REMOTE MONITORING DISTRIBUTED SYSTEMS

The new generation of control systems

Víctor Ruiz Valera, Mario de la Cruz Ortiz, Rafael Herradón Díez and Florentino Jiménez Muñoz

Departamento de Ingeniería Audiovisual y Comunicaciones (DIAC), Universidad Politécnica de Madrid, Spain

Keywords: Internet services, Distributed systems, Parameters Control, Data acquisition systems.

Abstract: Nowadays, it is increasingly necessary and interesting to measure

and control the levels of some parameters.

This research and project work has been developed with the aim of creating a data acquisition and

monitoring distributed system that allows the users to monitor and control easily, powerfully and flexibly

any parameter interesting enough to be studied for later monitoring in real time. At the same time, it is also

intended to make the system accessible to the general public and citizens, by using the most implanted and

widespread network: Internet and the TCP/IP networks. As a result we present an application offering a

“measurement transport layer” providing several services that will work with any kind of parameter.

1 INTRODUCTION

Nowadays, it is more and more necessary and

interesting to measure and control the levels of some

parameters. These measurements can be used in two

ways. On the one hand, we consider real time

measurement where the most interesting part is to

control discrete time value of the parameter. On the

other hand, we deal with the storage of all these

measurements in databases with the purpose to make

later analysis about the parameter time evolution.

Our research and projects have been developed

with the

purpose of creating a data acquisition and

monitoring distributed system that allows the users

in an easy, powerful and flexible way, to monitor

and control any parameter that may be interesting to

study for monitoring in real time and later analysis.

At the same time, it is also intended to be able to

make the system accessible to the general public and

citizens, by using the most implanted and

widespread network: Internet and the TCP/IP

networks.

Due to the growing proliferation and installation

f systems that work with electromagnetic

emissions, we decided to apply the system to

electromagnetic fields measurements because lately

the society is very worried about it. This concern is

owing partly to the ignorance of the consequences

that radiant systems and its emissions can have in

our health and on the other hand, to the necessities

of controlling the emissions in the electromagnetic

spectrum and their influence or interference with

other systems.

The system is a distributed application based on

sev

eral main servers providing support to the

measurement equipment located in the monitored

area, and to the users that are going to view and

request the information and data captured with the

measurement equipment. These measurement

equipments can be static or mobile travelling around

the zones that we want to monitor. The monitoring

application will allow to know in real time the

measurement of the electromagnetic field and

spectrum at a concrete instant and place. In addition,

the application will also show a series of statistics

and possible alarms when the measurement levels

overcome certain thresholds. And all these features

work on a web environment, and are accessible and

usable from a computer with TCP connectivity.

2 SYSTEM DESCRIPTION

The basic idea of the system is to have distributed

measurement equipment that capture measurements

and send them to data centres continually through a

communication channel, typically Internet. The

distributed measurement equipment can be systems

specifically designed to do capturing and sending

functions, or can be commercial measurement

equipment connected to a computer containing

specific software to do control and measurement

sending tasks. Obviously there must be a channel

264

Ruiz Valera V., de la Cruz Ortiz M., Herradón Díez R. and Jiménez Muñoz F. (2005).

REMOTE MONITORING DISTRIBUTED SYSTEMS - The new generation of control systems.

In Proceedings of the Second International Conference on Informatics in Control, Automation and Robotics - Signal Processing, Systems Modeling and

Control, pages 264-269

DOI: 10.5220/0001177302640269

 SciTePress

from the each piece of distributed measurement

equipment and the system data centre so that they

are communicated.

The measurement equipment locations can be

static or mobile. In case the equipment is mobile,

they can have a coupled GPS system that will allow

us to know their position in each instant. So that, in

the server each measurement will be stored with the

time and position in which it was captured.

The system core is the database, which stores

and registers all the information; and the server, that

coordinates and manages the accesses to the

database, like an access point through which all the

other elements are interconnected. The server

handles the connections and requests from

measurement equipments, users and administrators.

To be able to assist all the tasks correctly, the Server

is composed of several subservers for each function

that dialogue to each other to coordinate their

actions.

The users access to the system through a web

interface in any browser. They can visualize the

available measurement equipment, their

measurements values, their position on a digital

map, to monitor certain areas, their temporal and

position evolution, statistical data, etc; and

everything in real time, thanks the web embedded

Java applications or applets, with a graphic interface

and forms.

The Administrator Users can also access to the

system to configure and manage the Server, the

measurement equipments, etc, from any place

through web interface with embedded applications

and forms.

The interconnection between each one of the

blocks (clients, servers and database) is over

TCP/IP. The rest of the elements are located on this

transport layer and they communicate to each other

and request services to the servers through different

protocols. The final purpose of the system is to

create a layer that allows us to exchange any kind of

measurement, as well as to store and consult them.

2.1 Election of technologies for

system implementation

Possibly, the most appropriate programming

language for the development of this system is Java.

Java has some important characteristics that make it

especially attractive: strongly oriented to intra and

inter network applications, multi-platform, client-

server applications, and distributed applications in

LANs and Internet, besides providing enough

reliability to the applications.

For information exchange between client and

server processes, the RMI (Remote Method

Invocation) package has been used, and for access

to the information stored in the database the JDBC

(Java DataBase Connectivity) package is used; and

finally, for user-application interaction it is needed a

tool to create user's graphic interfaces. This tool is

the SWING package, which allows GUIs

development (windows, buttons, labels, dialogs,

menus, images, etc).

2.2 System Architecture

2.2.1 Introduction

The designed system is a distributed application

based on the client-server model and implemented in

Java programming language, following distributed

objects techniques. The communication between

distributed objects is over TCP/IP protocols. In

Figure 2 you can see the global architectural view of

the system.

ure 1: S

stem Descri

tion.

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265

Figure 2: System Architecture

2.2.2 The server and the database, brains of

system

In our system, data are the most important thing,

because the main function of the system is data

collecting and data offering. So we decided to use a

relational database manager system software that

supports a huge volume of information. MySQL

provides a robust solution to users with powerful

multi-user tools, interface access to the data

normalized through (Structured Query Language)

SQL language, multi-threaded. It is a very quick,

robust and easy to use language, apart from being

open source.

As important as the database, it is the Java

Server, in charge of controlling all the interactions

with the database. The Server has been divided into

three small servers, with the purpose to give service

and assist to each one of the client applications of

each one functionality area.

• Measurements Server: it gives support to the

remote measurement equipment of the Client

Application in the Measurement Equipment

Control Area. The server subscribes the

measurement equipment in the database

(indicating all their characteristic data), stores the

measurements, alarms and configuration,

unsubscribes the equipment, indicates the state in

which the equipment is, etc. Also, if there are

errors in the connections with measurement

equipment, the server is able to re-establish the

connections automatically when the network

service will be up again.

• Users Server: gives support to the Remote

Measurement Equipment Monitoring Applet on

the web client in the User Area. The server will

monitor the geographical situation of the

equipment and the measurements that it is

capturing in real time, wherever it is. It requests

to the database to obtain a list with the current

data and measurements of each one of the

connected meters, in a periodic and constant

interval, to view the measurement in almost real

time.

• Administrators Server: gives support to

the Remote Control Applet on the web client in

the Administration Area, where an authorized

administrator can control remote equipment

connected to the Server, and manage the system.

2.2.3 Client Applications

The access to the server can be different depending

on which client application is accessing to the

server. There are three different working planes or

functional areas:

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• Measurement Equipment Control Area:

it is a Java application that allows to install and

configure a measurement equipment, and

subscribe it on the system, control the equipment,

establish measuring parameters such as time

length, capture and sending data interval,

measurement type, equipment position, etc. Also

it allows visualising the measurements captured,

and the alarms indicators. It will be connected,

through Internet, to the Measurement Servers that

you indicate, being able to be connected and to be

sending data simultaneously to several servers.

Figure 3: Served Pages Schema

• Users Area: offers consulting services to

the users, like real time monitoring applet, or

some forms to request statistical graphics of the

stored information. The first service is an applet

composed of a panel for the geographical

localization of the equipment and another panel

for the real time monitoring of the measurements

captured by the located meters. This application

is connected the Users Server with an RMI

connection to upgrade the data in almost real

time. With the consultation forms, the user can

curse petitions to the Statistical Graphic Server

about the stored information. The return result

will be html pages with the data in graphical

format, containing the measurements obtained by

the selected meter during the specified time

period.

• Administration Area: it offers

administration services to authorized

administrators users. In this area we can make

remote control of the measurement equipment

that is subscribed in the system and of other

managing tasks like the database administration,

etc. For Equipment Remote Control it offers an

applet that is connected with the Administrators

Server through a RMI connection to obtain the

list of current subscribed equipment. In this way,

the configuration parameters can be viewed and

remotely controlled, without needing anybody in

the place where the equipment is located.

2.2.4 Other elements

To give support to all the elements of the

architecture, it is necessary some other elements like

web servers, Apache in this case, dynamic pages

scripting technologies, for example PHP, and

application servers or servlet engines like it can be

Apache Tomcat.

2.3 System Capabilities

2.3.1 Measurement Equipment Access

Capabilities

In the start menu, you can add the measurement

equipment to the system and configure them

correctly. For each piece of equipment we can define

if the equipment is static or mobile, position (long,

lat, alt and location description or GPS option),

connection port, measurement parameters like

interval between samples (s), measurement period,

type of parameter (the value in the discrete instant or

the average along the interval) and the server list

where we want to connect and the measurements

that will be sent.

ure 4: Confi

and Monitor E

ment Panels

For each added equipment, a panel appears with

a tab and the tools to control the equipment locally.

In the panel there are some bars with the values of

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the measurements in real time (E and H), alarm

indicators (registered value, date, time), state of

connections with servers, the interval, and real time

(line) graphics with the E and H representation.

We can change and update all the explained

parameters and of course, we can delete equipment

from the system.

2.3.2 User Access Capabilities

The user access provides these capabilities:

• Real Time Monitoring: It is the embedded

application in a web page dedicated to real time

monitoring of the measurements that the

distributed equipment in different areas are

sending to the server. This applet is continuously

requesting to the Users Server the last version of

the list with the equipment and its measurements,

to be represented on the screen. At top there is a

map where the applet represented the

geographical information of the equipment, and

at bottom there are some panels with the

measurement values in real time, meters bars,

alarms indicators and other information.

• DB Information Request: using web forms, a

user can request and extract information from

database. For example, the equipments list, data

historical, alarms historical and much more.

• Statistical Graphics Generator: using web

forms we can obtain all the information but in a

statistical graphic format, with any parameter and

in the range of specified time.

2.3.3 Administrator Access Capabilities

The administrator can access to the system control

options but must be previously authenticated with

• Remote Control: it is an embedded applet

on a web page that permits to make remote

control on any equipment from any place. This

applet is refreshing continuously the

measurement equipments list through a RMI

connection with the Administrators Server, which

obtains the information from the database.

Figure 5: Real Time E and H measurements, in

Graphical Format

• Database administration: the

administrator user has permission to manage the

database with tools like PHPMyAdmin, a web

interface database managing system.

3 CONCLUSIONS AND

POSSIBLE APPLICATIONS OF

SYSTEM

At first, about electromagnetic emissions theme, we

cannot affirm that are dangerous for human (when

the levels are down of limits allowed by laws)

because doesn’t exist evidences about it. But we

cannot neither say that are innocuous because there

are not enough studies about it and we don’t know

their long time effects. So it is recommended to

protect sensible zones like schools, hospitals, etc.

One of the final objects of project is to make a

“measurement transport layer” providing several

services that will work with any kind of parameter,

and can be used to create a lot of different

measurement system with the same philosophy.

Some possible cases to use this kind of systems

are:

• Investigation groups that need to work from

different places in the world, but they need

to work with the same data simultaneously.

For example, a scientist in Barcelona that

needs other opinion about some

measurements, but the other person is in

Figure 6: Real Time Monitoring Application and

panel detail

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Sidney. Both can view in their browsers the

same data at the same time.

• Creation of data repositories to make later

analysis. For example, to work with

parameters that currently we don’t know

enough, and to have a lot of data to research

later if these measurement levels are related

with others events or facts.

• The control of certain parameters that are

important to the general public and citizens,

like for example contamination parameters,

or traffic report data. For example, it is

possible to use the system with “cars

counters” and offer to the citizens a map

with traffic congestion information in real

time.

There are a lot of more possible applications for

this kind of systems, and the only limit is your

imagination.

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