JPH0450781B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a serial data transfer device used, for example, in an air conditioner having a plurality of indoor units, for transmitting and receiving serial data between two devices connected by an AC power line.

A conventional device of this type was constructed as shown in FIG. 1 or 2.

That is, in the apparatus of FIG. 1, one side (hereinafter referred to as
Two serial signal lines SL, separate from the power supply line AC, are provided between device 1 on the transmitting side (hereinafter referred to as the receiving side) and device 2 on the other side (hereinafter referred to as the receiving side). data was being transferred at the level).

However, with this device, not only was the connection between devices 1 and 2 complicated with four wires, but the voltage levels on the transmitting and receiving sides were different, and incorrect wiring could lead to destruction of the device. .

Furthermore, in the apparatus shown in FIG. 2, device 1 and device 2 are connected by a power line AC, and serial data is transferred using this single power line.

In other words, the serial signal is modulated by the modulation circuit 3 on the transmitting side.
The receiving side takes out the modulated signal from the power line AC, and demodulates it in the demodulation circuit 4 to obtain data.

This device serves as both a signal line and a power supply line, so there is no need to worry about wiring, but it requires a modulation circuit 3 and a demodulation circuit 4, making both transmitting and receiving circuits complicated and expensive.

This invention was made in view of the above circumstances.One signal line is provided between two devices connected by an AC power line, and the device on one side has a level corresponding to the transferred data. Further, a transfer data signal generating means is provided for generating a transfer data signal in which one bit is synchronized with one cycle of the AC power supply voltage, and the above-mentioned signal line is connected between one of the AC power lines and the signal line in the equipment on one side. Serial data signal generation means is provided to turn on and off electricity in accordance with the transfer data signal and to generate a serial data signal depending on the presence or absence of a half-cycle signal of the AC power supply voltage, and in the device on the other side, the other of the above signal line and the AC power supply line is provided. The object of the present invention is to provide a serial data transfer device that has a simple circuit configuration, is inexpensive, and can prevent damage to the device due to incorrect wiring by providing a detection means connected between the device and the device to detect the serial data signal. shall be.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 3, a device 1 and a device 2 are connected by an alternating current power line AC, and one signal line SL is provided between the devices 1 and 2.

The transmitting side device 1 includes a control circuit 10 and a serial data signal generation circuit 11.

The control circuit 10 has a transfer data signal generating means, and has a level corresponding to the data to be transferred (hereinafter referred to as transfer data), and transfers data in which one bit is synchronized with one cycle of the AC power supply voltage. Create a data signal.

The serial data signal generation circuit 11 is connected between one end of the AC power supply line AC and one end of the signal line SL, and turns on and off power supply according to the transfer data signal created by the control circuit 10, thereby adjusting the AC power supply voltage. A serial data signal is created depending on the presence or absence of a half-cycle waveform.

The receiving side device 2 includes a control circuit 12 and a detection circuit 13.

The detection circuit 13 is connected between the other end of the signal line SL and the other end of the AC power line AC, and is connected to the device 1.
It detects the serial data signal transferred from.

The control circuit 12 determines transfer data from the serial data signal detected by the detection circuit 13.

Here, a specific circuit of the device 1 on the transmitting side is shown in FIG. 4, and a specific circuit of the device 2 on the receiving side is shown in FIG.

First, serial data signal generation circuit 1 of device 1
1, the cathode of a diode _D1 is connected to one side L1 of the power line AC, and the anode of _the diode _D1 is connected to one end of the signal line SL via a switch SW and a resistor _R1 . The switch SW is turned on and off depending on the level of the transfer data signal generated by the control circuit 10.

Note that a photocoupler, a photothyristor, or the like is actually used as the switch SW.

On the other hand, the detection circuit 13 of the device 2
Connect _the light-emitting diode on the input side of the photocoupler PC between the other end of SL and the other L2 of the AC power line AC via the resistor _R2 , and connect the diode _D2 of the polarity shown in parallel with the light-emitting diode. are doing.
Furthermore, the collector of the phototransistor on the secondary side of the photocoupler PC is connected to the positive side terminal of the DC power supply V _DD , and the emitter of the phototransistor is connected to a resistor.
Grounded via _R3 . The voltage generated across the resistor R ₃ is then supplied to the control circuit 12 .

Next, the operation in the above configuration will be explained.

First, the operation of the device 1 will be explained with reference to FIG.

In the device 1, the control circuit 10 creates a transfer data signal b that corresponds to the level of the transfer data and in which one bit is synchronized with one cycle of the AC power supply voltage a. Then, when the transfer data signal b is at the logic "1" level, the switch SW of the serial data signal generation circuit 11 is turned on. Further, when the transfer data signal b is at the logic "0" level, the switch SW of the serial data signal generation circuit 11 is turned off.

In this way, the switch SW turns on or off,
In addition, by the action of the diode _D1 , a serial data signal c is created with a positive level half-cycle waveform of the AC power supply voltage a. This serial data signal c is sent to the signal line SL.

On the other hand, the operation of the device 2 will be explained with reference to FIG.

In the device 2, when the serial data signal c at the positive voltage level is present on the signal line SL during the positive level period of the AC power supply voltage a, a current flows through the light emitting diode of the photocoupler PC of the detection circuit 13.
At this time, the light emitting diode emits light and the phototransistor of the photocoupler PC turns on.

When the phototransistor turns on, a voltage is generated across resistor _R3 .

In this way, a logic "1" level voltage and a logic "0" level voltage are generated in the resistor _R3 , that is, the serial data signal c is detected by the detection circuit 13, and the transfer data signal b corresponding to the serial data signal c is detected.
is taken into the control circuit 12.

The control circuit 12 determines the transfer data from the captured transfer data signal d.

In this way, data transfer is possible with a simple configuration of just providing one more signal line SL in addition to the power supply line AC.

Furthermore, since the serial data signal transmitted through the signal line SL handles the half-cycle waveform of the AC power supply voltage a, the signal line SL itself is strong against the power supply voltage level, and the signal line SL may be damaged due to incorrect wiring. Even if connected to the power line AC, there is no fear of damage to the serial data signal generation circuit 11 or the detection circuit 13.

Furthermore, since the serial data signal has a high voltage level, it is resistant to noise and can avoid erroneous transfer.

Furthermore, the circuit configuration is simple and inexpensive.

By the way, in the above embodiment, the device 1 on one side
is used for sending, and device 2 on the other side is used for receiving, and data is transferred only in one direction.In that case, a command must be transferred from device 1 to device 2, and device 2 operates according to the command. Even if it is possible to do so, it is impossible to notify equipment 1 of an abnormality or request of equipment 2. For this reason, the device 1 has no choice but to rely on a self-protection circuit that follows a certain sequence.

Therefore, an embodiment that enables bidirectional data transfer between the devices 1 and 2 is shown in FIG. In FIG. 8, the same parts as in FIGS. 3 to 5 are given the same reference numerals, and detailed explanation thereof will be omitted.

Here, in one cycle of AC power supply voltage,
A positive level half-cycle waveform is used as a serial data signal from device 1 to device 2, and a negative level half-cycle waveform is used as a serial data signal from device 2 to device 1.

In other words, device 1 and device 2 are connected to the AC power line.
They are connected by AC, and one signal line SL is provided between the devices 1 and 2.

The device 1 includes a control circuit 10, a serial data signal generation circuit 11 ₁ , and a detection circuit 13 ₁ .

The control circuit 10 has a transfer data signal generating means, and generates a transfer data signal having a level corresponding to the transfer data and in which one bit is synchronized with one cycle of the AC power supply voltage.

The serial data signal generation circuit ₁₁₁ has the same configuration as the serial data signal generation circuit 11 of the above embodiment, and is connected to one side of the AC power line AC.
It is connected between L ₁ and one end of the signal line SL, turns on and off electricity according to the transfer data signal created by the control circuit 10, and outputs a serial data signal with a half-cycle waveform of the positive level of the AC power supply voltage. create.

The detection circuit 13 ₁ is the detection circuit 1 of the above embodiment.
It has the same configuration as 3 and is connected between one end of the signal line SL and one side _L1 of the AC power line AC, and detects the serial data signal transferred from the device 2.

Further, the control circuit 10 determines transfer data from the serial data signal detected by the detection circuit 13 ₁ .

The device 2 includes a control circuit 12, a serial data signal generation circuit 11 ₂ , and a detection circuit 13 ₂ .

The control circuit 12 has a transfer data signal generating means, and generates a transfer data signal having a level corresponding to the transfer data and in which one bit is synchronized with one cycle of the AC power supply voltage.

The serial data signal generation circuit ₁₁₂ has the same configuration as the serial data signal generation circuit 11 of the above embodiment, and is connected to the other side of the AC power supply line AC.
It is connected between L ₂ and the other end of the signal line SL, turns on and off electricity according to the transfer data signal created by the control circuit 12, and generates a serial data signal with a negative level half-cycle waveform of the AC power supply voltage. Create.

The detection circuit 13 ₂ is the detection circuit 1 of the above embodiment.
It has the same configuration as No. 3, is connected between the other end of the signal line SL and the _other end of the AC power line AC, and detects the serial data signal transferred from the device 1.

Further, the control circuit 12 determines transfer data from the serial data signal detected by the detection circuit 13 ₂ .

Explain the action.

First, data transfer from device 1 to device 2 will be explained.

In the device 1 (see FIG. 6), the control circuit 10 creates a transfer data signal b that corresponds to the level of the transfer data and in which one bit is synchronized with one cycle of the AC power supply voltage a. Then, when the transfer data signal b is at the logic "1" level, the switch SW of the serial data signal generation circuit ₁₁₁ is turned on.
Further, when the transfer data signal b is at the logic "0" level, the switch SW of the serial data signal generation circuit ₁₁₁ is turned off.

In this way, the serial data signal c is created using the positive level half-cycle waveform of the AC power supply voltage a. This serial data signal c is connected to the signal line
Sent to SL.

In the device 2 (see FIG. 7), when the serial data signal c at the positive voltage level is present on the signal line SL during the positive level period of the AC power supply voltage a, the light emitting diode of the photocoupler PC in the detection circuit ₁₃₂ emits light. The phototransistor of the photocoupler PC turns on.

In this way, the serial data signal c is transmitted to the detection circuit 1.
3 ₂ , and the transfer data signal d corresponding to the serial data signal c is taken into the control circuit 12.

The control circuit 12 determines the transfer data from the captured transfer data signal d.

Next, data transfer from device 2 to device 1 will be explained.

In the device 2, a control circuit 12 creates a transfer data signal corresponding to the level of the transfer data and in which one bit is synchronized with one cycle of the AC power supply voltage a. Then, the transfer data signal is logic “1”
When the level, the serial data signal generation circuit 11
Switch SW ₂ is turned on. Further, when the transfer data signal is at the logic "0" level, the switch SW of the serial data signal generation circuit ₁₁₂ is turned off.

In this way, a serial data signal with a negative level half-cycle waveform of the AC power supply voltage a is created. This serial data signal is connected to signal line SL
will be sent to.

In the device 1, when a negative voltage level serial data signal is present on the signal line SL during the negative level period of the AC power supply voltage a, the light emitting diode of the photocoupler PC in the detection circuit ₁₃₁ emits light.
The phototransistor of the photocoupler PC turns on.

In this way, the serial data signal is transmitted to the detection circuit 13.
₁ is detected, and a transfer data signal corresponding to the serial data signal is taken into the control circuit 10.

The control circuit 10 determines the transfer data from the acquired transfer data signal.

In this way, of one cycle of AC power supply voltage a, the positive level half cycle waveform is used as the serial data signal from device 1 to device 2, and the negative level half cycle waveform is used as the serial data signal from device 2 to device 1. By using it as a signal, the device 1,
Bidirectional data transfer between the two is possible.

Therefore, it is possible to transmit not only commands from one side of the device to the other side of the device, but also abnormalities and requests of the other side of the device to the one side of the device.

As described above, according to the present invention, in two devices connected by an AC power line, one signal line provided between each device and one signal line provided on one side of each device corresponds to transfer data. a transfer data signal generating means for generating a transfer data signal having a level of Serial data signal generation means that is connected and turns on and off electricity according to the transfer data signal to generate a serial data signal depending on the presence or absence of a half cycle signal of the AC power supply voltage, and a serial data signal generation means that connects the signal line and the AC current on the other side of each device. A detection means connected between the other side of the line and detecting the serial data signal is provided, so that a serial data transfer device is provided that has a simple circuit configuration, is inexpensive, and can prevent damage to equipment due to incorrect wiring. can.

[Brief explanation of the drawing]

FIGS. 1 and 2 are block diagrams of a conventional serial data transfer device, FIG. 3 is a block diagram of an embodiment of the present invention, and FIG. 4 is a specific circuit structure of a transmitting device in the same embodiment. 5 is a configuration diagram of a specific circuit of the receiving side equipment in the same embodiment, and FIG.
4 is a signal waveform diagram in FIG. 4, FIG. 7 is a signal waveform diagram in FIG. 5, and FIG. 8 is a configuration diagram of another embodiment of the present invention. 1... Equipment on one side (transmission side), 2... Equipment on the other side (receiving side), 10... Control circuit, 11...
Serial data signal generation circuit, 12...control circuit, 13...detection circuit.

Claims (1)

[Claims] 1 In two devices connected by an AC power line, one signal line provided between each of the devices, and one signal line provided on one side of each device and having a level corresponding to transfer data, and a transfer data signal generating means for generating a transfer data signal whose bits are synchronized with one cycle of the AC power supply voltage; Serial data signal generating means for turning on and off electricity in response to the presence or absence of a half-cycle signal of the AC power supply voltage, and a serial data signal generation means for generating a serial data signal depending on the presence or absence of a half-cycle signal of the AC power supply voltage; 1. A serial data transfer device, comprising: detecting means connected between the devices and detecting the serial data signal.