FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention - A SYSTEM AND A METHOD FOR SECURED
COMMUNICATION IN A TOTALIZER UNIT

2. Applicant(s)
(a) NAME :
(b) NATIONALITY :
(c) ADDRESS :

LARSEN & TOUBRO LIMITED
An Indian company
L & T House, Ballard Estate, Mumbai 400 001, State of Maharashtra, India

3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed :

FIELD OF THE INVENTION
The present invention relates to a system for secured and tamper proof communication in a totalizer unit. More particularly, the invention is concerned about a secured data communication system between pulse generator and a totalizer unit such that counting in totalizer is totally immune from external intervention.
The invention also relates to a method of integrating pulse generator system of counting the pulses or amount of fluid dispensed and method for operation of tamper proof totalizer.
BACKGROUND AND THE PRIOR ART
Totalizers are used to count total volume of fuel dispensed. At any fuel station, the totalizer is read at the starting and at the end of the shift and the amount equivalent to the difference in the readings is collected from the attendants.
Any electromechanical/electronic counter accepts pulses fed by the microcontroller and increase the count accordingly. Due to the simple TTL/CMOS interface between controller unit and the counter, the system can be easily defaulted and prone to tampering by simple methods/manipulations. Thus there exists a need for a a system for secured and tamper proof communication in a totalizer unit.
EP1858144 discloses an intelligent power module for providing power to a fluid flow totalizer, the module comprising: a processor configured to generate a signal that represents a measure of a flow of a fluid in response to a signal received from a fluid flow sensor; a plurality of supply circuits, each


supply circuit comprising at least one energy storage cell in series with a unidirectional flow element to substantially limit current flow through each of the supply circuits to a preferred direction; and a switched mode power supply comprising an input coupled to draw power from any of the supply circuits and an output to deliver power to the processor, the power supply providing a voltage boost when a voltage at the input is lower than a desired voltage at the output. It was not known that the tampering of the totalizer could be prevented by a unique method of integration of pulse generator with totalizer using a detector circuit.
US3578955 discloses a totalizer that accepts a DC input signal having a magnitude proportional to one process variable, the measuring circuit converting the input signal to a train of pulses having a repetition rate accurately reflecting the magnitude of the input signal. When a second variable is also involved, a multiplication is achieved by stopping the flow of pulses for certain periods of time so that the product of the two variables is indicated in both the rate indication and the total number of pulses counted. It was not known that the tampering of the totalizer could be prevented by a unique method of integration of pulse generator with totalizer using a detector circuit.
Any tampering with the totalizer coil or cable will produce false reading of dispensed fuel volume, which will directly affect the business. Therefore there is a need to prevent tampering of totalizer and unauthorized access to totalizer or the communication channel between micro-controller and the totalizer. The system of the present invention can also be used in other areas like electronic voting/polling machine, pulse counters, and the like. This list describing totalizer applications is non exhaustive and there are many other


applications. There is also a need to provide authenticity in pulse generators.
The present inventors have found that the problem of tampering in fuel dispensing pumps can be prevented providing a uniquely designed communication circuit/block between pulse generator and the totalizer units of the fuel dispensing pumps.
OBJECTS OF THE INVENTION
Accordingly, one object of the present invention is to overcome the problems/disadvantages prevailing in the prior art.
Another object of the present invention is to provide a system for tamper-proofed communication in totalizers used in fuel dispensing pumps.
Another object of the present invention is to provide counting in the totalizer totally immune from external intervention.
Yet another object of the present invention is to provide security against shorting electro-mechanical totalizer coil.
Yet another object of the present invention is to provide security against opening electro-mechanical totalizer coil.
Yet another object of the present invention is to provide security against removing supply cable or fraudulent pulses given by unauthorized user.


Yet another object of the invention is to bring totalizer unit under the total asset management system by identifying the unit by its unique 64-bit address
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is
provided a system for secured communication in a totalizer
unit used in fuel dispensing pumps, said system comprising:
micro-controller unit;
plurality of tamper-proof circuits operatively connected to
said micro-controller by means of 1-wire communication
dataline, said tamper proof circuits being connected at one
end to the micro-controller and at the other end to clock
inputs of the totalizer wherein said tamper proof circuit
comprises
1-wire communication IC circuit receiving data information
from said micro-controller;
totalizer coil driving circuit with its input side connected
to said IC circuit, said driving circuit adapted to receive
output from said IC circuit; and
detecting circuit connected to the totalizer coil driving
circuit, said detecting circuit adapted to detect short
circuit in coils, open circuit in coils, power supply and the
like
thereby preventing fraudulent in count in the totalizer.
Another aspect of the present invention is to provide a method of integration of pulse generator with totalizer for use in fuel dispensing pumps, said method comprises the steps of: identifying serial number of totalizer by means of 1 wire communication circuit;


comparing said identified serial number of totalizer to a predetermined value stored in micro-controller unit; and authenticating said totalizer.
The other objects and advantages of the present invention will be apparent from the detailed description and the description provided hereinbelow with reference to the accompanying figures.
DETAILED DESCRIPTION OF THE INVENTION
The invention relates to a system and method of integration of pulse generator with totalizer using a circuit to prevent fraudulent in counter measuring systems. Secure communication channel between pulse generator and the totalizer makes the electro-mechanical totalizer tamper-proof.
The master device or microcontroller initiates and controls all activities on the network bus. The bus master acts as a protocol and timing interface between a personal computer or microcomputer and the 1-Wire network. Both the bus master and all slave devices internally act as transceivers. These are devices that can both send and receive data on a single data line. One can think of this single communications line as a single lane road, where traffic takes turns, first going one way, then the other. Thus data can flow in either direction, but only one direction at a time (half duplex operation). Data transfers are sequential with the least significant bit of a byte being transmitted first, over a single pair of wires, a data and a ground return line. Synchronizing of the devices is handled by the 1-Wire data protocol. This allows tight control of the data bus because the protocol allows no slave to speak unless requested by the master, and then communication is only


allowed between the selected slave and the bus master; no communication is allowed slave to slave.
1-Wire communications takes place digitally (on or off logic states), over a wire cable (typically twisted pair). The network is defined with an open drain (wired-AND) master/slave multi-drop architecture that uses a resistor pull-up to a nominal 5 Volt supply at the master.
Tamper proof electro-mechanical totalizer of present invention can be used in many areas like fuel dispensing pumps, electronic voting, pulse counters, automatic packaging of electronic components, control of the number of shots for spot welding machines. The present invention can be used in areas like electronic vote counting, where counter should be able to count pulses only from authentic pulse generator.
Another embodiment of the present invention describes a method of integration of pulse generator with totalizer for use in fuel dispensing pumps. Serial number of totalizer is identified by means of 1 wire communication circuit and then compared to a predetermined value stored in micro-controller unit followed by authentication of the totalizer. Authentication of totalizer is carried on by checking serial number, disconnection of supply, coil open and / or coil short and the like.
Advantages :
• Small and simple circuit


• Application of this circuit is not restricted to totalizers. It can be used anywhere where such tamper-proof secure communication is required
• Low cost around $1.5
• Unique Identification of circuit
• Asset management is possible.
• This circuit gives a tight control to the system.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 illustrates a schematic block diagram of the system of the present invention.
Figure 2 Illustrates short stub topology
Figure 3 Illustrates star topology
Figure 4 illustrates detailed schematic circuit diagram of the system of the present invention.
Figure 5 illustrates flow chart showing secured communication in the totalizer.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 shows micro-controller unit (1), tamper proof circuit (2) and 1 wire dataline (3).
As shown in the circuit diagram, circuit can be divided into three parts. They are:


1. 1-W communication IC circuit
2. Totalizer coil driving circuit
3. Circuit to detect coil short, coil open, power supply detection
1-W communication IC circuit:
The whole network works on 1-W communication protocol (shown in figure 1) . Data from microcontroller is given to this IC. This IC has unique 64-bit identification number. This gives unique identification to entire circuit. This IC is used for 1-W communication. The output from this IC is given to Totalizer coil driving circuit.
Totalizer coil driving circuit:
It consists of transistor Ql, Q2 (reference figure 4), and biasing resistors. Generally totalizer uses a coil for its counting mechanism. 1-W IC cannot supply such high value of current. So two NPN transistors Ql & Q2 are used back to back to increase current driving capacity of the pin. We can replace these two NPN transistors by one PNP transistor so as to reduce number of components.
Circuit to detect coil short, coil open, power supply detection:
It consists of transistors Q3, Q4 (reference figure 4), and biasing resistors. Here transistor Q3 is used as a switch. The biasing arrangement is made in such a way that it will


switch ON only when coil is driven. In turn it will switch ON
only when power supply is present. So a feedback is given to
IC and in turn to microcontroller to detect whether coil is
driven or not. Similar to Totalizer coil driving circuit, we
can replace two PNP transistors by 1 PNP transistor so as to
reduce number of components.
The invention has been described in a preferred form only and many variations may be made in the invention which will still be comprised within its spirit. The invention is not limited to the details cited above. The components herein described may be replaced by its technical equivalence and yet the invention can be performed. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.


WE CLAIM
1. A system for secured communication in a totalizer unit
used in fuel dispensing pumps, said system comprising:
micro-controller unit;
plurality of tamper-proof circuits operatively connected to said micro-controller by means of 1-wire communication dataline, said tamper proof circuits being connected at one end to the micro-controller and at the other end to clock inputs of the totalizer
wherein said tamper proof circuit comprises
1-wire communication IC circuit receiving data
information from said micro-controller;
totalizer coil driving circuit with its input side
connected to said IC circuit, said driving circuit
adapted to receive output from said IC circuit; and
detecting circuit connected to the totalizer coil driving
circuit, said detecting circuit adapted to detect short
circuit in coils, open circuit in coils, power supply and
the like
thereby preventing fraudulent in count in the totalizer.
2. System as claimed in claim 1, wherein the 1-wire communication protocol comprises 64 bit identification number.
3. System as claimed in claim 1, wherein the totalizer coil driving circuit comprises at least two transistors, preferably NPN transistors adapted to increase current driving capacity of the circuit.


5. System as claimed in claims 1 to 4, wherein the totalizer coil driving circuit further comprises biasing resistors.
6. System as claimed in claim 1, wherein the detecting circuit comprises at least two transistors.
7. System as claimed in claim 1, wherein the detecting circuit further comprises biasing resistors arranged such that the detecting circuit will switch ON only when the coil is driven.
8. A method of integration of pulse generator with totalizer for use in fuel dispensing pumps, said method comprises the steps of:
identifying serial number of totalizer by means of 1 wire communication circuit;
comparing said identified serial number of totalizer to a predetermined value stored in micro-controller unit; and authenticating said totalizer.
9. Method as claimed in claim 9, wherein step of authentication of totalizer comprises serial number checking, checking for disconnection of supply, coil open and / or coil short and the like.
10. A system and a method for secured communication in a totalizer unit used in fuel dispensing pumps as substantially herein described and illustrated with reference to accompanying figures.
Dated this 28th day of March 2008



ABSTRACT
A SYSTEM AND A METHOD FOR SECURED COMMUNICATION IN A TOTALIZER UNIT
The present invention relates to a system for secured communication in a totalizer unit used in fuel dispensing pumps. The system comprises micro-controller unit (1), plurality of tamper-proof circuits (2) connected to the microcontroller by means of 1-wire communication dataline (3) . The tamper proof circuits 1-wire communication IC circuit, totalizer coil driving circuit with its input side connected to said IC circuit and detecting circuit connected to the totalizer coil driving circuit to detect short circuit in coils, open circuit in coils, power supply and the like thereby preventing fraudulent in count in the totalizer. The invention also relates to a method of integration of pulse generator with totalizer for use in fuel dispensing pumps. The method comprises identifying serial number of totalizer by means of 1 wire communication circuit and comparing the identified serial number of totalizer to a predetermined value stored in micro-controller unit and authenticating said totalizer.
Figure 1