DESC:TECHNICAL FIELD

[001] The present subject matter described herein, in general, relates to a communication system and more particularly to communication system of a circuit breaker with a trip unit (electronic/thermal) and its supplementary modules using multiple communication protocols.

BACKGROUND

[002] Protection relays or electronic trip units are devices that have a function of measuring amounts of voltage, current, and power of an electric power distribution line and a function of detecting a fault state of a protection target, in addition to a basic relay function. Among such protection relays, a protection relay having a remote communication function is connected to a supervisory monitor through a communication line, and periodically transmits information (in other words data) of the protection relay to the supervisory monitor according to an industrial communication protocol.

[003] A Controller Area Network (CAN) is one of the industrial communication protocolsthat used for communication of information to and/or from an electronic trip unit or protection relay device and other substation units and/or the supervisory monitor unit. The CAN communication protocol is an effective support for distributed control or real-time control of serial communication network, the main application of data communication in the vehicle monitoring, switching control, manufacturing and other fields.CAN bus as the world's most widely used one field bus, industrial control fields has been widely used, andis considered the most promising of the field bus.

[004] The CAN communication protocol is based on the “broadcast communication mechanism”, which is based on a message-oriented transmission protocol. It defines message contents rather than stations and station addresses. Every message has a message identifier, which is unique within the whole network since it defines content and also the priority of the message. This is important when several stations compete for bus access (bus arbitration). As a result of the content-oriented addressing scheme a high degree of system and configuration flexibility is achieved. It is easy to add stations to an existing CAN network without making any hardware or software modifications to the present stations as long as the new stations are purely receivers. This allows for a modular concept and also permits the reception of multiple data and the synchronization of distributed processes. Also, data transmission is not based on the availability of specific types of stations, which allows simple servicing and upgrading of the network.

[005] Conventionally, the communication system as illustrated in figure 1 includes a host Communication Module (COM-module) acts as an interface between the circuit breaker and an external human machine interface (HMI). The host COM-module works on MODBUS protocol to provide monitoring, parameterization and control functions to the circuit breaker. MODBUS Protocol is a messaging structure used to establish master-slave/client-server communication between intelligent devices. It is a de facto standard, truly open and the most widely used network protocol in the industrial manufacturing environment. MODBUS is used in multiple master-slave applications to monitor and program devices; to communicate between intelligent devices and sensors and instruments; to monitor field devices or substation units using personal computers (PCs) and HMIs. However, in case of communication of different supplementary modules or substation units or field devices of different communication protocol, different host COM-modules was needed to be employed in the communication network working on different communication protocol and forming a new bus network with the same.

[006] The prior art document, US 6,839,790 discloses an interface device that includes a re-configurable circuit which provides access to a selected field-bus network from among several optional field-bus networks. However, the technique reported in the prior art generally require a user to have a prior knowledge of the particular type of field-bus to which he or she is connecting. Thus, if a user wants to connect to a Profibus network, the user must make that selection known, and then the interface will reconfigure itself. However, if the user does not know what type of process communication protocol is being used, or if the user's selection is erroneous, the interface may begin communicating using a protocol that is not compatible with the actual protocol in use. This may introduce dangerous signaling levels that may damage, or otherwisedegrade communication on the process control loop; damage or otherwise degrade the interface module itself, or potentially interfere with the proper operation of the process control loop.

[007] The prior art document, US 7,778,262 B2 discloses a method, apparatus, and system for communication between electronic devices using different protocols and different modulation schemes. More particularly the present invention related to a Radio frequency multiple protocol bridge. The illustrative apparatus which interfaces between electrical devices is provided with a plurality of modules configured to functionally execute one or more of the following steps: implementing the communication protocol(s) of one or more electronic devices, scanning for a first signal containing information transmitted in a learned communication protocol from one or more of the electrical devices, receiving and recognizing the first signal, decoding the first signal using the appropriate communication protocol to extract the desired information, translating the information extracted from the signal into a predetermined language, creating a second signal containing the translated information using a second communication protocol, sending the second signal to another electrical device, and receiving an acknowledgment that the second signal was received by the other electrical device.

[008] Thus, in view the hitherto drawbacks of the existing systems and mechanism for communication between electronic devices, there exists a dire need to provide an improved system for interfacing different communication protocol in a common communication network that is more reliable, accurate and cost-effective.

SUMMARY OF THE INVENTION

[009] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention below.

[0010] The mainobject of the present invention is to provide an improved communication system by using additional COM-module in a communication network for interfacing of different communication protocol using a common communication interface.

[0011] Another object of the present invention is to provide a mechanism for interfacing different communication protocols using a reliable, accurate and cost-effective method to manufacture, install and maintain.

[0012] Yet another object of the present invention is to provide a high speed communication solution.

[0013] In one implementation, the present invention provides an improved communication system with at least one additional COM module, a host COM-module and at least one supplementary module wherein the supplementary module is configured to communicate with the host-module and the additional COM module is configured to communicate with the host module. The Host COM-module forms a network bus with the trip unit and rest of the supplementary modules using a message based CAN protocol.

[0014] In one implementation,the present invention provides a means for interfacing diverse communication protocols like Profibus, Zigbee, Devicenet and the like.

[0015] In one implementation, the present invention provides an improved communication system with the interfacing of at least one additional or add-on independent module or card of at least one communication protocol selected from a group of Profibus, Zigbee, Devicenet and the like, with the existing host COM-module. These add-on modules communicate with the host COM-module using a CAN bus or serial peripheral interface (SPI).

[0016] In one implementation, the present invention provides an improved communication wherein the electronic trip unit and other supplementary modules communicate with the host COM-module on a CAN bus (Controlled Area Network bus). The host module communicates with the external world using a human machine interface (HMI) by means of a MODBUS protocol.

[0017] Accordingly, in one implementation, a communication system in a communication network to enable a communication between at least one circuit breaker and at least one external human machine interface (HMI) for interfacing of different communication protocol is disclosed. The communication system comprises a host module communicably coupled with at least one add-on module and at least one supplementary module, wherein theadd-on module is configured to convert at least one protocol to an external HMI understandable protocol; and the add-on module comprises a memory map data pre-stored to enable the communication between the circuit breaker and the external HMI via., the host module.

[0018] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

[0019] Figure 1 illustratesan existing communication system.

[0020] Figure 2 illustrates an improved communication system with additional COM-module, in accordance with an embodiment of the present subject matter.

[0021] Figure 3 illustrates a system of adding a different COM module to the communication system,in accordance with an embodiment of the present subject matter.

[0022] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0023] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

[0024] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

[0025] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

[0026] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0027] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0028] Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

[0029] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0030] Referring now to figure 1,a conventional communication system is illustrated. In one implementation, the conventional communication system includesan electronic trip unit, relay modules, host COM-module, which are in communication with each other using a common interface such as CAN bus.

[0031] Referring now to figure 2, addition of different COM modules to the communication system is illustrated.

[0032] Referring now to figure 3, an improved communication system by adding an additional COM module in the communication network is illustrated. In one implementation, the additional COM module maycommunicate with host COM module by means of CAN bus or SPI.

[0033] In one implementation, the host COM-module provides an interface between the circuit breaker and an external human interface (HMI). The host COM-module works on MODBUS protocol to provide monitoring, parameterization and control functions of the circuit breaker.

Working of the Host Com Module:

[0034] It is known to the person skilled in that art that, the electronic trip unit (ETU) of the circuit breaker works on a RS485 protocol, whereas the human machine interface such as PC or PLC understands RS232 protocol. To enable communication between the ETU and the PC, the host COM module of the present invention converts the RS485 protocol to a HMI understandable RS232 protocol.

[0035] Further, the host COM module of the present invention includes a built-in Modbus memory map customized for the said ETU. So the HMI easily understands the data sent by ETU with a simple configuration.

[0036] In one implementation, the data needed by the HMI is polled/ queried using a defined memory location in the ETU and sent on RS232 level signals. The said COM module understands this encrypted data and sends a request to the ETU on RS485 level signals which is understood by the ETU. The ETU in return sends the response to the host COM. It converts this data in RS232 level signals and sends to the HMI

[0037] In one implementation, the operation/parameters of circuit breaker such as but not limited to metering parameters like current, voltage, energy, power etc. may be monitored using the present invention.

[0038] In one implementation, the operation/parameters of circuit breaker such as but not limited to settings of the ETU for monitoring and protection i.e., parameterization may be achieved using the present invention.

[0039] In one implementation, the operation/parameters of circuit breaker such as but not limited to Command to turn the breaker ON/OFF/ TRIP remotely through HMI may be controlled by the present invention.

[0040] In one implementation, the host COM-module forms a network bus with the electronic trip unit and rest of the supplementary modules using a message based CAN protocol.

[0041] In one implementation, instead of having different host COM-modules working on the above different protocols and forming a new bus network with the same. The present invention provides technical advancement over the prior-art by providing an interfacing of add-on independent modules/cards of the Profibus, Zigbee, Devicenet, and the like protocols with the existing host COM-module. These add-on modules may communicate with the host COM-module using any existing proven technology like CAN bus or SPI.

[0042] In one implementation, the host COM module includes an additional interface to include further protocols to the same network. For example, if a network is made with existing COM module and other accessories of the ETU, and there is a need to introduce another COM module having a different protocol like Profibus, Zigbee, Devicenet etc. It may not at all necessary to disturb the existing configuration and connection. The new COM module with any protocol can be directly connected to the host COM module which is working on Modbus protocol. This is done using a connector as a hardware interface and CAN/SPI as a software interface. All the data from the system can be made available to external HMI in any protocol that is needed without actually disturbing the existing system.

[0043] Some of the important features of the present invention, considered to be noteworthy are mentioned below:
1. The present invention provides a high speed communication solution.
2. The present invention is a means of easy interface with simple connections
3. The present invention reduces power consumption by using existing power supplies
4. The add-on module will share majority of the hardware of the host COM-module thus making it a cost effective solution.
5. The present invention also aids in up-gradation of existing communication system with a fixed protocol to a user selectable protocol with great ease and less down-time.
,CLAIMS:1. A communication system in a communication network to enable a communication between at least one circuit breaker and at least one external human machine interface (HMI) for interfacing of different communication protocol, the communication system comprising:
a host module communicably coupled with at least one add-on module and at least one supplementary module, wherein
the add-on module is configured to convert at least one protocol to an external HMI understandable protocol; and
the add-on module comprises a memory map data pre-stored to enable the communication between the circuit breaker and the external HMI via., the host module.

2. The communication system as claimed in claim 1, wherein to enable communication,the data is polled/ queried, using the memory map data pre-stored,froman electronic trip unit (ETU) of the circuit breaker.

3. The communication system as claimed in claim 1, wherein the add-on module is coupled to the host module using a connector as a hardware interface and CAN/SPI as a software interface.

4. The communication system as claimed in claim 1, wherein the host module is configured to form at least one network bus with an electronic trip unit (ETU) and the supplementary modules using a message based on a CAN protocol.

5. The communication system as claimed in claim 1, wherein the add-on module is configured to communicate with the host module using a CAN bus or serial peripheral interface (SPI).

6. The communication system as claimed in claim 1, wherein the host module is configured to communicate with at least one user using a human machine interface (HMI) by means of a MODBUS protocol.