Title of Invention	AN EMBEDDED PROTOCOL CONVERTER FOR INTERFACING ELECTRONIC CONTROLLERS OF ELECTROSTATIC PRECIPITATOR AND DISTRIBUTED CONTROL SYSTEM
Abstract	This invention relates to an embedded protocol converter for converting specific or dedicated protocol to general purpose MODBUS protocol the protocol converter providing communication interface between a plurality of field level controllers (20- 25) and a plant level controller (26) of an electrostatic precipitator, the field level controllers having different communication protocol, the protocol converter comprising a microprocessor (01) enabled for +/10mA current loop communication, RS485 communication and CAN bus communication, the hardware being supported by software structure stored in a flash memory of the microcontroller (01).

Title of Invention

AN EMBEDDED PROTOCOL CONVERTER FOR INTERFACING ELECTRONIC CONTROLLERS OF ELECTROSTATIC PRECIPITATOR AND DISTRIBUTED CONTROL SYSTEM

Abstract

This invention relates to an embedded protocol converter for converting specific or dedicated protocol to general purpose MODBUS protocol the protocol converter providing communication interface between a plurality of field level controllers (20- 25) and a plant level controller (26) of an electrostatic precipitator, the field level controllers having different communication protocol, the protocol converter comprising a microprocessor (01) enabled for +/10mA current loop communication, RS485 communication and CAN bus communication, the hardware being supported by software structure stored in a flash memory of the microcontroller (01).

Full Text	FIELD OF INVENTION This invention relates to a microcontroller based protocol converter for converting dedicated & proprietary protocol to standard MODBUS serial communication protocol. This protocol converter can be adapted for interfacing the electronics controllers of Electro Static Precipitator (ESP) with the Distributed Control System (DCS). BACKGROUND OF INVENTION Electrostatic precipitator is used for collecting fly ash from flue gas in a thermal power plant. This reduces pollution of the atmosphere. The ESP has its own dedicated electronic controllers BAPCON and RAPCON for controlling purposes and achieving optimum performance. The ESP controllers, BAPCON & RAPCON are microprocessor based controllers with communication facility. This communication is through a balanced current loop, with dedicated data format. The operating parameters of the ESP can be varied locally through BAPCON and RAPCON front-facia-keyboard and the parameters could be monitored from the front-facia-display. Further, the operating parameters of the ESP can also be locally controlled from a local field control panel. For this purpose, suitable manpower have to be positioned in the ESP control room, which entails high cost and human-error. Presently, to facilitate automated plant operation, the control of Electrostatic precipitator from a central location like the plant, a distributed control system (DCS) is often required. The Electrostatic precipitator data are required to be sent for control and monitoring to the DCS System. The ESP controllers like BAPCON / RAPCON use dedicated data format & proprietary protocol. So, to control BAPCON/ RAPCON from the plant DCS, it is necessary to share this dedicated data format & protocol with the DCS Systems. To protect the dedicated protocol format, it is required to convert the dedicated protocol to a general-purpose format like MODBUS over RS485 interface or CAN bus interface. Accordingly a need exists for providing a protocol converter for fast and easy communication between the controllers of electrostatic precipitator and the distributed control system. It is also very important to provide a general purpose communication format like MODBUS interface with the DCS systems. This converter protects the proprietary protocol to be shared with the third party DCS systems. Moreover, control and monitoring of only the critical parameters of ESP can presently be given to the DCS system. OBJECTS OF THE INVENTION It is therefore an object of the invention to propose a microcontroller based protocol converter for converting dedicated and proprietary protocol to standard MODBUS-Serial communication protocol which eliminates the disadvantages of prior art. Another object of the invention is to propose a microcontroller based protocol converter for converting dedicated and proprietary protocol to standard MODBUS-Serial communication protocol which enables automatic control and monitoring of the ESP operating parameters from a centrally located Distributed Control System (DCS). A further object of the invention is to propose a microcontroller based protocol converter for converting dedicated and proprietary protocol to standard MODBUS-Serial communication protocol which impart economy in the operation of the ESP owing to elimination of skilled personnel for the control and monitoring of plant control. SUMMARY OF THE INVENTION Accordingly, there is provided an embedded protocol converter using microcontroller to convert the specific or dedicated protocol to general purpose MODBUS protocol, the protocol converter providing communication interface between a plurality of field level controllers and a plant level controller of an electrostatic precipitator, the field level controllers having different communication protocol, the protocol converter comprising a hardware block for +/10mA current loop communication, RS-485 communication and CAN bus communication. The hardware block is supported by software structure stored in a flash memory of the microcontroller. Thus, the protocol converter of the invention acts as a translator between the ESP controllers and the DCS. The necessity of the protocol converter arises from the fact that the protocol used by the electronic controllers of ESP is of proprietary nature, and it has to be interfaced with a DCS System. The protocol required by the majority of the DCS is serial communication in MODBUS format protocol. The MODBUS protocol is a universally accepted standard protocol for serial communication. Further the hardware used for serial communication by electronic controllers of the ESP is current loop communication, whereas the hardware required by the DCS for serial communication is RS485 serial communication. This protocol converter acting as a translator between the ESP electronic controllers and the DCS, bridges both the hardware and software gaps as explained below: The protocol converter overcomes the software gap by converting the proprietary protocol serial communication format into MODBUS protocol serial communication format. The hardware gap is overcome by converting the current loop communication into RS485 serial communication. Since this hardware is designed to meet general industrial requirements like RS232 to RS485 conversion and reading digital inputs/outputs and analog inputs, this can be used for other general application also. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig. 1 is hardware block diagram of the protocol converter according to the invention. Fig. 2 is software logic diagram of the protocol converter of Fig -1. Fig. 3 is an Interface diagram of the protocol converter with specific protocol based field level controllers and the plant level controller of the ESP Fig. 4 is Typical Interface diagram of the protocol converter with specific protocol based field level controllers and plant level controller of ESP DETAILED DESCRIPTION OF THE INVENTION The hardware block diagram of the protocol converter (08) for communication protocol conversion of electrostatic precipitator is shown in Fig.l. In the embedded hardware block diagram (a), a block (01) acts as the microcontroller. Hardware for three types of communication is shown in three blocks (02), (03) and (04). The block (02) has the circuit for +/-10mA current loop communication. This circuit interfaces the specific protocol based field level controllers through a first port (05). The processor (01) receives data frame through the blocks (02 and the port 05) and reformat in accordance with the protocol to be transmitted. The processor (01) has a flash memory to store the software. The block (03) has the hardware circuit for CAN communication. CAN protocol based field level controllers are connected through a port (06) and a transceiver circuit (03). The processor (01) converts the CAN frame into required protocol format. The block (04) has the hardware circuit for RS-485 communication. MODBUS protocol based plant level controller is connected through a port (07) and a transceiver circuit (04). The processor (01) converts the MODBUS frame into required protocol format. Fig.2 shows the software logic diagram of the present invention. Software logic is shown in block (09). It consists of a main block (10), a plurality of communication driver blocks (12), (14) and (16), and a corresponding number of communication protocol conversion blocks (11), (13), (15) and (17). The main block (10) initiates default values and various tasks to be performed during the operation. The communication driver block (12) receives and transmits specific protocol based message/data frames, the block (14) receives and transmits CAN protocol based data frames and the, and the block (16) receives and transmits MODBUS protocol based communication frames The communication protocol conversion block (11) is enabled to convert specific protocol based messages into MODBUS protocol based messages. The communication protocol conversion block (13) enables conversion from CAN protocol based messages into MODBUS protocol based messages. The communication protocol conversion block (15) is configured to convert MODBUS protocol based messages into specific protocol based messages. The communication protocol conversion block (17) has software for converting MODBUS protocol based messages into CAN protocol based messages. Software for the communication blocks (12,14,16) and the protocol conversion blocks (11,13,15,19) are stored in the flash memory of the processor (01). Configuration software is made for selecting the required protocol conversion. Fig 3 shows the interface diagram of the protocol converter (08) with specific protocol based field level controllers (20 to 25) and MODBUS protocol based plant level controller (26). Specific communication protocol based field level controllers (20), (21), (22), (23), (24) and (25) are connected through a +/10mA current loop communication (19). The field level controllers (20 - 25) are interfaced to a plant level controller (26) using the protocol converting device (08) through a RS-485 communication bus (26). Fig 4 shows a typical interface diagram of the protocol converter (08) with the plant level controllers and the field level controllers of the electrostatic precipitator. WE CLAIM 1. An embedded protocol converter for converting specific or dedicated protocol to general purpose MODBUS protocol the protocol converter providing communication interface between a plurality of field level controllers (20-25) and a plant level controller (26) of an electrostatic precipitator, the field level controllers having different communication protocol, the protocol converter comprising a microprocessor (01) enabled for +/10mA current loop communication, RS-485 communication and CAN bus communication, the hardware being supported by software structure stored in a flash memory of the microcontroller (01). 2. The embedded protocol converter as claimed in claim 1, wherein the hardware structure comprises at least three blocks (02, 03, 04). 3. The embedded protocol converter as claimed in claim 1, wherein the first block (02) of said at least three blocks, comprises a circuit for +/- 10mA current loop communication which interfaces the specific protocol based field level controllers (20-25) through a first port (05). 4. The embedded protocol converter as claimed in claims 1 to 3, wherein the second block (03) comprises a hardware circuit for CAN -communication to which the CAN -based field level controllers are connected via a second port (06). 5. The embedded protocol converter as claimed in claims 1 to 4, wherein the third block (04) comprises a hardware circuit for RS485 communication to which the MODBUS-based field controllers are connected via a third port (07). 6. The embedded protocol converter as claimed in claim 1, wherein the software support structure (09) comprises a main block (10), a plurality of communication driver blocks (12, 14, 15), and a corresponding number of communication protocol conversion blocks (11,13,15,17). ABSTRACT AN EMBEDDED PROTOCOL CONVERTER FOR INTERFACING ELECTRONIC CONTROLLERS OF ELECTROSTATIC PRECIPITATOR AND DISTRIBUTED CONTROL SYSTEM This invention relates to an embedded protocol converter for converting specific or dedicated protocol to general purpose MODBUS protocol the protocol converter providing communication interface between a plurality of field level controllers (20- 25) and a plant level controller (26) of an electrostatic precipitator, the field level controllers having different communication protocol, the protocol converter comprising a microprocessor (01) enabled for +/10mA current loop communication, RS485 communication and CAN bus communication, the hardware being supported by software structure stored in a flash memory of the microcontroller (01).

Full Text

FIELD OF INVENTION
This invention relates to a microcontroller based protocol converter for
converting dedicated & proprietary protocol to standard MODBUS serial
communication protocol. This protocol converter can be adapted for interfacing
the electronics controllers of Electro Static Precipitator (ESP) with the Distributed
Control System (DCS).
BACKGROUND OF INVENTION
Electrostatic precipitator is used for collecting fly ash from flue gas in a thermal
power plant. This reduces pollution of the atmosphere. The ESP has its own
dedicated electronic controllers BAPCON and RAPCON for controlling purposes
and achieving optimum performance. The ESP controllers, BAPCON & RAPCON
are microprocessor based controllers with communication facility. This
communication is through a balanced current loop, with dedicated data format.
The operating parameters of the ESP can be varied locally through BAPCON and
RAPCON front-facia-keyboard and the parameters could be monitored from the
front-facia-display. Further, the operating parameters of the ESP can also be
locally controlled from a local field control panel. For this purpose, suitable
manpower have to be positioned in the ESP control room, which entails high cost
and human-error.

Presently, to facilitate automated plant operation, the control of Electrostatic
precipitator from a central location like the plant, a distributed control system
(DCS) is often required. The Electrostatic precipitator data are required to be
sent for control and monitoring to the DCS System. The ESP controllers like
BAPCON / RAPCON use dedicated data format & proprietary protocol. So, to
control BAPCON/ RAPCON from the plant DCS, it is necessary to share this
dedicated data format & protocol with the DCS Systems. To protect the
dedicated protocol format, it is required to convert the dedicated protocol to a
general-purpose format like MODBUS over RS485 interface or CAN bus interface.
Accordingly a need exists for providing a protocol converter for fast and easy
communication between the controllers of electrostatic precipitator and the
distributed control system.
It is also very important to provide a general purpose communication format like
MODBUS interface with the DCS systems. This converter protects the proprietary
protocol to be shared with the third party DCS systems. Moreover, control and
monitoring of only the critical parameters of ESP can presently be given to the
DCS system.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a microcontroller based
protocol converter for converting dedicated and proprietary protocol to standard
MODBUS-Serial communication protocol which eliminates the disadvantages of
prior art.

Another object of the invention is to propose a microcontroller based protocol
converter for converting dedicated and proprietary protocol to standard
MODBUS-Serial communication protocol which enables automatic control and
monitoring of the ESP operating parameters from a centrally located Distributed
Control System (DCS).
A further object of the invention is to propose a microcontroller based protocol
converter for converting dedicated and proprietary protocol to standard
MODBUS-Serial communication protocol which impart economy in the operation
of the ESP owing to elimination of skilled personnel for the control and
monitoring of plant control.
SUMMARY OF THE INVENTION
Accordingly, there is provided an embedded protocol converter using
microcontroller to convert the specific or dedicated protocol to general purpose
MODBUS protocol, the protocol converter providing communication interface
between a plurality of field level controllers and a plant level controller of an
electrostatic precipitator, the field level controllers having different
communication protocol, the protocol converter comprising a hardware block for
+/10mA current loop communication, RS-485 communication and CAN bus
communication. The hardware block is supported by software structure stored in
a flash memory of the microcontroller.

Thus, the protocol converter of the invention acts as a translator between the
ESP controllers and the DCS. The necessity of the protocol converter arises from
the fact that the protocol used by the electronic controllers of ESP is of
proprietary nature, and it has to be interfaced with a DCS System. The protocol
required by the majority of the DCS is serial communication in MODBUS format
protocol. The MODBUS protocol is a universally accepted standard protocol for
serial communication. Further the hardware used for serial communication by
electronic controllers of the ESP is current loop communication, whereas the
hardware required by the DCS for serial communication is RS485 serial
communication.
This protocol converter acting as a translator between the ESP electronic
controllers and the DCS, bridges both the hardware and software gaps as
explained below:
The protocol converter overcomes the software gap by converting the
proprietary protocol serial communication format into MODBUS protocol serial
communication format. The hardware gap is overcome by converting the
current loop communication into RS485 serial communication.
Since this hardware is designed to meet general industrial requirements like
RS232 to RS485 conversion and reading digital inputs/outputs and analog inputs,
this can be used for other general application also.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 is hardware block diagram of the protocol converter according to the
invention.
Fig. 2 is software logic diagram of the protocol converter of Fig -1.
Fig. 3 is an Interface diagram of the protocol converter with specific protocol
based field level controllers and the plant level controller of the ESP
Fig. 4 is Typical Interface diagram of the protocol converter with specific protocol
based field level controllers and plant level controller of ESP
DETAILED DESCRIPTION OF THE INVENTION
The hardware block diagram of the protocol converter (08) for communication
protocol conversion of electrostatic precipitator is shown in Fig.l.
In the embedded hardware block diagram (a), a block (01) acts as the
microcontroller. Hardware for three types of communication is shown in three
blocks (02), (03) and (04). The block (02) has the circuit for +/-10mA current
loop communication. This circuit interfaces the specific protocol based field level
controllers through a first port (05). The processor (01) receives data frame
through the blocks (02 and the port 05) and reformat in accordance with the
protocol to be transmitted. The processor (01) has a flash memory to store the
software.

The block (03) has the hardware circuit for CAN communication. CAN protocol
based field level controllers are connected through a port (06) and a transceiver
circuit (03). The processor (01) converts the CAN frame into required protocol
format.
The block (04) has the hardware circuit for RS-485 communication. MODBUS
protocol based plant level controller is connected through a port (07) and a
transceiver circuit (04). The processor (01) converts the MODBUS frame into
required protocol format.
Fig.2 shows the software logic diagram of the present invention.
Software logic is shown in block (09). It consists of a main block (10), a plurality
of communication driver blocks (12), (14) and (16), and a corresponding number
of communication protocol conversion blocks (11), (13), (15) and (17).
The main block (10) initiates default values and various tasks to be performed
during the operation.
The communication driver block (12) receives and transmits specific protocol
based message/data frames, the block (14) receives and transmits CAN protocol
based data frames and the, and the block (16) receives and transmits MODBUS
protocol based communication frames
The communication protocol conversion block (11) is enabled to convert specific
protocol based messages into MODBUS protocol based messages.

The communication protocol conversion block (13) enables conversion from CAN
protocol based messages into MODBUS protocol based messages.
The communication protocol conversion block (15) is configured to convert
MODBUS protocol based messages into specific protocol based messages.
The communication protocol conversion block (17) has software for converting
MODBUS protocol based messages into CAN protocol based messages.
Software for the communication blocks (12,14,16) and the protocol conversion
blocks (11,13,15,19) are stored in the flash memory of the processor (01).
Configuration software is made for selecting the required protocol conversion.
Fig 3 shows the interface diagram of the protocol converter (08) with specific
protocol based field level controllers (20 to 25) and MODBUS protocol based
plant level controller (26).
Specific communication protocol based field level controllers (20), (21), (22),
(23), (24) and (25) are connected through a +/10mA current loop
communication (19). The field level controllers (20 - 25) are interfaced to a plant
level controller (26) using the protocol converting device (08) through a RS-485
communication bus (26).
Fig 4 shows a typical interface diagram of the protocol converter (08) with the
plant level controllers and the field level controllers of the electrostatic
precipitator.

WE CLAIM
1. An embedded protocol converter for converting specific or dedicated
protocol to general purpose MODBUS protocol the protocol converter
providing communication interface between a plurality of field level
controllers (20-25) and a plant level controller (26) of an electrostatic
precipitator, the field level controllers having different communication
protocol, the protocol converter comprising a microprocessor (01) enabled
for +/10mA current loop communication, RS-485 communication and CAN
bus communication, the hardware being supported by software structure
stored in a flash memory of the microcontroller (01).
2. The embedded protocol converter as claimed in claim 1, wherein the
hardware structure comprises at least three blocks (02, 03, 04).
3. The embedded protocol converter as claimed in claim 1, wherein the first
block (02) of said at least three blocks, comprises a circuit for +/- 10mA
current loop communication which interfaces the specific protocol based
field level controllers (20-25) through a first port (05).
4. The embedded protocol converter as claimed in claims 1 to 3, wherein the
second block (03) comprises a hardware circuit for CAN -communication
to which the CAN -based field level controllers are connected via a second
port (06).

5. The embedded protocol converter as claimed in claims 1 to 4, wherein the
third block (04) comprises a hardware circuit for RS485 communication to
which the MODBUS-based field controllers are connected via a third port (07).
6. The embedded protocol converter as claimed in claim 1, wherein the software
support structure (09) comprises a main block (10), a plurality of
communication driver blocks (12, 14, 15), and a corresponding number of
communication protocol conversion blocks (11,13,15,17).

ABSTRACT

AN EMBEDDED PROTOCOL CONVERTER FOR INTERFACING ELECTRONIC
CONTROLLERS OF ELECTROSTATIC PRECIPITATOR AND DISTRIBUTED
CONTROL SYSTEM
This invention relates to an embedded protocol converter for converting specific or
dedicated protocol to general purpose MODBUS protocol the protocol converter
providing communication interface between a plurality of field level controllers (20-
25) and a plant level controller (26) of an electrostatic precipitator, the field level
controllers having different communication protocol, the protocol converter
comprising a microprocessor (01) enabled for +/10mA current loop communication,
RS485 communication and CAN bus communication, the hardware being supported
by software structure stored in a flash memory of the microcontroller (01).

Documents:

00111-kol-2008-abstract.pdf

00111-kol-2008-claims.pdf

00111-kol-2008-correspondence others.pdf

00111-kol-2008-description complete.pdf

00111-kol-2008-drawings.pdf

00111-kol-2008-form 1.pdf

00111-kol-2008-form 2.pdf

00111-kol-2008-form 3.pdf

00111-kol-2008-gpa.pdf

111 kol 2008 final search report.pdf

111-KOL-2008-(12-03-2013)-ABSTRACT.pdf

111-KOL-2008-(12-03-2013)-AMANDED PAGES OF SPECIFICATION.pdf

111-KOL-2008-(12-03-2013)-CLAIMS.pdf

111-KOL-2008-(12-03-2013)-EXAMINATION REPORT REPLY RECEIVED.pdf

111-KOL-2008-(12-03-2013)-FORM-1.pdf

111-KOL-2008-(12-03-2013)-FORM-2.pdf

111-KOL-2008-(12-03-2013)-OTHERS.pdf

111-KOL-2008-(12-03-2013)-PA.pdf

111-KOL-2008-CORRESPONDENCE.pdf

111-KOL-2008-EXAMINATION REPORT.pdf

111-kol-2008-form 18.pdf

111-KOL-2008-GRANTED-ABSTRACT.pdf

111-KOL-2008-GRANTED-CLAIMS.pdf

111-KOL-2008-GRANTED-DESCRIPTION (COMPLETE).pdf

111-KOL-2008-GRANTED-DRAWINGS.pdf

111-KOL-2008-GRANTED-FORM 1.pdf

111-KOL-2008-GRANTED-FORM 2.pdf

111-KOL-2008-GRANTED-FORM 3.pdf

111-KOL-2008-GRANTED-SPECIFICATION-COMPLETE.pdf

abstract-00111-kol-2008.jpg

« Previous Patent

Next Patent »

Patent Number

257648

Indian Patent Application Number

111/KOL/2008

PG Journal Number

43/2013

Publication Date

25-Oct-2013

Grant Date

23-Oct-2013

Date of Filing

16-Jan-2008

Name of Patentee

BHARAT HEAVY ELECTRICALS LIMITED

Applicant Address

REGIONAL OPERATIONS DIVISION (ROD), PLOT NO : 9/1, DJBLOCK, 3RD FLOOR, KARUNAMOYEE, SALT LAKE CITY, WEST BENGAL KOLKATA-700091 BHEL HOUSE, SIRI FORT, NEW DELHI - 110049

Inventors:

#	Inventor's Name	Inventor's Address
1	ARUMUGAM MARIMUTHU	BOILER AUXILIARIES PLANT, BHEL, RANIPET-632 406
2	MUNIYANDI SHANTHI VASANTHA RANI	BOILER AUXILIARIES PLANT, BHEL, RANIPET-632 406

PCT International Classification Number

G08C15/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA