DESC:TECHNICAL FIELD

The present subject matter described herein, in general relates to circuit breaker and more particularly, to connecting circuit breakers directly on Ethernet to provide internet connectivity.

BACKGROUND

Circuit breakers are widely used to protect electrical lines and equipment. The circuit breaker monitors current through an electrical conductor and trips to interrupt the current if certain criteria are met. One such criterion is the maximum continuous current permitted in the protected circuit. The breaker can be used to protect circuits in which the maximum continuous current is less than the circuit breaker frame rating, in which case the circuit breaker is configured to trip if the current exceeds the maximum continuous current established for the particular circuit in which it is used. This is known as the circuit breaker current rating.

An electronic trip unit (“ETU”) is a device that is used in conjunction with an electromechanical circuit breaker to control the current verses time trip response. The time versus current trip characteristics are, in part, a function of the maximum continuous current permitted by the circuit breaker. For very large magnitude over currents, such as would be produced by a fault, the microcomputer is programmed to generate a trip signal instantaneously. The ETU may be connected to plurality of surrounding device using an Ethernet.

Ethernet is one of the most growing network connections to connect network devices providing industrial applications. A TCP/IP stack defines a set of protocols that allows network devices to connect to a specific device (ETU in this case) and exchange the data on a network. These protocols, defined by RFC (request for comments), enable an embedded device to send email, serve web pages, transfer files, and provide other basic connectivity functions. The web server is identified by its unique IP address of the devices and can be controlled remotely from anywhere in the world as long as the authorization is in order. In order to connect the devices in the network with the internet a circuit breaker is required.

For connecting circuit breaker over internet, it requires connection interface with web server that integrates field devices at control level. Circuit breaker generally requires limited data exchange on network.

So there exists a need to provide time and cost effective solution for connecting the various nodes/devices directly to the internet using circuit breaker without having need to couple with web server.

SUMMARY

This summary is provided to introduce concepts related to an electronic trip unit capable of internet connectivity. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.

In one implementation, the above discussed and other drawbacks and deficiencies are overcome or alleviated by the present system.

In one implementation the present invention provides an embedded web server based on the ultra low-power microcontroller. The solution provided in the present invention consists of both hardware and software. An Ethernet LAN controller offers the physical connection to the Internet with a downsized TCP/IP protocol stack.

In one implementation, the web server integrated trip unit for internet connectivity is disclosed.

In one implementation, the trip unit to connect circuit breaker directly on Ethernet and transmitting TCP/IP data through trip unit to the remote host is disclosed.

In one implementation, embedding the entire web server data and its stack into trip unit is disclosed. Hence, the need for server interface is removed and customer gets direct access to circuit breaker over internet.

In one implementation, a cost effective solution i.e., the trip unit, for connecting circuit breaker on internet without having need to couple with web server is disclosed.

In one implementation, the trip unit for incorporating the web server functions into trip unit, and thereby making connection simplicity and cost effective for remote access of data over Ethernet is disclosed.

In one implementation, the trip unit incorporating application data for STACK definition for Ethernet web server is disclosed.

In one implementation, the trip unit consisting of microcontroller consisting of MAC layer and PHY layer or transceiver consisting of these layers is disclosed.

In one implementation, the trip unit containing data for web page to be accessed by remote host is disclosed.

In one implementation, the trip unit having feature to specify network ID by the customer over which the device communicates on network is disclosed.

Accordingly, in one implementation, a system for implementing an embedded web server based on an ultra low-power microcontroller with at least six input/output ports configured to provide an interface to at least one Ethernet controller is disclosed. The system is configured to operate in at least three different modes comprising I/O space, memory space, and as a direct memory access (DMA) slave.

In one implementation, a system for implementing an embedded web server based on a ultra low-power microcontroller is disclosed. The system comprises an electronic trip unit (104) including the ultra low-power microcontroller (106) to monitor an operation of an electrical circuit, wherein the electronic trip unit works as embedded web server; a plurality of nodes (108) communicably coupled to the electronic trip unit (104), and configured to access the embedded web server; and a non-volatile memory (110), present in the electronic trip unit, configured to store at least one interface at least one Ethernet controller.

In one implementation, the present invention comprises two main components, microcontroller and the Ethernet controller. The microcontroller with 60KB of flash memory and 2KB of RAM may be used. This is used for storing and transferring web pages in addition to protection and metering function. It has also six general-purpose input/output ports that may be used for interfacing to the LAN controller. . The Ethernet controller bus interface is simple to interface with a microcontroller directly. General I/O port pins of the microcontroller are used to provide a bus interface to the LAN controller. The availability of this device in a 3-V version is another benefit for interfacing it with the microcontroller.

BRIEF DESCRIPTION OF THE ACCOMPNAYING DRAWINGS

The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.

Figure 1 illustrates a Serial communication network on field level, in accordance with an embodiment of the present subject matter.

Figure 2 illustrates internet connectivity through web server, in accordance with an embodiment of the present subject matter.

Figure 3 illustrates Internet connectivity directly through circuit breaker, in accordance with an embodiment of the present subject matter.

Figure 4 illustrates a communication between circuit breaker and remote host, in accordance with an embodiment of the present subject matter.

Figure 5 illustrates a web page for data access at remote host, in accordance with an embodiment of the present subject matter.

Figure 6 illustrates hardware block diagram, in accordance with an embodiment of the present subject matter.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Preferred embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail.

The terms and words used in the following description 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.

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

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.

In one implementation, a trip unit contains a code for a user application that does protection function, human machine interface and other general function required by circuit breaker is disclosed. In addition it has function to act as web server for internet connectivity.

The entire stack for Ethernet i.e. TCP/IP is written in the trip unit and the code for development of the web server with a range of applications on top of the TCP/IP stack. The trip unit provides internal flash memory for holding web interface site data which can be accessed by remote host. The trip unit runs at high frequency sufficient enough to handle the entire necessary incoming request and at the same time perform basic function of protection.

The layer of stack written in trip unit may follow the same layered structure as used in TCP/IP protocol suite. The IP address to Ethernet MAC addresses is configurable by customer based on network interface.

While aspects of a trip unit for connecting circuit breakers directly on Ethernet may be implemented in any number of different computing systems, environments, and/or configurations, the embodiments are described in the context of the following exemplary system.

Referring now to figure 1, a serial communication network on field level is shown, in accordance with an embodiment of the present subject matter.

In one embodiment, figure 1 shows a connection of the circuit breaker at a field level where each device is provided by identification (ID) for it to communicate to a network master. In one example, the network could be Modbus or profibus or any other serial communication network. The network has a plurality of nodes. The node is a device that is present in the network which is capable of communicating with the other devices or nodes available in the network. Examples of the node or devices may include, but are not limited to, a portable computer, a personal digital assistant, a handheld device, and a workstation, a computer, laptop, and the like those are available in the network. The nodes may communicate with each other using the data.

Referring now to figure 2, internet connectivity through web server is shown, in accordance with an embodiment of the present subject matter. In one embodiment, figure 2 shows a typical connection of control device or nodes to the field device using RS-485 gateway. These devices interface with network master which acts as the web server. The web server may further communicate with the devices that are available in the network over Ethernet. The Communication may be using the data and at least one web service.

Referring now to figure 3, internet connectivity directly through the circuit breaker (102) is shown, in accordance with an embodiment of the present subject matter. In one example, figure 3 shows a novelty of the invention. The web server functions are incorporated into the circuit breaker (102) (trip unit (104), so that it can directly communicate with the other devices (108) available in the network over Ethernet by simply configuring it with a device i8dentification (ID).

Referring now to figure 4, a communication between circuit breaker (102) and remote host (108) is shown, in accordance with an embodiment of the present subject matter. In one example, the figure 4 shows a handshaking between the circuit breaker and a remote host (the device) over internet. The remote host (108) enters the device ID. This request is sent to trip unit (104) which sends the web site data stored into the non-volatile memory (internal flash memory) (110). Now the host (108) could access the data of circuit breaker (102) based on its access level granted.

Accordingly, in one implementation, a system for implementing an embedded web server based on an ultra low-power microcontroller with at least six input/output ports configured to provide an interface to at least one Ethernet controller is disclosed. The system is configured to operate in at least three different modes comprising I/O space, memory space, and as a direct memory access (DMA) slave.

In one implementation, a system for implementing an embedded web server based on a ultra low-power microcontroller is disclosed. The system comprises an electronic trip unit (104) including the ultra low-power microcontroller (106) to monitor an operation of an electrical circuit, wherein the electronic trip unit works as embedded web server; a plurality of nodes (108) communicably coupled to the electronic trip unit (104), and configured to access the embedded web server; and a non-volatile memory (110), present in the electronic trip unit, configured to store at least one interface at least one Ethernet controller.
In one implementation, the interface is configured to be implemented using 14 electrical signals.

In one implementation, an isolation transformer configured to implement the interface.

In one implementation, the interface provides at least one parameter settings tab for changing at least one parameter associated with the electrical circuit.

In one implementation, the interface is configured to provide an internet connection for connecting the circuit breaker to World Wide Web.

In one implementation, the handshaking between the embedded web server in the electronic trip unit and the nodes is achieved by:
· entering node identification data;
· transmitting the node identification data to the electronic trip unit;
· displaying at least one parameter associated with the node, and
· accessing the parameters based on an access level rights granted to the nodes.

In one implementation, the node identification is validated based on the pre-stored data.

In one implementation, the parameters associated with the node are accessed remotely by using the interface.

Referring now to figure 5, a web page for data access at remote node (108) is shown, in accordance with an embodiment of the present subject matter. In one example, the parameter settings tab is made available to a user for the performing the communication as shown in figure 4.

Referring now to figure 6 illustrates hardware block diagram, in accordance with an embodiment of the present subject matter. In one implementation, the present invention comprises two main components, microcontroller and the Ethernet controller.. The microcontroller with 60KB of flash memory and 2KB of RAM may be used. This is used for storing and transferring web pages in addition to protection and metering function. It has also six general-purpose input/output ports that may be used for interfacing to the LAN controller.. The Ethernet controller bus interface is simple to interface with a microcontroller directly. General I/O port pins of the microcontroller are used to provide a bus interface to the LAN controller. The availability of this device in a 3-V version is another benefit for interfacing it with the microcontroller.

In one implementation, interfacing between the LAN Controller and the microcontroller unit (MCU) as per the present invention is efficiently achieved. The Ethernet controller can operate in three different modes: I/O space, memory space, and as a DMA slave. All of these modes have their advantages and disadvantages. The I/O space operation mode is the best choice for default mode. The most important fact is that it is possible to use an 8-bit width data bus. This data bus is connected to general I/O-port 5 of the microcontroller. The Ethernet controller in I/O mode is accessed through eight 16-bit I/O ports that are mapped into 16 registers. To access them, a 4-bit address bus width is used. There are also two control lines used, IOR and IOW. These signals are active-low and indicate whether there is a read or a write access in progress. The whole interface is implemented by using only 14 electrical signals. All unused pins of the CS8900A are driven to appropriate levels to choose the operating mode and configure the bus interface. For example, after any reset the Ethernet controller responds to default I/O address 0x300. The address lines that are not changed while accessing this I/O address are hardwired to 0x300. After applying a valid I/O address to the address bus and driving one of the control lines (IOR IOW) to low, data transfer over the data bus can take place.

In one implementation, connection to the network as per the present invention is efficiently achieved. The Ethernet controller includes an integrated 10Base-T transceiver. It may contain all the analog and digital circuitry needed for implementing the LAN interface by the use of a simple isolation transformer. Similar devices may substitute for this part, but attention must be paid to the voltage turn ratio between the primary and secondary windings. The resistor used to terminate the receive lines and the resistors in series with the transmit lines are used for impedance matching. The capacitors on the LAN side of the isolation transformer may be optionally populated if a shielded RJ45 connector is used. In this case, the signal GNDA must be connected to the case shield. A standard RJ45 patch cable can be used to connect the module to either a 10-Mbps or 100- Mbps hub. A 100-Mbps hub automatically switches down its transfer speed to 10 Mbps if it detects the CS8900A running at 10 Mbps.

In one implementation, as already known to the person skilled in that art, the main task of the Ethernet module is the encapsulation of functions for data transmission by the sub functions. The Ethernet module also generates the clock scheme used for accessing the internal registers of the Ethernet controller. The software protocols for transferring data over a TCP/IP connection are implemented. It uses functions of the Ethernet module to send and receive data and provides a simple, easy-to-use API to the upper application layer. In a TCP/IP stack one of the following events can occur:
· A frame is received over the LAN
· The application triggers an event (for example opens a connection, sends data, etc.)
· A time-out occurs
· An error occurs (network error, connection is reset by the opponent).

The software implements the essential parts of the standards. The most important function of this stack is Manage_Nw_Fn(). This function must be called periodically by the user application. The event handling of the TCP is done here. Different flags are polled in both the Ethernet controller and the MCU. According to the flags, this function branches to the appropriate event handler. The more often this function is called, the better the performance of the TCP is. A special set of event handlers is the user events. They are triggered by calling one of the stack functions directly by the application.

In one implementation, while implementing a TCP, different tasks are to be performed with controlled timing. In one example, the stack may use Timer_A of the microcontroller, which is configured by the function TCP LowLevelInit(). The protocol specification for TCP demands a 32-bit wide, free-running counter with a frequency of 250 kHz. It is used for getting the initial sequence number (ISN) needed for opening a connection. An 8-MHz crystal drives the microcontroller. This clock is divided by 32, down to 250 kHz, and sources a 16-bit wide, free-running counter. An interrupt is generated each time the register completes an interval (every 0.262s using an 8-MHz MCU clock). In this case, the interrupt service routine TCPClockManager() increments the 16-bit number ISNGenHigh. This variable represents the upper word of the ISN. On each timer interrupt event, the variable TCP Timer is also incremented. It is used to generate the timer events needed for a TCP. For example, if the other TCP does not acknowledge a segment sent within a specific time interval, a retransmission is triggered. Also, on closing a connection, the TCP has to wait before another TCP connection can be opened. This may not disturb the set scheduler of trip unit for protection and metering which uses separate timer and registers for fault processing.

In one example, the dynamic web page as per the present invention may provide a simple web page. It uses the process of refreshing dynamic strings. Along with general text, it shows the dynamic values.

Conventionally, during the compatibility of the stack in communicating with other TCPs, limitations of the protocol specifications may be listed as below:
· Only one TCP session is possible at a time
· No reassembling of fragmented incoming IP frames
· No buffering of TCP segments which are delivered out-of-order
· No checksum checking of incoming data
· No support for IP type-of-service (TOS) and security options
· Ignoring of any TCP options.

In the present invention, the compatibility is achieved by implementing only the important parts of the protocol specifications, but also is due to the tolerance of the other TCPs. Solution may need additional 4.2KB of flash EEPROM as program memory, 100 bytes of flash EEPROM as memory for storing constants, and about 700 bytes of RAM.

Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features:

One feature of the invention is that, the application data for STACK definition for Ethernet web server is incorporated in the trip unit.

Another feature of the invention is that, the trip unit comprises of the microcontroller consisting of MAC layer and PHY layer or transceiver consisting of these layers.

Yet another feature of the invention is that, the data for web page is directly accessed by the remote host using the trip unit.

Still another feature of the invention is that, the trip unit may specify network ID by the customer over which the device communicates on network.

Although the electronic trip unit capable of internet connectivity has been described in language specific to structural features and/or methods, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific features or methods or devices described. Rather, the specific features are disclosed as examples of implementations for an electronic trip unit capable of internet connectivity. Further, the known components/ elements/ working of such components may not be disclosed in the present invention to avoid the complexity of the invention; however the working may be understood by the person having ordinary skills in the art.
,CLAIMS:1. A system (100) CHARACTERIZED IN THAT for implementing an embedded web server based on an ultra low-power microcontroller with at least six input/output ports configured to provide an interface to at least one Ethernet controller; and configured to operate in at least three different modes comprising I/O space, memory space, and as a direct memory access (DMA) slave.

2. The system as claimed in claim 1, wherein the interface is configured to be implemented using 14 electrical signals.

3. The system as claimed in claim 1 comprises an isolation transformer configured to implement the interface.

4. A system (100) for implementing an embedded web server based on a ultra low-power microcontroller, the system comprising:
an electronic trip unit 104) including the ultra low-power microcontroller (106) to monitor an operation of an electrical circuit, wherein the electronic trip unit works as embedded web server;
a plurality of nodes (108) communicably coupled to the electronic trip unit (104), and configured to access the embedded web server; and
a non-volatile memory (110), present in the electronic trip unit, configured to store at least one interface at least one Ethernet controller.

5. The system (100) as claimed in claim 4, wherein the interface provides at least one parameter settings tab for changing at least one parameter associated with the electrical circuit.

6. The system (100) as claimed in claim 4, wherein the interface is configured to provide an internet connection for connecting the circuit breaker to World Wide Web.

7. The system (100) as claimed in claim 4, wherein the handshaking between the embedded web server in the electronic trip unit and the nodes is achieved by:
entering node identification data;
transmitting the node identification data to the electronic trip unit;
displaying at least one parameter associated with the node, and
accessing the parameters based on an access level rights granted to the nodes.

8. The system (100) as claimed in claim 7, wherein the node identification is validated based on the pre-stored data.

9. The system (100) as claimed in claim 7 and 8, wherein the parameters associated with the node are accessed remotely by using the interface.