Title of Invention	"AN IMPROVED DEVICE FOR INTERFACING RS232C WITH TTY PORT."
Abstract	A system for conversion of data communication protocol from TTY (TELETYPE)-to RS 232C. which is capable of withstanding high ambient temperature, dust and voltage fluctuation, the system comprising: a plurality of transistors: means for isolation of input and out put: one or more single layered printed circuit board: and means to indicate power and communication failure. The system of the present invention provides directly 23v AC (which is available at site) to the converter so that use of an external power supply of 9v DC can be avoided. It further provides indication to show the on going data transmission between the PC based programming unit and PLC.

Title of Invention

"AN IMPROVED DEVICE FOR INTERFACING RS232C WITH TTY PORT."

Abstract

A system for conversion of data communication protocol from TTY (TELETYPE)-to RS 232C. which is capable of withstanding high ambient temperature, dust and voltage fluctuation, the system comprising: a plurality of transistors: means for isolation of input and out put: one or more single layered printed circuit board: and means to indicate power and communication failure. The system of the present invention provides directly 23v AC (which is available at site) to the converter so that use of an external power supply of 9v DC can be avoided. It further provides indication to show the on going data transmission between the PC based programming unit and PLC.

Full Text	Field of Invention The present invention relates to a system of conversion of data communication protocol from TTY (TELETYPE) to RS 232C. More particularly the present invention relates to a robust converter which is transistor based, single layered and opto isolated and thus adapted ic withstand high ambient temperature, dusty atmosphere and voltage fluctuation. The system also avoids the use of separate external power supply. Background and prior art RS232C is the most common data communication protocol in use today, as it is the most successful interface standard implemented today. Most of the programmable logic controller or intelligent sensors have TTY interface for programming device and operator panel. In a manufacturing plant, different types of programmable controller (PLC) and intelligent sensors are used for achieving automation. In the early days, only dedicated type of programming units was available, in which monopoly of the supplier existed, Without a programming unit, a user cannot interact with the PLC. Not only this, a user cannot see the application program. Demand for PC (Personal Computer) based programming unit has grown and users opted for PC based programming unit. However most of the reputed manufacturer of PLC has TTY interface in their central processing unit through which an operator or a user can interact with the PLC. In the PC side, 9 pin, RS-232C is the most common data communication protocol being used, as it is the most successful interface standard implemented today. Hence, the necessity of converting this TTY to RS-232C became a must. The conventional converter for converting this TTY to RS-232C, which is available in the market has many drawbacks. Such converter is designed using integrated circuit type IC 232CP 2 and requires an external DC power supply of 9v, which is not able to withstand the dusty atmosphere, high temperature and voltage fluctuation. IC based systems available in the market can withstand temperature only up to 45C. Moreover the conventional system consists of a single IC 232CP. a multilayered Printed circuit Board (PCB), which is very small in size. Being multilayered and small it is more prone to dust as dust cannot be easily removed. Also , being multilayered and small . it is very difficult to repair in case of failure. Further the conventional converter based on IC 232CP is expensive. The converter presently available is directly connected to field. Hence the CPU is prone to damage every six months or so. Further with the conventional converter there is no regulation of voltage fluctuations since the system is direct feed to the converter. In addition the conventional system does not have any indicator for power failure or communication failure. In view of the above short comings there is a need for converter which can withstand high ambient temperature and dust, is cost effective, can be easily cleaned, does not need separate power supply and is provided with adequate indicators for power failure and communication failure. The inventors have now found a system that uses transistors instead of integrated circuit; is single layered instead of multilayered and is optoisolated to protect CPU and thus the system of the present invention can overcome the above problems associated with the conventional systems. Further being provided with internal conversion no separate power supply ie no adaptor is required for 9V conversion in the present system. Objects of Invention Thus the main object of the present invention is to provide a robust converter which can withstand high ambient temperature, dusty atmosphere and voltage fluctuation. Another object of the present invention is to provide directly 23v AC (which is available at site ) to the converter so that use of an external power supply of c)v DC can be avoided. 3 A further object of the present invention is to provide indication to show the on going data transmission between the PC based programming unit and PLC. Summary of Invention Thus according to the main aspect of the present invention there is provided a system for conversion of data communication protocol from TTY (TELETYPE) to RS 232C , which is capable of withstanding high ambient temperature, dust and voltage fluctuation, the system comprising: i) a plurality of transistors; ii) means for isolation of input and out put; iii) one or more single layered printed circuit board: and iv) means to indicate power and communication failure Detailed description of Invention The system according to the invention is a converter designed in a single side printed circuit board. The means for isolation of input and out put are opto isolators and the means to indicate power and communication failure are Light Emitting Diodes (LED). The PLC and PC sides of the system (converter) are provided with means to receive, transmit and ground signals. Such means include 9-pin D type male connector at the PLC which connects directly to 9-pin D type male/female connector in the PC side and a 25-pin D Type female connector at the PC side which connects directly to 15-pin D type male/female connector in the PLC side. The programmable controller (PLC) has a current port and the PC port through the PLC to communicate with RS-232C which works on voltage. Hence the invented converter converts the voltage to current protocol. To do any change in the program of PLC or to view the status of 4 any input and output it is required to establish communication between the PLC and PC .The converter of the present invention is the link between the PLC and PC. The system uses regulators in the power supply which preside constant out put of+/- 12 DC and the power supply is through single cable due to internal conversion. The 9-pin D type male connector receives signal at PLC side and transmits them to the transistors for driving the data signals, to the Light Emitting Diodes which indicates power failure(if any), the signals then pass through the opto isolator which isolates the input signal and then to the 25-pin D Type female connector at the PC side; while the output signal passes from the PC side through another opto isolator, through transistor and LED which indicates the communication failure then to the PLC side. The invention is now illustrated with reference to non limiting accompanying drawings Brief Description of Accompanying Drawings Figure-1 shows a regulated power supply unit Figure-2 shows the actual converter Figure 3 shows cable connection from TTY to PLC Detailed Description of Figures Fig 1. indicates the regulated power supply unit for the present invention. It is built around two regulator integrated circuit 7812 and 7912 which give constant output of+/- 12v DC. In figure 2 at the extreme left side there is a 9 pin D-type male connector in which only pin nos. 2, 3 and 5 are used to transmit, receive and ground. This is connected through a 3 core, 1.5 mm cable directly to the 9-pin female/male D-type connector in the PC side. 5 4 numbers of LEDs marked as R,R, G,G, are put to show the data communication. These LEDs blink, when the data transmission is going on. TR1, TR2, TR3 are three nos. of transistors used for driving the data signals. Ul and U2 are two optoisolators used having isolation between the input and output. At the extreme right side is a 25-pin female D-type connector in which pin no. 8, 10, 21 and 22 are used. This is connected through a 5 or 6 core x 1.5mm cable to the 15 pin D-type connector of a PLC which is shown in figure-3. Figure 3 shows a interface cable only which is connected between the PLC and the converter. As most of the CPU or the processor of the PLC is having a 15 pin female connector, the present system has a male 15 pin connector connecting the interface cable. 6 We claim 1. A system for conversion of data communication protocol from TTY (TELETYPE) to RS 232C , which is capable of withstanding high ambient temperature, dust and voltage fluctuation, the system comprising: i) a plurality of transistors; ii) means for isolation of input and out put: iii) one or more single layered printed circuit board; and iv) means to indicate power and communication failure 2. A system as claimed in claim 1 wherein the said means for isolation of input and out put are opto isolators. 3. A system as claimed in claims 1 or 2 wherein the said means to indicate power and communication failure are Light Emitting Diodes. 4. A system as claimed in any preceding claim wherein the PLC and PC sides are provided with means to receive, transmit and ground signals. 5. A system as claimed in claim 4 wherein the said means at the PLC side is a 9-pin D type male connector which connects directly to 9-pin D type male/female connector in the PC side. 6. A system as claimed in claim 4 wherein the said means at the PC side is a 25-pin D Type female connector which connects directly to 15-pin D type male/female connector in the PLC side, 7. A system as claimed in any preceding claim wherein regulators are used in the power supply to provide constant output of+/- 12DC. 7 8. A system as claimed in any preceding claim wherein the9-pin D type male connector has signal receiving end at the PLC side and adapted to transmit signals to the transistors for driving the data signals to the Light Emitting Diodes which indicate power failure, the signals thereafter pass through the opto isolator which isolates the input signal and then to the 25-pin D Type female connector at the PC side; while the output signal passes from the PC side through another opto isolator, through transistor and LED which indicates the communication failure then to the PLC side. 9. A system as claimed in any preceding claims wherein the power supply is through a single cable. A system for conversion of data communication protocol from TTY (TELETYPE)-to RS 232C. which is capable of withstanding high ambient temperature, dust and voltage fluctuation, the system comprising: a plurality of transistors: means for isolation of input and out put: one or more single layered printed circuit board: and means to indicate power and communication failure. The system of the present invention provides directly 23v AC (which is available at site) to the converter so that use of an external power supply of 9v DC can be avoided. It further provides indication to show the on going data transmission between the PC based programming unit and PLC.

Full Text

Field of Invention
The present invention relates to a system of conversion of data communication protocol from TTY (TELETYPE) to RS 232C. More particularly the present invention relates to a robust converter which is transistor based, single layered and opto isolated and thus adapted ic withstand high ambient temperature, dusty atmosphere and voltage fluctuation. The system also avoids the use of separate external power supply.
Background and prior art
RS232C is the most common data communication protocol in use today, as it is the most successful interface standard implemented today. Most of the programmable logic controller or intelligent sensors have TTY interface for programming device and operator panel.
In a manufacturing plant, different types of programmable controller (PLC) and intelligent sensors are used for achieving automation. In the early days, only dedicated type of programming units was available, in which monopoly of the supplier existed, Without a programming unit, a user cannot interact with the PLC. Not only this, a user cannot see the application program.
Demand for PC (Personal Computer) based programming unit has grown and users opted for PC based programming unit.
However most of the reputed manufacturer of PLC has TTY interface in their central processing unit through which an operator or a user can interact with the PLC. In the PC side, 9 pin, RS-232C is the most common data communication protocol being used, as it is the most successful interface standard implemented today. Hence, the necessity of converting this TTY to RS-232C became a must.
The conventional converter for converting this TTY to RS-232C, which is available in the market has many drawbacks. Such converter is designed using integrated circuit type IC 232CP
2

and requires an external DC power supply of 9v, which is not able to withstand the dusty atmosphere, high temperature and voltage fluctuation.
IC based systems available in the market can withstand temperature only up to 45C. Moreover the conventional system consists of a single IC 232CP. a multilayered Printed circuit Board (PCB), which is very small in size. Being multilayered and small it is more prone to dust as dust cannot be easily removed. Also , being multilayered and small . it is very difficult to repair in case of failure. Further the conventional converter based on IC 232CP is expensive. The converter presently available is directly connected to field. Hence the CPU is prone to damage every six months or so. Further with the conventional converter there is no regulation of voltage fluctuations since the system is direct feed to the converter. In addition the conventional system does not have any indicator for power failure or communication failure.
In view of the above short comings there is a need for converter which can withstand high ambient temperature and dust, is cost effective, can be easily cleaned, does not need separate power supply and is provided with adequate indicators for power failure and communication failure.
The inventors have now found a system that uses transistors instead of integrated circuit; is single layered instead of multilayered and is optoisolated to protect CPU and thus the system of the present invention can overcome the above problems associated with the conventional systems. Further being provided with internal conversion no separate power supply ie no adaptor is required for 9V conversion in the present system.
Objects of Invention
Thus the main object of the present invention is to provide a robust converter which can withstand high ambient temperature, dusty atmosphere and voltage fluctuation.
Another object of the present invention is to provide directly 23v AC (which is available at site ) to the converter so that use of an external power supply of c)v DC can be avoided.
3

A further object of the present invention is to provide indication to show the on going data transmission between the PC based programming unit and PLC.
Summary of Invention
Thus according to the main aspect of the present invention there is provided a system for conversion of data communication protocol from TTY (TELETYPE) to RS 232C , which is capable of withstanding high ambient temperature, dust and voltage fluctuation, the system comprising:
i) a plurality of transistors;
ii) means for isolation of input and out put;
iii) one or more single layered printed circuit board: and
iv) means to indicate power and communication failure
Detailed description of Invention
The system according to the invention is a converter designed in a single side printed circuit board. The means for isolation of input and out put are opto isolators and the means to indicate power and communication failure are Light Emitting Diodes (LED).
The PLC and PC sides of the system (converter) are provided with means to receive, transmit and ground signals. Such means include 9-pin D type male connector at the PLC which connects directly to 9-pin D type male/female connector in the PC side and a 25-pin D Type female connector at the PC side which connects directly to 15-pin D type male/female connector in the PLC side.
The programmable controller (PLC) has a current port and the PC port through the PLC to communicate with RS-232C which works on voltage. Hence the invented converter converts the voltage to current protocol. To do any change in the program of PLC or to view the status of
4

any input and output it is required to establish communication between the PLC and PC .The converter of the present invention is the link between the PLC and PC.
The system uses regulators in the power supply which preside constant out put of+/- 12 DC and the power supply is through single cable due to internal conversion.
The 9-pin D type male connector receives signal at PLC side and transmits them to the transistors for driving the data signals, to the Light Emitting Diodes which indicates power failure(if any), the signals then pass through the opto isolator which isolates the input signal and then to the 25-pin D Type female connector at the PC side; while the output signal passes from the PC side through another opto isolator, through transistor and LED which indicates the communication failure then to the PLC side.
The invention is now illustrated with reference to non limiting accompanying drawings Brief Description of Accompanying Drawings
Figure-1 shows a regulated power supply unit
Figure-2 shows the actual converter
Figure 3 shows cable connection from TTY to PLC
Detailed Description of Figures
Fig 1. indicates the regulated power supply unit for the present invention. It is built around two regulator integrated circuit 7812 and 7912 which give constant output of+/- 12v DC.
In figure 2 at the extreme left side there is a 9 pin D-type male connector in which only pin nos. 2, 3 and 5 are used to transmit, receive and ground. This is connected through a 3 core, 1.5 mm cable directly to the 9-pin female/male D-type connector in the PC side.
5

4 numbers of LEDs marked as R,R, G,G, are put to show the data communication. These LEDs blink, when the data transmission is going on.
TR1, TR2, TR3 are three nos. of transistors used for driving the data signals. Ul and U2 are two optoisolators used having isolation between the input and output.
At the extreme right side is a 25-pin female D-type connector in which pin no. 8, 10, 21 and 22 are used. This is connected through a 5 or 6 core x 1.5mm cable to the 15 pin D-type connector of a PLC which is shown in figure-3.
Figure 3 shows a interface cable only which is connected between the PLC and the converter. As most of the CPU or the processor of the PLC is having a 15 pin female connector, the present system has a male 15 pin connector connecting the interface cable.
6

We claim
1. A system for conversion of data communication protocol from TTY (TELETYPE) to RS
232C , which is capable of withstanding high ambient temperature, dust and voltage
fluctuation, the system comprising:
i) a plurality of transistors;
ii) means for isolation of input and out put:
iii) one or more single layered printed circuit board; and iv) means to indicate power and communication failure
2. A system as claimed in claim 1 wherein the said means for isolation of input and out put
are opto isolators.
3. A system as claimed in claims 1 or 2 wherein the said means to indicate power and
communication failure are Light Emitting Diodes.
4. A system as claimed in any preceding claim wherein the PLC and PC sides are provided
with means to receive, transmit and ground signals.
5. A system as claimed in claim 4 wherein the said means at the PLC side is a 9-pin D type
male connector which connects directly to 9-pin D type male/female connector in the PC
side.
6. A system as claimed in claim 4 wherein the said means at the PC side is a 25-pin D Type
female connector which connects directly to 15-pin D type male/female connector in the
PLC side,
7. A system as claimed in any preceding claim wherein regulators are used in the power
supply to provide constant output of+/- 12DC.
7

8. A system as claimed in any preceding claim wherein the9-pin D type male connector has
signal receiving end at the PLC side and adapted to transmit signals to the transistors for
driving the data signals to the Light Emitting Diodes which indicate power failure, the
signals thereafter pass through the opto isolator which isolates the input signal and then
to the 25-pin D Type female connector at the PC side; while the output signal passes from
the PC side through another opto isolator, through transistor and LED which indicates the
communication failure then to the PLC side.
9. A system as claimed in any preceding claims wherein the power supply is through a
single cable.

A system for conversion of data communication protocol from TTY (TELETYPE)-to RS 232C. which is capable of withstanding high ambient temperature, dust and voltage fluctuation, the system comprising: a plurality of transistors: means for isolation of input and out put: one or more single layered printed circuit board: and means to indicate power and communication failure. The system of the present invention provides directly 23v AC (which is available at site) to the converter so that use of an external power supply of 9v DC can be avoided. It further provides indication to show the on going data transmission between the PC based programming unit and PLC.

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Patent Number

207174

Indian Patent Application Number

00152/KOL/2004

PG Journal Number

21/2007

Publication Date

25-May-2007

Grant Date

23-May-2007

Date of Filing

31-Mar-2004

Name of Patentee

STEEL AUTHORITY OF INDIA

Applicant Address

ROURLKELA STEEL PLANT, STEEL AUTHORITY OF INDIA LTD, ROURKELE-769011, ORISSA,

Inventors:

#	Inventor's Name	Inventor's Address
1	PANDA PRADIP KUMAR	ROURLKELA STEEL PLANT, STEEL AUTHORITY OF INDIA LTD, ROURKELE-769011, ORISSA,
2	KOTAMRAJU VENKATRAMANA	ROURLKELA STEEL PLANT, STEEL AUTHORITY OF INDIA LTD, ROURKELE-769011, ORISSA, INDIA

PCT International Classification Number

G06F 13/40

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA