Conversion Circuit

• US 20090175624A1
• Filed: 03/11/2008
• Published: 07/09/2009
• Est. Priority Date: 03/12/2007
• Status: Active Grant

• Current Assignee: O.Y.L. Research & Development Centre Sdn. Bhd. (Daikin Industries Ltd)
• Original Assignee: O.Y.L. Research & Development Centre Sdn. Bhd. (Daikin Industries Ltd)
• Inventors: Loh, Keen Yong Walter
• Granted Patent: US 8,097,841 B2
• Time in Patent Office: Days
• US Class Current: 398/116
• CPC Class Codes: G06F 13/4072 Drivers or receivers G06F13/4086 takes precedence; for multistate logic circuits H03K19/0002

Abstract

A circuit for converting data of a signal line in the form of logical pulses of current to RS232 level voltages between an air-conditioner and a computer is described. The conversion circuit is able to troubleshoot the communication signals between the indoor unit and outdoor unit of an air-conditioner.

Claims

1. A circuit for converting data of a signal line in the form of logical pulses of current to RS 232 level voltages between an air-conditioner and a computer comprising:

a plurality of opto-couplers each having a phototransistor and a photodiode for inverting and electrically isolating the signals received from the signal line of the air conditioner;

one or more resistors;

a diode for protecting the photodiode against an accidental of reverse voltage;

a serial port for receiving an output voltage from the circuit to be connected to the computer; and

a light emitting diode for indicating the presence of the signals in the circuit.

2. The circuit as claimed in claim 1, wherein the circuit is connected between an indoor unit and an outdoor unit of the air-conditioner and connected to a serial port of said computer.

3. The circuit as claimed in claim 2, wherein the circuit allows the computer to intercept serial data transmitted through a signal line connecting the indoor unit and outdoor unit of the air conditioner for troubleshooting any malfunction in communication between the indoor unit and the outdoor unit of the air-conditioner.

4. The circuit as claimed in claim 1, wherein the opto-couplers include a first opto-coupler, a second opto-coupler, and a third opto-coupler.

5. The circuit as claimed in claim 1, wherein the resistors further include a first resistor and a second resistor.

6. The circuit as claimed in claim 1, wherein the serial port is an RS 232 port having nine pins.

7. The circuit as claimed in claim 1, where the circuit and the components comprising it are connected as follows:

an anode of the photodiode in a first opto-coupler is connected electrically to a signal line of an indoor unit;

a cathode of the photodiode in a second opto-coupler is connected electrically to a signal line of an outdoor unit;

a cathode of the photodiode in the first opto-coupler is connected electrically to an anode of the photodiode in the second opto-coupler;

a collector of the phototransistor in the first opto-coupler is connected electrically to a first end of a first resistor;

an emitter of the phototransistor in the first opto-coupler is connected electrically to pin 5 [Ground (GND)] of a RS232 serial port;

a second end of the first resistor is connected electrically to pin 7 [Request To Sent (RTS)] of the RS232 serial port;

an anode of a photodiode in a third opto-coupler is connected electrically to the first end of the first resistor;

a cathode of the photodiode in the third opto-coupler is connected electrically to pin 5 [Ground (GND)] of the RS232 serial port;

a collector of a phototransistor in the second opto-coupler is connected electrically to pin 4 [Data Terminal Ready (DTR)] of the RS232 serial port;

an emitter of the phototransistor in the second opto-coupler is connected electrically to pin 2 [Request To Sent (RXD) of the RS232 serial port;

a collector of the phototransistor in the third opto-coupler is connected electrically to pin 2 [Receive Data (RXD)] of the RS232 serial port;

an emitter of the phototransistor in the third opto-coupler is connected electrically to pin 3 [Transmit (TXD)] of the RS232 serial port;

an anode of the light emitting diode is connected electrically to pin 2 [Receive Data (RXD)] of the RS232 serial port;

a cathode of the light emitting diode is connected electrically to a first end of a second resistor;

a second end of the second resistor is connected electrically to pin 3 [Transmitted (TXD)] of the RS232 serial port;

a cathode of a diode is connected electrically to the signal line of the indoor unit; and

an anode of the diode is connected electrically to the signal line of the outdoor unit.

8. The circuit as claimed in claim 1, wherein the opto-couplers are configured as a switch and connected to the serial port for transmitting the output voltage.

9. The circuit as claimed in claim 1, wherein the logical pulses are converted to a negative RS 232 voltage when the pulse is low at logical ‘

1’ and

a positive RS 232 voltage when the pulse is high at logical ‘

0’

.

10. A method of generating a logical ‘

0’

by a circuit as claimed in claim 1 into positive RS 232 voltage comprising;

turning on the photodiodes in a first opto-coupler and a second opto-coupler wherein the phototransistor in the first opto-coupler will pull the first end of a first resistor to be low;

turning off the photodiode in a third opto-coupler wherein the phototransistor in the third opto-coupler will disconnect the negative level voltage at pin 3 from pin 2 of the serial port; and

turning on the photodiode in the first opto-coupler and the second opto-coupler wherein the phototransistor in the second opto-coupler will channel the positive level voltage at pin 4 to pin 2 of the serial port.

11. A method of generating logical ‘

1’

by a circuit as claimed in claim 1 into negative RS 232 voltage comprising;

turning off the photodiodes in a first opto-coupler and a second opto-coupler wherein the phototransistor in the second opto-coupler will disconnect the positive level voltage at pin 4 from pin 2 of the serial port;

turning off of the photodiodes in the first opto-coupler and the second opto-coupler wherein the phototransistor in the first opto-coupler will turn off; and

turning on the photodiode in a third opto-coupler wherein the phototransistor in the third opto-coupler will connect the negative level voltage at pin 3 to pin 2 of the serial port.

12. A method of configuring a circuit as claimed in claim 1 for converting data of the signal line in the form of logical pulses of current to RS 232 level voltages between an air conditioner and a computer by means of software comprising:

enabling pin 4 [Data Terminal Ready (DTR)] of the serial port as an output positive level voltage;

enabling pin 7 [Request To Send (RTS)] of the serial port as an output positive level voltage; and

idling pin 3 [Transmitted Data (TXD)] of the serial port as an output negative level voltage.

13. The method as claimed in claim 1, wherein the serial port is a RS232 serial port.