FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION (See section 10 and rule 13)
1. TITLE OF THE INVENTION:
System for Modbus Communication in Circuit Breakers
2. APPLICANT:
(a) NAME: Larsen & Toubro Limited
(bj NATIONALITY: Indian Company registered under the
provisions of the Companies Act-1956,
(c) ADDRESS: LARSEN & TOUBRO LIMITED,
L&T House, Ballard Estate, P. 0. Box: 278, Mumbai 400 001, India
3. PREAMBLE TO THE DESCRIPTION:
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

System for Modbus Communication in Circuit Breakers
Field of the invention
The present invention relates to Modbus communication in circuit breakers, and more particularly, the present invention relates to the Modbus communication in circuit breakers for remote monitoring an electrical installation and diagnosing any abnormality if need arises.
Background of the invention
Modbus is a single master/multiple slave network communications protocol originally defined by Modicon for factory floor automation equipments. Modbus remote terminal unit (RTU) is an open, serial communication protocol based on the master-slave architecture. MODBUS can be implemented extremely easily on any serial interfaces. MODBUS has two fundamental communication mechanisms, i.e. Query-Response (Polling). In this mechanism, the master sends a request frame to any station and expects a response frame from that particular station. Another mechanism is a broadcast mechanism in which the master sends a command to all stations on the network. This mechanism executes the command without acknowledgment, and the message frames allow process data [input/output data) to be written or read either individually or in groups. There are two types of serial transfer i.e. RTU and ASCII. Modbus is often used to connect a supervisory computer with a remote terminal unit (RTU).
Specifically, MODBUS is used on various transmission media. Implementation on the RS485 physical bus, a shielded, twisted-pair cable with terminating resistors, is widespread.

In the existing circuit breakers, Modbus is used for remote reading of the metered values, applying system/protection settings, and the like. However, the existing Modbus communication in the circuit breakers uses wires for communication and have high power consumption due to use of high frequencies for communication.
Accordingly, there exist a need to provide Modbus communication in circuit breakers which overcomes drawbacks of the prior art.
Objects of the invention
An object of the present invention is to reduce use of power during Modbus communication in circuit breakers.
Another object of the present invention is to provide convenience and freedom from wires during Modbus communication in circuit breakers.
Summary of the invention
Accordingly, the present invention provides a system for Modbus communication in circuit breakers. The system comprises an electronic trip unit capable of communicating wirelessly through Sub-Giga module with anyone of a switch board panel, and PC-HMI based control at remote location. Specifically, the internal communication between the electronic trip unit and the Sub-Giga Module is achieved using Inter-Integrated Circuit, I2C.
Typically, wherein the wireless communication between the electronic trip unit with anyone of the switch board panel, and the PC-HMI based control is achieved within a distance of 60 meters with concrete obstacles and 150 meters line-of-sight.

Brief description of drawings
Other features as well as the advantages of the invention will be clear from .. the following description.
In the appended drawings:
Figure 1 shows a block diagram of a Modbus communication in circuit breakers, in accordance with the present invention.
Detailed description of the invention
For a thorough understanding of the present invention, reference is to be made to the following detailed description, including the appended claims, in . connection with the above-described drawings. Although the present invention is described in connection with exemplary embodiments, the present invention is not intended to be limited to the specific forms set forth herein. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
The present invention provides a system for Modbus communication in circuit breakers having wireless Sub-Giga frequency band. The system provides user convenience and freedom from wires. Additionally, the present invention provides advantage of using the sub-Giga hertz (sub 1 GHz) ISMfrequency band keeping power consumption low. The lower frequency signals give the added advantage of covering larger distance for

communication. The lower frequencies have more penetration capability through the metal walls of the switchboard panels.
Referring to figure 1, there is shown a system (100) for Modbus communication in circuit breakers. The system [100) includes electronic trip unit (10) capable of communicating wirelessly through Sub-Giga module (20). Specifically, the electronic trip unit (10) communicates with anyone of a switch board panel (30), and a graphical user interface (GUI)/panel display/PC-HMI (40) based control at remote location. Specifically, internal communication between the electronic trip unit (10) and the Sub-Giga Module (20) is achieved using Inter-Integrated Circuit, I2C.
Sub-Giga modules (20) include RF (Radio frequency) driver 1C, antenna and a power stabilizing circuit. The RF driver is connected to a microcontroller of the trip unit (10) by serial communication port along with handshaking signals. The microcontroller of the trip unit (10) has modbus stack implemented therein. Each trip unit (10) includes one Sub-Giga module (20) integrated therein. The Sub-Giga module (20) make their own network to communicate with other Sub-Giga modules and with master modules such as graphical user interface (GUI) or panel display (40). The PC-HMI/GUI/panel display (40) is configured to have Sub-Giga communication capability to communicate with the network. An auxiliary supply unit is an external DC supply given to the trip unit (10) and the Sub-Giga module (20).
In the system (100), the MODBUS communication is achieved wirelessly where the electronic trip unit (10) of the circuit Breaker communicates wirelessly with another electronic trip unit (not shown) or a compatible electronic circuitry in any other circuit breaker device (not shown). Using the system (100), a system engineer at a remote location can monitor the conditions at the electrical installation like metering of current, voltage,

temperature and the like and system protection settings. In case of an abnormal occurrence or fault/trip condition, the system engineer can log all the data for analysis using the system (100].
In an embodiment, the wireless communication using the system (100) is achieved within a distance of60 meters with concrete obstacles, 150 meters line-of-sight. However, it may be evident to those skilled in the art that the distance of wireless communication is easily increased by using RF Repeaters.
In the system (100), the wireless communication is achieved via IEEE 802.15.4 RF standard and the frequency of operation is 865 MHz to 867MHz.
Advantages of the invention
1. In system (100), the wireless Modbus communication in circuit breakers is achieved using the Sub-Giga frequency band, which results in significant reduction in power consumption.
2. The system (100) employs wireless communication which provides user convenience and freedom from wires.
3. The system (100) can be installed faster due to absence of wires.
4. The system (100) great advantage using the sub-Giga hertz license free ISM frequency band keeping power consumption low, wherein the lower frequency signals gives the added advantage of covering larger distance for communication. The lower frequencies have more penetration capability through the metal walls of the switchboard panels.

5. Using the system (100), the system's engineer has the convenience of monitoring, analyzing and/or taking the necessary corrective action from a remote location.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.

We Claim:
1. A system for Modbus communication in circuit breakers, the system comprising an electronic trip unit capable of communicating wirelessly through Sub-Giga module with anyone of a switch board panel and PC-HMI based control at remote location, wherein the internal communication between the electronic trip unit and the Sub-Giga Module is achieved using Inter-Integrated Circuit (I2C).
2. The system as claimed in claim 1, wherein the wireless communication between the electronic trip unit with anyone of the switch board panel and the PC-HMI based control is achieved within a distance of60 meters with concrete obstacles and 150 meters line-of-sight.