JP3070836B2 - Air conditioner data communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having an indoor unit and an outdoor unit connected to a common commercial power supply line, and more particularly, to one of the commercial power supply lines and a communication line. The present invention relates to a data communication device of an air conditioner that performs data communication using two lines, one line provided in the air conditioner.

[0002]

2. Description of the Related Art Communication between an indoor unit and an outdoor unit of an air conditioner requires a pair of communication lines, but it is desirable that the number of lines provided for communication be small. For this reason, a conventional technique of performing communication between an indoor unit and an outdoor unit using a common commercial power supply line and one line provided for communication is disclosed in Japanese Patent Publication No. 1-57264 (1st edition). No. 7-96948 (No. 2).
Of the prior art).

That is, in the first prior art, a photocoupler and a thyristor are provided on each of the indoor unit side and the outdoor unit side. Further, the light emitting diode of the photocoupler and the thyristor are connected in series on the indoor unit side and the outdoor unit side, respectively, so that the directions of the currents are the same. The cathode of the thyristor on the side of the indoor unit and the anode of the thyristor on the side of the outdoor unit are connected by a serial signal line. Further, the anode of the light emitting diode on the indoor unit side is connected to one line of the commercial power supply, and the cathode of the light emitting diode on the outdoor unit side is connected to the other line of the commercial power supply. That is,
The configuration is such that the commercial power supply line also functions as one of the pair of communication lines. Therefore, it is possible to perform bidirectional communication between the indoor unit and the outdoor unit only by adding one serial signal line for communication.

In the second prior art, a photocoupler having a bidirectional light emitting diode and a phototriac which is a bidirectional switching element are provided on each of an indoor unit side and an outdoor unit side. Provided. Further, on each of the indoor unit side and the outdoor unit side, the light emitting diode of the photocoupler and the triac of the phototriac are connected in series between the lines of the commercial power supply.
Further, a connection point between the light emitting diode on the indoor unit side and the triac and a connection point between the light emitting diode on the outdoor unit side and the triac are connected by a signal line. In other words, the configuration is such that the commercial power supply line also functions as one of the pair of communication lines. For this reason, it is possible to perform bidirectional communication between the indoor unit and the outdoor unit only by adding one signal line for communication.

[0005]

However, both the first prior art and the second prior art have the following problems. That is, the waveform of the commercial power supply is used for communication. Therefore, when transmitting data, it is necessary to synchronize the transmission timing with the waveform of the commercial power supply. For this reason, a detection circuit for detecting zero clock of the commercial power supply is required, so that the configuration of the communication circuit is complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to detect a zero cross of a commercial power supply at the time of transmission using a photocoupler for receiving data from a communication partner. Accordingly, it is an object of the present invention to provide a data communication device of an air conditioner which can omit a dedicated circuit for detecting a zero cross of a commercial power supply.

[0007]

According to a first aspect of the present invention, there is provided a data communication device for an air conditioner having an indoor unit and an outdoor unit connected to a common commercial power supply line. The present invention is applied to an air conditioner in which an indoor unit and an outdoor unit perform bidirectional communication using a pair of one of the commercial power supply lines and a signal line, and one of the indoor unit and the outdoor unit is used as a second unit. When one device is used as the second device and the other is used as the second device, and one of the commercial power lines is used as a common line, the first device includes a first Zener diode having an anode connected to the signal line. , A second Zener diode having a cathode connected to the cathode of the first Zener diode and an anode connected to the shared line, and a first switch connected in parallel to the second Zener diode. A first photocoupler having an element and a cathode of a light emitting diode connected to an anode of a first zener diode, and an anode of the light emitting diode connected to a cathode of a first zener diode or an anode of a second zener diode; The second device includes a third Zener diode having an anode connected to the signal line, a fourth Zener diode having a cathode connected to the cathode of the third Zener diode, and an anode connected to the shared line. A Zener diode, a second switching element connected in parallel to the third Zener diode, a cathode of the light emitting diode connected to an anode of the fourth Zener diode, and an anode of the light emitting diode connected to a fourth Zener diode. Cathode or anode of third Zener diode A second photocoupler connected to the first photocoupler, and a current-limiting resistor is provided in each of the current path of the light-emitting diode of the first photocoupler and the current path of the light-emitting diode of the second photocoupler. The terminal is connected to the other of the commercial power supply lines, and the other terminal is provided with a resistor connected to the signal line.

For simplicity, the forward voltage of the Zener diode and the ON voltage of the switching element are set to 0.
Assuming V, the operation is shown below. When both the first and second switching elements are off and the polarity of the commercial power supply is a polarity at which a Zener voltage is generated in the first Zener diode, a current flows through the light emitting diode of the first photocoupler. Also, if the polarity of the commercial power supply is
When the polarity of the Zener diode causes a Zener voltage, a current flows through the light emitting diode of the second photocoupler. Therefore, when not transmitting, the first and second photocouplers operate as a zero-crossing detection circuit. On the other hand, even if the connection of the first switching element is closed for the transmission operation, the first photocoupler operates as a zero-cross detection circuit. Also, even if the connection of the second switching element is closed for the transmission operation,
The second photocoupler operates as a zero cross detection circuit. When the connection of the first switching element is closed, when the polarity of the signal line becomes positive, the voltage between the shared line and the signal line becomes 0V. Therefore,
No current flows through the light emitting diode of the second photocoupler. That is, when the polarity of the signal line is positive, when the connection of the first switching element is opened, a current flows to the light emitting diode of the second photocoupler, and when the connection of the first switching element is closed, the second switching element is closed. No current flows through the light emitting diode of the photocoupler. That is, the opening and closing of the connection of the first switching element is detected by the second photocoupler. Further, when the polarity of the signal line becomes negative, the opening and closing of the connection of the second switching element is detected by the first photocoupler.

A data communication device for an air conditioner according to a second aspect of the present invention has an indoor unit and an outdoor unit connected to a common commercial power supply line, and has one of the commercial power supply lines and a signal. The present invention is applied to an air conditioner in which an indoor unit and an outdoor unit perform bidirectional communication using a pair of lines with a line, and one of the indoor unit and the outdoor unit is used as a first device and the other is used as a second device. When one of the commercial power supply lines is used as a common line, the first device includes a fifth Zener diode having a cathode connected to the signal line and an anode connected to the anode of the fifth Zener diode. Connected with the cathode connected to the common line
, A third switching element connected in parallel with the sixth Zener diode, an anode of the light emitting diode is connected to a cathode of the fifth Zener diode, and a cathode of the light emitting diode is connected to the fifth Zener diode.
And a third photocoupler connected to the anode of the Zener diode or the cathode of the sixth Zener diode. The second device includes a seventh Zener diode having a cathode connected to the signal line, and an anode having Seventh
An eighth Zener diode connected to the anode of the Zener diode and a cathode connected to the shared line, and a fourth connected in parallel to the seventh Zener diode.
A fourth switching element, wherein the anode of the light emitting diode is connected to the cathode of the eighth Zener diode, and the cathode of the light emitting diode is connected to the anode of the eighth Zener diode or the cathode of the seventh Zener diode. A photo-coupler; a current-limiting resistor is provided in each of a current path of the light-emitting diode of the third photo-coupler and a current path of the light-emitting diode of the fourth photo-coupler; And the other terminal is provided with a resistor connected to the signal line.

For simplicity of description, the forward voltage of the Zener diode and the ON voltage of the switching element are zero.
Assuming V, the operation is shown below. When both the first and fourth switching elements are off and the polarity of the commercial power supply is a polarity that generates a Zener voltage in the fifth Zener diode, a current flows through the light emitting diode of the third photocoupler. Also, the polarity of the commercial power supply is
When the polarity of the Zener diode causes a Zener voltage, a current flows through the light emitting diode of the fourth photocoupler. Therefore, when not transmitting, the first and fourth photocouplers operate as a zero-crossing detection circuit. On the other hand, even if the connection of the third switching element is closed for the transmission operation, the third photocoupler operates as a zero-cross detection circuit. Further, even if the connection of the fourth switching element is closed for the transmission operation,
The fourth photocoupler operates as a zero-cross detection circuit. Further, when the connection of the third switching element is closed, when the polarity of the signal line becomes negative, the voltage between the shared line and the signal line becomes 0V. Therefore, no current flows through the light emitting diode of the fourth photocoupler. That is, when the polarity of the signal line becomes negative, when the connection of the third switching element is opened,
When a current flows through the light emitting diode of the photocoupler and the connection of the third switching element is closed, no current flows through the light emitting diode of the fourth photocoupler. That is, the opening and closing of the connection of the third switching element is detected by the fourth photocoupler. When the polarity of the signal line is positive, the opening and closing of the connection of the fourth switching element is detected by the third photocoupler.

A data communication device for an air conditioner according to a third aspect of the present invention has an indoor unit and an outdoor unit connected to a common commercial power supply line, and has one of the commercial power supply lines and a signal. The present invention is applied to an air conditioner in which an indoor unit and an outdoor unit perform bidirectional communication using a pair of lines with a line, and one of the indoor unit and the outdoor unit is used as a first device and the other is used as a second device. When one of the commercial power supply lines or the signal line is a first line and the other is a second line, the anode is connected to the first line in the first device. The ninth Zener diode, the cathode connected to the cathode of the ninth Zener diode, the anode connected to the tenth Zener diode connected to the second line, and the tenth Zener diode. A fifth switching element connected to the column, a cathode of the light emitting diode is connected to an anode of the ninth zener diode, and an anode of the light emitting diode is connected to a cathode of the ninth zener diode or an anode of the tenth zener diode. A fifth photocoupler connected to the first device, the second device includes an eleventh Zener diode having a cathode connected to the first line, and an anode connected to an anode of the eleventh Zener diode. A twelfth Zener diode having a cathode connected to the second line, a sixth switching element connected in parallel to the twelfth Zener diode,
An anode of the light emitting diode is connected to a cathode of the eleventh Zener diode, and a cathode of the light emitting diode is connected to an anode of the eleventh Zener diode or a cathode of the twelfth Zener diode.
And a current limiting resistor is provided in each of the current path of the light emitting diode of the fifth photo coupler and the current path of the light emitting diode of the sixth photo coupler, and one terminal is connected to the commercial power supply. The configuration is such that a resistor connected to the other of the lines and the other terminal connected to the signal line is provided.

For simplicity of description, the forward voltage of the Zener diode and the on-voltage of the switching element are zero.
Assuming V, the operation is shown below. When both the first and sixth switching elements are off and the polarity of the commercial power supply is a polarity at which a Zener voltage is generated at the ninth Zener diode, a current flows through the light emitting diode of the fifth photocoupler. Also, the polarity of the commercial power supply is the first
When the first zener diode has a polarity that generates a zener voltage, a current flows through the light emitting diode of the sixth photocoupler. Therefore, when not transmitting, the first and sixth photocouplers operate as a zero-cross detection circuit. On the other hand, even if the connection of the fifth switching element is closed for the transmission operation, the fifth photocoupler operates as a zero-cross detection circuit. Further, even if the connection of the sixth switching element is closed for the transmission operation,
The sixth photocoupler operates as a zero cross detection circuit. When the connection of the fifth switching element is closed, when the polarity of the first line becomes positive,
The voltage between the second line and the second line is 0V. Therefore, no current flows through the light emitting diode of the sixth photocoupler. That is, when the polarity of the first line is positive, when the connection of the fifth switching element is opened, a current flows through the light emitting diode of the sixth photocoupler,
When the connection of the switching element is closed, no current flows through the light emitting diode of the sixth photocoupler. That is,
Opening and closing of the connection of the fifth switching element is detected by the sixth photocoupler. Further, when the polarity of the first line is negative, the opening and closing of the connection of the sixth switching element is detected by the fifth photocoupler.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described with reference to the drawings. FIG. 1 is a circuit diagram showing an electrical connection of the first embodiment of the data communication device of the air conditioner according to the first aspect of the present invention.

The first embodiment is roughly divided into an indoor unit 1
1, an outdoor unit 12, and a signal line 13 connecting the indoor unit 11 and the outdoor unit 12. The indoor unit 11 and the outdoor unit 12 share, for example, commercial power lines 14 and 15 of 200 V or the like. The indoor unit 11 corresponds to the first device described in claim 1, and the outdoor unit 12 corresponds to the second device described in claim 1.
The commercial power supply line 14 of the commercial power supply lines 14 and 15 corresponds to the common line described in claim 1.
That is, the indoor unit 11 and the outdoor unit 12 are connected to the signal line 13.
And the common line 14 are used to communicate with each other. It should be noted that the mechanical unit of the indoor unit 11 and a control unit that controls the mechanical unit, and the mechanical unit of the outdoor unit 12 and a control unit that controls the mechanical unit are not illustrated.

The anode of the first Zener diode D1 is connected to the end of the signal line 13 on the indoor unit 11 side. The cathode of the first Zener diode D1 is connected to the cathode of the second Zener diode D2. Then, the second Zener diode D
The two anodes are connected to a common line 14.

The first switching element connected in parallel to the second zener diode D2 is a switching element that limits the zener voltage to a voltage near 0 V when a zener voltage is generated in the second zener diode D2. I just need. Therefore, in the present embodiment, the first switching element is connected to the phototransistor Q1 of the photocoupler 3.
And That is, the collector of the phototransistor Q1 is connected to the cathode of the second Zener diode D2. Further, the emitter of the phototransistor Q1 is connected to the anode of the second Zener diode D2.

The anode of the light emitting diode D7 for controlling the switching of the phototransistor Q1 is connected to a positive power supply via a current limiting resistor R3.
The cathode of the light emitting diode D7 is connected to the collector of the transistor Q4, and the emitter of the transistor Q4 is grounded. And the transistor Q4
The output of the communication control unit 4 is guided to the base of the device via a resistor R4. Therefore, when the output of the communication control unit 4 goes high, the phototransistor Q1 is turned on. Further, when the output of the communication control unit 4 becomes L level, the phototransistor Q1 is turned off.

The first photocoupler 1 is an element that detects a zero cross of a commercial power supply and receives data transmitted from the outdoor unit 12. For this reason, the cathode of the light emitting diode D5 of the first photocoupler 1
Is connected to the anode of the Zener diode D1. The anode of the light emitting diode D5 is connected to the first Zener diode D5 via a current limiting resistor R1.
1 cathode.

The collector of the phototransistor Q3 whose switching is controlled by the light emitting diode D5 is connected to a positive power supply. The emitter of the phototransistor Q3 is grounded via the resistor R2.
The emitter of the phototransistor Q3 is guided to the communication control unit 4 as an output of zero-cross detection and an output of data from the outdoor unit 12. Therefore, when a current flows through the light emitting diode D5, an H level is sent to the communication control unit 4. When no current flows through the light emitting diode D5, an L level is sent to the communication control unit 4.

The communication control unit 4 is a block for transmitting data from a control unit (not shown) to the outdoor unit 12. Further, it receives data transmitted from the outdoor unit 12 and outputs the data to a control unit (not shown). In addition, a resistor R <b> 9 having one terminal connected to the signal line 13 and the other terminal connected to the commercial power line 15 is provided.

The anode of the third Zener diode D3 is connected to the end of the signal line 13 on the outdoor unit 12 side. Further, the cathode of the fourth Zener diode D4 is connected to the cathode of the third Zener diode D3. Then, the fourth Zener diode D
4 is connected to the common line 14.

The second switching element connected in parallel with the third zener diode D3 is a switching element that limits the zener voltage to a voltage near 0 V when a zener voltage is generated in the third zener diode D3. I just need. Therefore, in the present embodiment, the second switching element is connected to the phototransistor Q2 of the photocoupler 5.
And That is, the collector of the phototransistor Q2 is connected to the cathode of the third Zener diode D3. Further, the emitter of the phototransistor Q2 is connected to the anode of the third Zener diode D3.

The anode of the light emitting diode D8 for controlling the switching of the phototransistor Q2 is connected to a positive power supply via a current limiting resistor R5.
The cathode of the light emitting diode D8 is connected to the collector of the transistor Q6, and the emitter of the transistor Q6 is grounded. And the transistor Q6
The output of the communication control unit 6 is led to the base of the communication controller 6 via the resistor R7. Therefore, when the output of the communication control unit 6 goes high, the phototransistor Q2 is turned on. Further, when the output of the communication control unit 6 becomes L level, the phototransistor Q2 is turned off.

The second photocoupler 2 is an element that detects a zero cross of a commercial power supply and receives data transmitted from the indoor unit 11. For this reason, the cathode of the light emitting diode D6 of the second photocoupler 2 is connected to the fourth
Is connected to the anode of the Zener diode D4. The anode of the light emitting diode D6 is connected to the fourth Zener diode D6 via a current limiting resistor R6.
4 is connected to the cathode.

The collector of the phototransistor Q5 whose switching is controlled by the light emitting diode D6 is connected to a positive power supply. The emitter of the phototransistor Q5 is grounded via the resistor R8.
The emitter of the phototransistor Q5 is guided to the communication control unit 6 as an output of zero-cross detection and an output of data from the indoor unit 11. Therefore, when a current flows through the light emitting diode D6, an H level is sent to the communication control unit 6. When no current flows through the light emitting diode D6, the L level is sent to the communication control unit 6.

The communication controller 6 is a block for transmitting data from a controller (not shown) to the indoor unit 11. In addition, it receives data transmitted from the indoor unit 11 and outputs the data to a control unit (not shown).

FIG. 3 is a timing chart showing the waveforms of the main signals of the first embodiment. The group of waveforms indicated by 51 indicates the waveforms of the main signals when the phototransistor Q1 is turned off. A group of waveforms indicated by 52 indicates waveforms of main signals when the phototransistor Q1 is turned on. The operation of the first embodiment will be described with reference to FIG. 3 as necessary. In the following, for simplicity of description, the forward voltages of the first to fourth Zener diodes D1 to D4 and the ON voltages of the phototransistors Q1 and Q2 as the first and second switching elements are as follows. It is assumed that the voltage is 0V.

It is assumed that both the first and second switching elements are off, that is, both the phototransistors Q1 and Q2 are off (this will be described with reference to the waveform group indicated by 51 in FIG. 3). At this time, the line 14 of the commercial power supply
(T1) when the polarity of the line 15 with respect to
), A current flows from the shared line 14 to the signal line 13. Therefore, the second Zener diode D
2 has a voltage of 0 V between the anode and cathode (21
reference). Further, the voltage between the anode and the cathode of the fourth Zener diode D4 also becomes 0 V (see 23).

On the other hand, a Zener voltage is generated in the first Zener diode D1 (see 22). Also, the third
The Zener diode D3 also generates a Zener voltage. Therefore, the voltage of the signal line 13 becomes equal to the Zener voltage of the first Zener diode D1 (see 13 in FIG. 3). As a result, current flows through the light emitting diode D5 of the first photocoupler 1, and no current flows through the light emitting diode D6 of the second photocoupler 2.

In a period (t2 and the like) in which the polarity of the line 15 with respect to the line 14 of the commercial power supply is positive (such as t2), current flows from the signal line 13 to the shared line 14. Therefore, the voltage between the anode and the cathode of the first Zener diode D1 becomes 0 V (see 22). Further, the voltage between the anode and the cathode of the third Zener diode D3 also becomes 0V.

On the other hand, a Zener voltage is generated in the second Zener diode D2 (see 21). Also, the fourth
The Zener diode D4 also generates a Zener voltage (see 23). Therefore, the voltage of the signal line 13 is
It becomes equal to the Zener voltage of the fourth Zener diode D4 (see 13 in FIG. 3). As a result, current flows through the light emitting diode D6 of the second photocoupler 2, and no current flows through the light emitting diode D5 of the first photocoupler 1.

That is, the phototransistors Q1 and Q2
Are turned off, the output of the first photocoupler 1 (the emitter of the phototransistor Q3) outputs a zero-cross detection output. Also, the output of the second photocoupler 2 (the emitter of the phototransistor Q5)
Also outputs a zero-cross detection output.

Now, suppose that the phototransistor Q1 is turned on (with reference to the waveform group indicated by 52 in FIG. 3).
explain). In this case, during the period (t2 or the like) during which the polarity of the line 15 with respect to the line 14 of the commercial power supply is
A current flows from the signal line 13 to the shared line 14. Therefore, the voltage between the anode and the cathode of the first Zener diode D1 becomes 0 V (see 22). Further, the voltage between the anode and the cathode of the third Zener diode D3 also becomes 0V.

The voltage between the cathode and the anode of the second Zener diode D2 is equal to the voltage of the phototransistor Q1.
Is turned on, the voltage becomes 0 V (see 21). Therefore, the voltage of the signal line 13 becomes 0V. As a result, the voltage between the anode and the cathode of the fourth Zener diode D4 also becomes 0 V (see 23). Therefore, no current flows through the light emitting diode D6 of the second photocoupler 2. Further, the light emitting diode D5 of the first photocoupler 1
No current flows.

On the other hand, during a period in which the polarity of the line 15 with respect to the line 14 of the commercial power supply is negative (such as t1), the voltage between the anode and the cathode of the second Zener diode D2 is 0 V (see 21). The voltage between the anode and cathode of the fourth Zener diode D4 is 0
V (see 23). On the other hand, a Zener voltage is generated in the first Zener diode D1 (see 22). Also, a Zener voltage is generated in the third Zener diode D3. For this reason, the voltage of the signal line 13 becomes the first
Is equal to the Zener voltage of the Zener diode D1. As a result, a current flows through the light emitting diode D5 of the first photocoupler 1. Further, no current flows through the light emitting diode D6 of the second photocoupler 2.

That is, even when the phototransistor Q1 is turned on (phototransistor Q2 is turned off) in order for the indoor unit 11 to transmit data to the outdoor unit 12, the output of the first photocoupler 1 (the emitter of the phototransistor Q3). ) Outputs a zero-cross detection output. Similarly, even when the outdoor unit 12 turns on the phototransistor Q2 (turns off the phototransistor Q1) in order to transmit data to the indoor unit 11, the output of the second photocoupler 2 (the emitter of the phototransistor Q5). ) Outputs a zero-cross detection output.

Attention is now directed to a period (t2 and the like) in which the polarity of the line 15 with respect to the line 14 of the commercial power supply is positive. When the phototransistor Q1 is off, the voltage at the cathode of the fourth Zener diode D4 becomes equal to the Zener voltage (see 23 of 51). Therefore, a current flows through the light emitting diode D6 of the second photocoupler 2. However, when the phototransistor Q1 is turned on, the voltage between the anode and the cathode of the fourth Zener diode D4 becomes 0 V (see 23 of 52). Therefore, no current flows through the light emitting diode D6 of the second photocoupler 2.

That is, in a period (t2 or the like) in which the polarity of the line 15 with respect to the line 14 of the commercial power supply is positive (such as t2), when the phototransistor Q1 is turned off, a current flows through the light emitting diode D6, and the emitter of the phototransistor Q5 has the H level. Becomes When the phototransistor Q1 is turned on, no current flows through the light emitting diode D6,
The emitter of the phototransistor Q5 goes low.
That is, the ON / OFF state of the phototransistor Q1 is detected as the output of the emitter of the phototransistor Q5. That is, data is transmitted from the indoor unit 11 to the outdoor unit 12.

For this reason, the communication control unit 4 performs transmission during a period (t2 or the like) during which the polarity of the line 15 with respect to the line 14 of the commercial power supply is positive (ie, during a period when the output of the phototransistor Q3 is at the L level). Do. That is, when the output of the phototransistor Q3 changes from the H level to the L level, data output to the base of the transistor Q4 starts. The data output to the base of the transistor Q4 is transmitted to the communication control unit 6 via the light emitting diode D7, the phototransistor Q1, the signal line 13, the light emitting diode D6, and the phototransistor Q5.

The above operation is performed from the outdoor unit 12 side to the indoor unit 1
The same applies to the case where data is transmitted to the first side. More specifically, the communication control unit 6 determines that the polarity of the line 15 with respect to the line 14 of the commercial power supply is negative (such as t1).
That is, transmission is performed during a period when the output of the phototransistor Q5 is at the L level. That is, when the output of the phototransistor Q5 changes from H level to L level,
Output of data to the base of the transistor Q6 is started. The data output to the base of the transistor Q6 is
Light emitting diode D8, phototransistor Q2, signal line 13, light emitting diode D5, phototransistor Q
3 and transmitted to the communication control unit 4.

This embodiment employs a configuration in which 8-bit data is transmitted in each unit period such as the period t1 or the period t2 in order to speed up data transmission.

FIG. 2 is a circuit diagram showing an electrical connection of a data communication device of an air conditioner according to a second embodiment of the present invention. The second embodiment is different from the configuration (first embodiment) shown in FIG. 1 in that the connection of the anode of the light emitting diode D5 is changed and the connection of the anode of the light emitting diode D6 is changed. For this reason,
The configuration will be described only for the changed part, and the description of the same part will be omitted.

The cathode of the diode D9 is connected to the anode of the light emitting diode D5. Further, the anode of the diode D9 is connected to the anode of the second Zener diode D2 via the resistor R1 for limiting the current. Also, the anode of the light emitting diode D6 has:
The cathode of the diode D10 is connected. Also,
The anode of diode D10 is connected to a current limiting resistor R
6 is connected to the anode of the third Zener diode D3.

Diodes D9 and D10 in the above configuration
The action of is shown below. If the diode D9 is omitted,
During a period in which the polarity of the line 15 with respect to the line 14 of the commercial power supply is positive (such as t2), a voltage generated between the signal line 13 and the shared line 14 is applied to the light emitting diode D5 as a reverse voltage, and light is emitted. The diode D5 may be destroyed. The diode D9 protects the light emitting diode D5 from breakdown by dividing the reverse voltage and reducing the reverse voltage applied to the light emitting diode D5. The same applies to the diode D10, and the light-emitting diode D6 is protected from destruction by reducing the reverse voltage applied to the light-emitting diode D6.

The second embodiment has the above configuration. Therefore, when a zener voltage is generated in the third zener diode D3 (when a zener voltage is generated in the first zener diode D1), a current flows through the light emitting diode D5, and at other times, no current flows through the light emitting diode D5. . In addition, a Zener voltage is generated in the second Zener diode D2 (the fourth Zener diode D4).
A Zener voltage is generated), the light emitting diode D6
Current flows through the light emitting diode D6 at other times.
No current flows through For this reason, the operation of the first photocoupler 1 and the operation of the second photocoupler 2 are the same as in the first embodiment. Therefore, the communication operation between the indoor unit 11 and the outdoor unit 12 is the same as the operation of the first embodiment, and the description of the operation will be omitted.

FIG. 4 is a circuit diagram showing the electrical connection of the first and second embodiments of the data communication device for an air conditioner according to the second aspect of the present invention. Has a configuration using the blocks 1A and 2A among the blocks 1A, 1B, 2A and 2B. Also, the second
The embodiment has a configuration using blocks 1B and 2B. Also, in this figure, the same reference numerals as in FIG. 1 are assigned to blocks and lines having the same configuration as that shown in FIG.

First, a first embodiment having a configuration using the blocks 1A and 2A will be described. Signal line 13
Is connected to a cathode of a fifth Zener diode D11. The anode of the sixth Zener diode D12 is connected to the anode of the fifth Zener diode D11. The cathode of the sixth Zener diode D12 is connected to the shared line 14.

The collector is the sixth Zener diode D1
The phototransistor Q11 connected to the cathode of No. 2 and the emitter connected to the anode of the sixth Zener diode D12 is an element corresponding to the third switching element. That is, the phototransistor Q11
Restricts the Zener voltage to a voltage near 0 V when a Zener voltage is generated in the sixth Zener diode D12.

The third photocoupler 33 is an element that detects a zero cross of a commercial power supply and receives data transmitted from the outdoor unit 12. Therefore, the anode of the light emitting diode D15 of the third photocoupler 33 is connected to the cathode of the fifth Zener diode D11. Further, the cathode of the light emitting diode D15 is connected to the anode of the fifth Zener diode D11 via a resistor R11 for limiting the current.

The cathode of a seventh Zener diode D13 is connected to the end of the signal line 13 on the outdoor unit 12 side. Further, the anode of the eighth Zener diode D14 is connected to the anode of the seventh Zener diode D13. The cathode of the eighth Zener diode D14 is connected to the common line 14.

The collector is the seventh Zener diode D1
The phototransistor Q12 connected to the cathode of No. 3 and the emitter connected to the anode of the seventh Zener diode D13 is an element corresponding to the fourth switching element. That is, the phototransistor Q12
Restricts the Zener voltage to a voltage near 0 V when a Zener voltage is generated in the seventh Zener diode D13.

The fourth photocoupler 34 is an element that detects the zero cross of the commercial power supply and receives the data transmitted from the indoor unit 11. Therefore, the anode of the light emitting diode D16 of the fourth photocoupler 34 is connected to the cathode of the eighth Zener diode D14. Further, the cathode of the light emitting diode D16 is connected to the anode of the eighth Zener diode D14 via the resistor R12 for limiting the current.

The light emitting diode (not shown) corresponding to the phototransistor Q11 has the same connection as the light emitting diode D7 shown in FIG. The light emitting diode (not shown) corresponding to the phototransistor Q12 has the same connection as the light emitting diode D8 shown in FIG. The phototransistor (not shown) corresponding to the light emitting diode D15 of the third photocoupler 33 has the same connection as the phototransistor Q3 shown in FIG. The phototransistor (not shown) corresponding to the light emitting diode D16 of the fourth photocoupler 34 has the same connection as the phototransistor Q5 shown in FIG.

The operation of the first embodiment having the above configuration will be described. When the phototransistors Q11 and Q12 are both turned off, the third photocoupler 33 and the fourth photocoupler 34 detect a zero cross. Also,
When the phototransistor Q12 is turned off and the phototransistor Q11 is turned on, that is, when data is transmitted from the indoor unit 11 to the outdoor unit 12, the third photocoupler 33 detects a zero cross. Further, when the phototransistor Q11 is turned off and the phototransistor Q12 is turned on, that is, when data is transmitted from the outdoor unit 12 to the indoor unit 11, the fourth photocoupler 34 detects a zero cross.

When the polarity of the signal line 13 is negative and a Zener voltage is generated in the sixth Zener diode D12, a current flows through the light emitting diode D16. On the other hand, when the phototransistor Q11 is turned on and no Zener voltage is generated in the sixth Zener diode D12, no current flows through the light emitting diode D16. When the polarity of the signal line 13 is positive, no current flows through the light emitting diode D16. Therefore, when the polarity of the signal line 13 is negative, the on / off state of the phototransistor Q11 is detected by the fourth photocoupler.
That is, data is transmitted from the indoor unit 11 to the outdoor unit 12.

When the polarity of the signal line 13 is positive and a Zener voltage is generated in the seventh Zener diode D13, a current flows through the light emitting diode D15. On the other hand, when the phototransistor Q12 is turned on and no Zener voltage is generated in the seventh Zener diode D13, no current flows through the light emitting diode D15. When the polarity of the signal line 13 is negative, no current flows through the light emitting diode D15.
Therefore, when the polarity of the signal line 13 is positive, the ON / OFF state of the phototransistor Q12 is detected by the third photocoupler 33.
That is, data is transmitted from the outdoor unit 12 to the indoor unit 11.

Hereinafter, a second embodiment having a configuration using the blocks 1B and 2B will be described. In the second embodiment, the blocks 1A and 2A of the first embodiment are
The configuration is changed to blocks 1B and 2B. That is, only the connection on the cathode side of the light emitting diodes D15 and D16 is changed. Therefore, the configuration will be described only for the changed part, and the description of the same part will be omitted.

The anode of the diode D17 is connected to the cathode of the light emitting diode D15. The cathode of the diode D17 is connected to a resistor R1 for limiting the current.
1 is connected to the cathode of the sixth Zener diode D12. The anode of the diode D18 is connected to the cathode of the light emitting diode D16. Further, the cathode of the diode D18 is connected to the cathode of the seventh Zener diode D13 via a resistor R12 for limiting a current.

Diodes D17 and D1 in the above configuration
The operation of No. 8 will be described below. If the diode D17 is omitted, a voltage generated between the signal line 13 and the shared line 14 is applied to the light emitting diode D15 as a reverse voltage during a period in which the polarity of the line 14 of the commercial power supply is positive, and D15 may be destroyed.
The diode D17 protects the light emitting diode D15 from destruction by dividing the reverse voltage and reducing the reverse voltage applied to the light emitting diode D15. The same applies to the diode D18, and the light-emitting diode D16 is protected from destruction by reducing the reverse voltage applied to the light-emitting diode D16.

The second embodiment has the above configuration. Therefore, when the Zener voltage is generated in the seventh Zener diode D13 (the Zener voltage is generated in the fifth Zener diode D11), the light emitting diode D15
Current flows through the light emitting diode D1 at other times.
No current flows through 5. Further, when a Zener voltage is generated in the sixth Zener diode D12 (Zener voltage is generated in the eighth Zener diode D14), a current flows through the light emitting diode D16, and at other times, no current flows through the light emitting diode D16. . For this reason, the operation of the third photocoupler 33 and the operation of the fourth photocoupler 34 are the same as in the first embodiment. Therefore, the communication operation between the indoor unit 11 and the outdoor unit 12 is the same as the operation of the first embodiment.

FIG. 5 is a circuit diagram showing the electrical connection of the first and second embodiments of the data communication device of the air conditioner according to the third aspect of the present invention. Has a configuration using the blocks 3A and 4A among the blocks 3A, 3B, 4A and 4B. Also, the second
The embodiment has a configuration using blocks 3B and 4B. The signal line 13 is a first line according to the third aspect, and the shared line 14 is a second line according to the third aspect. Also, in FIG. 3, blocks and lines having the same configuration as that shown in FIG.
Are given the same reference numerals as those given in.

First, a first embodiment having a configuration using the blocks 3A and 4A will be described. An anode of a ninth Zener diode D21 is connected to an end of the signal line (first line) 13 on the indoor unit 11 side.
The cathode of the ninth Zener diode D21 is connected to the cathode of the tenth Zener diode D22. Then, the tenth Zener diode D
The anode 22 is connected to the shared line (second line) 14.

The collector is the tenth Zener diode D
The phototransistor Q21 connected to the cathode of the transistor 22 and the emitter connected to the anode of the tenth Zener diode D22 is an element corresponding to the fifth switching element. That is, the phototransistor Q2
1 limits the zener voltage to a voltage near 0 V when a zener voltage is generated in the tenth zener diode D22.

The fifth photocoupler 35 is an element that detects a zero cross of the commercial power supply and receives data transmitted from the outdoor unit 12. For this reason, the cathode of the light emitting diode D25 of the fifth photocoupler 35 is connected to the anode of the ninth Zener diode D21. Further, the anode of the light emitting diode D25 is connected to the cathode of the ninth Zener diode D21 via the resistor R21 for limiting the current.

The cathode of the eleventh Zener diode D23 is connected to the end of the signal line 13 on the outdoor unit 12 side. The eleventh Zener diode D2
The twelfth Zener diode D24
Anodes are connected. The cathode of the twelfth Zener diode D24 is connected to the common line 14.

The collector is the twelfth Zener diode D
The phototransistor Q22 connected to the cathode of the transistor 24 and the emitter connected to the anode of the twelfth Zener diode D24 is an element corresponding to the sixth switching element. That is, the phototransistor Q2
2 limits the Zener voltage to a voltage near 0 V when a Zener voltage is generated in the twelfth Zener diode D24.

The sixth photocoupler 36 is an element that detects the zero cross of the commercial power supply and receives the data transmitted from the indoor unit 11. For this reason, the anode of the light emitting diode D26 of the sixth photocoupler 36 is connected to the cathode of the eleventh zener diode D23. Further, the cathode of the light emitting diode D26 is connected to the anode of the eleventh Zener diode D23 via the resistor R22 for limiting the current.

The light emitting diode (not shown) corresponding to the phototransistor Q21 has the same connection as the light emitting diode D7 shown in FIG. The light emitting diode (not shown) corresponding to the phototransistor Q22 has the same connection as the light emitting diode D8 shown in FIG. The phototransistor (not shown) corresponding to the light emitting diode D25 of the fifth photocoupler 35 has the same connection as the phototransistor Q3 shown in FIG. Further, a phototransistor (not shown) corresponding to the light emitting diode D26 of the sixth photocoupler 36 has the same connection as the phototransistor Q5 shown in FIG.

The operation of the first embodiment having the above configuration will be described. When the phototransistors Q21 and Q22 are both turned off, the fifth photocoupler 35 and the sixth photocoupler 36 detect a zero cross. Also,
When the phototransistor Q22 is turned off and the phototransistor Q21 is turned on, that is, when data is transmitted from the indoor unit 11 to the outdoor unit 12, the fifth photocoupler 35 detects a zero cross. When the phototransistor Q21 is turned off and the phototransistor Q22 is turned on, that is, when data is transmitted from the outdoor unit 12 to the indoor unit 11, the sixth photocoupler 36 detects a zero cross.

In the case where the polarity of the signal line 13 is positive, when a Zener voltage is generated in the tenth Zener diode D22, a current flows through the light emitting diode D26. On the other hand, when the phototransistor Q21 is turned on and no Zener voltage is generated in the tenth Zener diode D22, no current flows through the light emitting diode D26. When the polarity of the signal line 13 is negative, no current flows through the light emitting diode D26. Therefore, when the polarity of the signal line 13 is positive, the on / off state of the phototransistor Q21 is
This is detected by the sixth photocoupler 36. That is, data is transmitted from the indoor unit 11 to the outdoor unit 12.

When the polarity of the signal line 13 is negative and a Zener voltage is generated in the twelfth Zener diode D24, a current flows through the light emitting diode D25. On the other hand, when the phototransistor Q22 is turned on and no Zener voltage is generated in the twelfth Zener diode D24, no current flows through the light emitting diode D25. When the polarity of the signal line 13 is positive, no current flows through the light emitting diode D25. Therefore, when the polarity of the signal line 13 is negative, the ON / OFF state of the phototransistor Q22 is detected by the fifth photocoupler 35. That is, data is transmitted from the outdoor unit 12 to the indoor unit 11.

Hereinafter, a second embodiment having a configuration using the blocks 3B and 4B will be described. In the second embodiment, the blocks 3A and 4A of the first embodiment are
The configuration is changed to blocks 3B and 4B. That is, only the connection of the light emitting diode D25 on the anode side and the connection of the light emitting diode D26 on the cathode side are changed. Therefore, the configuration will be described only for the changed part, and the description of the same part will be omitted.

The cathode of the diode D27 is connected to the anode of the light emitting diode D25. The anode of the diode D27 is connected to a resistor R2 for limiting the current.
1 is connected to the anode of the tenth Zener diode D22. The anode of the light emitting diode D26 is connected to the anode of the diode D28. Further, the cathode of the diode D28 is connected to the cathode of the twelfth Zener diode D24 via a resistor R22 for limiting a current.

The diodes D27 and D2 in the above configuration
The operation of No. 8 will be described below. If the diode D27 is omitted, a voltage generated between the signal line 13 and the shared line 14 is applied to the light emitting diode D25 as a reverse voltage during a period in which the polarity of the line 15 of the commercial power supply is positive, and D25 may be destroyed.
The diode D27 protects the light emitting diode D25 from destruction by dividing the reverse voltage and reducing the reverse voltage applied to the light emitting diode D25. The same applies to the diode D28, and the light-emitting diode D26 is protected from destruction by reducing the reverse voltage applied to the light-emitting diode D26.

The second embodiment has the above configuration. Therefore, a Zener voltage is generated in the twelfth Zener diode D24 (the ninth Zener diode D21).
A Zener voltage is generated), the light emitting diode D2
5 and at other times the light emitting diode D
No current flows through 25. When a Zener voltage is generated in the tenth Zener diode D22 (when a Zener voltage is generated in the eleventh Zener diode D23),
A current flows through the light emitting diode D26, and at other times, no current flows through the light emitting diode D26. Therefore, the operation of the fifth photocoupler 35 and the operation of the sixth photocoupler 36 are the same as in the first embodiment. Therefore, the communication operation between the indoor unit 11 and the outdoor unit 12 is the same as the operation of the first embodiment.

The third embodiment of the present invention has been described in connection with the case where the signal line 13 is the first line and the shared line 14 is the second line.
A configuration in which the signal line 13 is a second line and the shared line 14 is a first line (connection lines A and C are shared lines 1
4 and the connection lines B and D are connected to the signal line 13).

[0077]

According to the data communication device of the air conditioner according to the first aspect of the present invention, one of the indoor unit and the outdoor unit is connected to the first unit.
When the other device is a second device and one of the commercial power lines is a shared line, the first device includes a first Zener diode having an anode connected to a signal line, and a cathode. Is connected to the cathode of the first Zener diode, the second Zener diode whose anode is connected to the shared line, the first switching element connected in parallel to the second Zener diode, and the cathode of the light emitting diode. A second device connected to an anode of a first Zener diode, wherein the anode of the light emitting diode comprises a first photocoupler connected to a cathode of the first Zener diode or to an anode of a second Zener diode; Has a third Zener diode having an anode connected to the signal line, and a cathode having a third Zener diode. A fourth Zener diode connected to the cathode of the diode, the anode connected to the shared line, a second switching element connected in parallel to the third Zener diode, and a cathode of the light emitting diode connected to the fourth Zener diode A second photocoupler connected to the anode of the fourth Zener diode or the anode of the third Zener diode.
A current limiting resistor is provided in each of the current path of the light emitting diode of the first photocoupler and the current path of the light emitting diode of the second photocoupler, and one terminal is connected to the other of the commercial power supply lines. The other terminal is provided with a resistor connected to the signal line.

According to a second aspect of the present invention, there is provided a data communication device for an air conditioner, comprising an indoor unit and an outdoor unit connected to a common commercial power line, wherein one of the commercial power lines is connected to a signal. The present invention is applied to an air conditioner in which an indoor unit and an outdoor unit perform bidirectional communication using a pair of lines with a line, and one of the indoor unit and the outdoor unit is used as a first device and the other is used as a second device. When one of the commercial power supply lines is used as a common line, the first device includes a fifth Zener diode having a cathode connected to the signal line and an anode connected to the anode of the fifth Zener diode. Connected with the cathode connected to the common line
, A third switching element connected in parallel with the sixth Zener diode, an anode of the light emitting diode is connected to a cathode of the fifth Zener diode, and a cathode of the light emitting diode is connected to the fifth Zener diode.
And a third photocoupler connected to the anode of the Zener diode or the cathode of the sixth Zener diode. The second device includes a seventh Zener diode having a cathode connected to the signal line, and an anode having Seventh
An eighth Zener diode connected to the anode of the Zener diode and a cathode connected to the shared line, and a fourth connected in parallel to the seventh Zener diode.
A fourth switching element, wherein the anode of the light emitting diode is connected to the cathode of the eighth Zener diode, and the cathode of the light emitting diode is connected to the anode of the eighth Zener diode or the cathode of the seventh Zener diode. A photo-coupler; a current-limiting resistor is provided in each of a current path of the light-emitting diode of the third photo-coupler and a current path of the light-emitting diode of the fourth photo-coupler; And the other terminal is provided with a resistor connected to the signal line.

A data communication device for an air conditioner according to a third aspect of the present invention has an indoor unit and an outdoor unit connected to a common commercial power supply line, and has one of the commercial power supply lines and a signal. The present invention is applied to an air conditioner in which an indoor unit and an outdoor unit perform bidirectional communication using a pair of lines with a line, and one of the indoor unit and the outdoor unit is used as a first device and the other is used as a second device. When one of the commercial power supply lines or the signal line is a first line and the other is a second line, the anode is connected to the first line in the first device. The ninth Zener diode, the cathode connected to the cathode of the ninth Zener diode, the anode connected to the tenth Zener diode connected to the second line, and the tenth Zener diode. A fifth switching element connected to the column, a cathode of the light emitting diode is connected to an anode of the ninth zener diode, and an anode of the light emitting diode is connected to a cathode of the ninth zener diode or an anode of the tenth zener diode. A fifth photocoupler connected to the first device, the second device includes an eleventh Zener diode having a cathode connected to the first line, and an anode connected to an anode of the eleventh Zener diode. A twelfth Zener diode having a cathode connected to the second line, a sixth switching element connected in parallel to the twelfth Zener diode,
An anode of the light emitting diode is connected to a cathode of the eleventh Zener diode, and a cathode of the light emitting diode is connected to an anode of the eleventh Zener diode or a cathode of the twelfth Zener diode.
And a current limiting resistor is provided in each of the current path of the light emitting diode of the fifth photo coupler and the current path of the light emitting diode of the sixth photo coupler, and one terminal is connected to the commercial power supply. The configuration is such that a resistor connected to the other of the lines and the other terminal connected to the signal line is provided.

That is, the present invention has the above configuration. For this reason, at the time of standby and at the time of transmission, the zero-cross of the commercial power supply is detected by the photocoupler that receives data from the communication partner. Therefore, it is possible to omit a dedicated circuit for detecting the zero cross of the commercial power supply.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an electrical connection of a first embodiment of a data communication device of an air conditioner according to the first aspect of the present invention.

FIG. 2 is a circuit diagram showing an electrical connection of a data communication device of an air conditioner according to a second embodiment of the present invention.

FIG. 3 is a timing chart showing waveforms of main signals according to the embodiment.

FIG. 4 is a circuit diagram showing an electrical connection of the data communication device of the air conditioner according to the second embodiment of the present invention.

FIG. 5 is a circuit diagram showing an electrical connection of the data communication device of the air conditioner according to the third embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 first photocoupler 2 second photocoupler 11 indoor unit 12 outdoor unit 13 signal line 14 commercial power line (common line) 15 commercial power line 33 third photocoupler 34 fourth photocoupler 35 fifth photo Coupler 36 Sixth photocoupler D1 First Zener diode D2 Second Zener diode D3 Third Zener diode D4 Fourth Zener diode D5 Light emitting diode of first photocoupler D6 Light emitting diode of second photocoupler D11 Fifth Zener diode D12 Sixth Zener diode D13 Seventh Zener diode D14 Eighth Zener diode D21 Ninth Zener diode D22 Tenth Zener diode D23 Eleventh Zener diode D24 Twelfth Zener -Diode Q1 First switching element Q2 Second switching element Q11 Third switching element Q12 Fourth switching element Q21 Fifth switching element Q22 Sixth switching element R1, R2 Current limiting resistors R11, R12 Current limiting Resistors R21, R22 Current limiting resistors

Claims (3)

(57) [Claims] An indoor unit and an outdoor unit having an indoor unit and an outdoor unit connected to a common commercial power supply line, and using a pair of one of the commercial power supply lines and a signal line. In an air conditioner that performs two-way communication, when one of the indoor unit or the outdoor unit is a first device and the other is a second device, and one of the commercial power lines is a shared line, A first Zener diode having an anode connected to the signal line, a second Zener diode having a cathode connected to the cathode of the first Zener diode, and an anode connected to the shared line; A first switching element connected in parallel to the second Zener diode; a cathode of the light emitting diode connected to an anode of the first Zener diode; A diode having an anode connected to the cathode of the first Zener diode or a first photocoupler connected to the anode of the second Zener diode; the second device includes a third device having an anode connected to the signal line. A fourth Zener diode having a cathode connected to the cathode of the third Zener diode and an anode connected to the shared line; and a second switching element connected in parallel to the third Zener diode. A light emitting diode having a cathode connected to an anode of a fourth zener diode, and an anode of the light emitting diode being connected to a cathode of a fourth zener diode or a second photocoupler connected to an anode of a third zener diode. The current path of the light emitting diode of the first photocoupler and A current limiting resistor is provided in each of the current paths of the light emitting diodes of the second photocoupler and one terminal is connected to the other of the commercial power supply lines, and the other terminal is connected to the signal line. A data communication device for an air conditioner, characterized in that a resistance is provided. 2. An indoor unit and an outdoor unit having an indoor unit and an outdoor unit connected to a common commercial power supply line, and using a pair of one of the commercial power supply lines and a signal line. In an air conditioner that performs two-way communication, when one of the indoor unit or the outdoor unit is a first device and the other is a second device, and one of the commercial power lines is a shared line, The first device includes a fifth Zener diode having a cathode connected to the signal line, a sixth Zener diode having an anode connected to the anode of the fifth Zener diode, and a cathode connected to the shared line, A third switching element connected in parallel with the sixth Zener diode, and an anode of the light emitting diode connected to a cathode of the fifth Zener diode, A third photocoupler connected to the anode of the fifth Zener diode or the cathode of the sixth Zener diode, wherein the second device has a seventh photocathode having a cathode connected to the signal line; An eighth Zener diode having an anode connected to the anode of the seventh Zener diode, a cathode connected to the shared line, and a fourth switching element connected in parallel to the seventh Zener diode. An anode of the light-emitting diode is connected to a cathode of the eighth Zener diode, and a cathode of the light-emitting diode is connected to a fourth photocoupler connected to the anode of the eighth Zener diode or the cathode of the seventh Zener diode. And the current path and the light emitting diode of the third photocoupler. A current limiting resistor is provided in each of the current paths of the light emitting diodes of the fourth photocoupler, one terminal is connected to the other of the commercial power supply lines, and the other terminal is connected to the signal line. A data communication device for an air conditioner, characterized in that a resistance is provided. 3. An indoor unit and an outdoor unit having an indoor unit and an outdoor unit connected to a common commercial power supply line, and using a pair of one of the commercial power supply lines and a signal line. In an air conditioner that performs two-way communication, one of an indoor unit and an outdoor unit is a first device and the other is a second device, and one of the commercial power supply lines or one of the signal lines is When the first line and the other line are the second line, the first device includes a ninth Zener diode having an anode connected to the first line, and a cathode having a cathode connected to the ninth Zener diode. A tenth Zener diode having an anode connected to the second line, a fifth switching element connected in parallel to the tenth Zener diode, and a light emitting diode Is connected to the anode of the ninth Zener diode, and the anode of the light emitting diode is connected to the cathode of the ninth Zener diode or the anode of the ninth Zener diode.
A fifth photocoupler connected to the anode of the Zener diode of the first embodiment, the second device includes an eleventh Zener diode having a cathode connected to the first line, and an anode of the eleventh Zener diode. A twelfth Zener diode connected to the anode and the cathode connected to the second line, a sixth switching element connected in parallel to the twelfth Zener diode, and an anode of the light emitting diode connected to the eleventh Zener diode The cathode of the light emitting diode is connected to the anode of the eleventh Zener diode or the cathode of the twelfth Zener diode.
And a current limiting resistor is provided in each of the current path of the light emitting diode of the fifth photo coupler and the current path of the light emitting diode of the sixth photo coupler, and one terminal is connected to the commercial power supply. A data communication device for an air conditioner, comprising: a resistor connected to the other of the lines and the other terminal connected to a signal line.