet protocol.

MB : Modbus.

NDA : Non-Disclosure Agreement

OSI : Open systems interconnection.

PLC: Programmable Logic Controller

RTU : Remote terminal unit.

SCADA : Supervisory Control And Data Acquisition

SDK : Software development kit.

TCP : Transmission control protocol.

HMI / MMI: Human Machine Interface / Man-Machine Interface

http://en.wikipedia.org/wiki/Application_programming_interfacehttp://www.automation.siemens.com/mcms/automation/en/human-machine-interface/pages/default.aspxhttp://www.automation.siemens.com/mcms/automation/en/human-machine-interface/pages/default.aspxhttp://en.wikipedia.org/wiki/Application_programming_interface


61/68

5

2

20

13


BIBLIOGRAPHIE

[1] MODBUS APPLICATION PROTOCOL SPECIFICATION

V1.1b - Modbus IDA - December 28, 2006 - www.modbus.org

[2] MODBUS APPLICATION PROTOCOL SPECIFICATION

V1.1b3 Modbus IDA - April 26, 2012 - www.modbus.org

[3] MODBUS MESSAGING ON TCP/IP V1.0b Modbus IDA - October 24,

2006 http://www.modbus -ida.org.

[4] MODBUS over serial line specification and implementation guide V1.0

Modbus IDA February 12, 2002 - www.modbus.org

[5] MODBUS Protocol Modbus IDA November 1, 2000

[6] Google. Android Open Accessory Development Kit.Developer.android.com.

[En ligne] http://developer.android.com/guide/topics/connectivity/usb/adk.html.

[7] http://www.goopilation.com/2012/09/android-alibaba-acer-compatibilite.html

.

[8] http://searchcio-midmarket.techtarget.com/definition/SCADA

[9] http://ecmweb.com/content/industrial-ethernet-infrastructure-could-top-1-

billion-2011

[10] http://www.mesures.com/actualites/ethernet-industriel-quatre-protocoles-

dominent-le-marche-5447.html

Annex

Lifecycle of an Android application



62/68

5

2

20

13


Figure: Lifecycle of an Android application

Description of the function codes



63/68

5

2

20

13


Read Coils 01 (0x01)

This function code is used to read from 1 to 2000 contiguous status of

coils in a remote device. The Request PDU specifies the starting address, i.e. theaddress of the first coil specified, and the number of coils. In the PDU Coils are

addressed starting at zero. Therefore coils numbered 1-16 are addressed as 0-15.

The coils in the response message are packed as one coil per bit of the data field.

Status is indicated as 1= ON and 0= OFF. The LSB of the first data byte contains

the output addressed in the query. The other coils follow toward the high order

end of this byte, and from low order to high order in subsequent bytes.

The state diagram in the figure below describes the generic treatment of a

wrong answer using function code 01, and almost all the read functions.

Figure14: Read Coils state diagram

Read Discrete Inputs 02 (0x02)

This function code is used to read from 1 to 2000 contiguous status of

discrete inputs in a remote device. The Request PDU specifies the starting

address, i.e. the address of the first input specified, and the number of inputs. In

the PDU Discrete Inputs are addressed starting at zero. Therefore Discrete inputs

numbered 1-16 are addressed as 0-15. The discrete inputs in the response



64/68

5

2

20

13


message are packed as one input per bit of the data field. Status is indicated as

1= ON; 0= OFF. The LSB of the first data byte contains the input addressed in

the query. The other inputs follow toward the high order end of this byte, and

from low order to high order in subsequent bytes.

The description of specific fields of function code 02 request, response

and error frames is shown in the following tables respectively.

Request frame size

*N = Quantity of Inputs / 8 if the remainder is different of 0 N = N+1Response frame size

Error frame size

Read Holding Registers 03 (0x03)

This function code is used to read the contents of a contiguous block of

holding registers in a remote device. The Request PDU specifies the starting

register address and the number of registers. In the PDU Registers are addressed

starting at zero. Therefore registers numbered 1-16 are addressed as 0-15. The



65/68

5

2

20

13


description of specific fields of function code 03 request, response and error

frames is shown in the following tables respectively.

Request frame size

Response frame size

Error frame size

Read Input Registers 04 (0x04)

This function code is used to read from 1 to 125 contiguous input

registers in a remote device. The Request PDU specifies the starting register

address and the number of registers. In the PDU Registers are addressed starting

at zero. Therefore input registers numbered 1-16 are addressed as 0-15. The

description of specific fields of function code 04 request, response and error

frames is shown in the following tables respectively.

Request frame size

Response frame size



66/68


67/68

5

2

20

13


addressed as 0. The description of specific fields of function code 06 request,

response and error frames is shown in the following tables respectively.

Request frame size

Response frame size

Error frame size

Write Multiple registers 16 (0x10)

This function code is used to write a block of contiguous registers (1 to

123 registers) in a remote device. The requested written values are specified inthe request data field. Data is packed as two bytes per register. The normal

response returns the function code, starting address, and quantity of registers

written. The description of specific fields of function code 16 request, response

and error frames is shown in the following tables respectively.

*N = Quantity of Registers

Request frame size



68/68

20

13


Response frame size

Error frame size

bilel modifications 1

Documents