JPS5875948A - Serial data transfer device - Google Patents

Abstract

PURPOSE:To obtain a simple, economical serial data transfer device by providing one signal line between two sets of equipment connected through power lines, and turning on and off an AC power source waveform at a transmission side in every half cycle and thus sending it to the signal line. CONSTITUTION:The equipment 1 on a transmission side and the equipment 2 on a reception side are connected through power lines AC and one signal line SL. A control circuit 10 generates a switching signal which turns on and off according to data in every cycle synchronously with an AC signal on the power lines AC. A current from one power line AC is turned on and off at a switching circuit 11 by the switching signal from the control circuit 10 to be transmitted to the signal line SL. At a reception side, a detecting circuit 13 detects the signal, which is extracted by a control signal synchronizing with the AC signal on the power line AC generated by a control circuit 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a serial data transfer device that is used, for example, in an air conditioner having a plurality of indoor units, and transmits and receives 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 shown in FIG.
In addition, two serial signal lines SL were provided to transfer data at a DC level (voltage level of the control circuit). However, this device has problems such as the complexity of the four wire connections between the devices 1 and 2, the voltage levels between the transmitting side and the receiving side, and incorrect wiring that can lead to destruction of the device.

1. In the device shown in FIG. 2, device 1 and device 2 are connected by a power line AC, and serial data is transferred using this one power line. That is, a serial signal is modulated by a modulation circuit 3 on the transmitting side, and a modulated signal is extracted from the power supply line AC on the receiving side and demodulated by a demodulating 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 the transmitting and receiving circuits complicated, expensive, and rarely used. The present invention was made in view of the above circumstances, and includes a single signal line for transmitting and receiving data between two devices connected by a power supply line.
The AC power waveform is turned on every half cycle on the transmitting side.

By using a circuit configuration that transmits the data signal obtained by turning off on the signal line and detects the data from this signal line on the receiving side, the circuit configuration is simple, inexpensive, and eliminates errors. It is an object of the present invention to provide a serial data transfer device that prevents damage to equipment due to wiring, has a high noise margin, and can prevent erroneous transfers.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the serial data transfer device shown in FIG. 3, the transmitting device 1 is turned on by a control circuit 10 and a switching signal from the control circuit 10.

The device 2 on the receiving side includes a control circuit 12 and a detection circuit 13 that detects a signal transmitted from the transmitting side.

A power line AC is connected between these transmitting and receiving sides.
One signal line SL is connected to both.

FIG. 4 shows a specific circuit on the transmitting side and its signal waveform diagram, and FIG. 5 shows a specific circuit on the receiving side and its signal waveform diagram. First, the switching circuit 1 on the transmitting side in FIG.
1 is connected between one end of the power supply line L1 and one end of the signal line SL, and includes a diode DI whose anode is connected to the power supply line L1, and this diode D1.
The control circuit 1 is connected between the cathode of the resistor R, and the resistor R.
Switching signal from 0 turns on.

It has a switch SW that is controlled to be turned off.

In other words, on the transmitting side, the switch SW is turned on every cycle in synchronization with the AC signal a of the AC.

By turning it off, a signal is generated in which one cycle corresponds to one bit of data. For example, by synchronizing the switch SW with the AC signal a and turning it on when the transmitted data is 1" and off when it is 0, the signal line SL can be connected to the power supply AC. It is possible to take out synchronized 1 bit/cycle transmission data C. Note that the switch sW is actually a photocoupler, photothyristor, or the like.

On the other hand, the detection circuit 13 (rj:) on the receiving side is connected between the other end of the signal line SL and the other side L2 of the power supply line AC, as shown in FIG. , a resistor R2 and the input side (light emitting diode) of the photocoupler PC are connected between the other end of the signal line SL and the power supply line L2, and a diode D is connected in parallel to this human power side.
2 is the polarity shown, and the connected end is grounded via a resistor R3. Therefore, the received data d flows to the next side of the photocoupler PC in synchronization with the AC signal e, and the photocoupler PC
Serial data f can be taken out from the secondary side of the DC power supply vDD level. For example, as shown in FIG. 5(b), if there is received data d on the signal line SL, then I
Serial data f can be extracted as t l #, or o'' if there is none. Since the extracted serial data f is also a power-synchronized signal, serial/parallel data exchange is easily possible. be.

According to the above transfer device, it is possible to transfer data simply by providing another signal line SL outside the power supply line AC. Therefore, the signal line SL itself is strong against the original voltage level, and there is no fear of damage to the switching circuit 1 or the detection circuit 13 even if the signal line SL is connected to the power supply line AC due to incorrect wiring. Furthermore, since the signal voltage of the transmitted data is high, the noise margin is extremely high, and erroneous transfer can be avoided.

Further, it has advantages such as a very simple and inexpensive circuit configuration.

However, the above-mentioned apparatus has one device on the transmitting side and the other device on the receiving side, and has the disadvantage that data can only be transmitted in one direction. In other words, although it is possible to transmit a command from device 1 to device 2 and operate device 2 according to the instructions, it is possible to transmit an abnormality in device 2 to device 1, or to cause device 2 to operate according to the instructions.
There is a drawback that the request cannot be notified to device 1, and device 1 has to rely on a self-protection circuit that follows a certain sequence ◇ Therefore, next, it is possible to transfer serial data in both directions. The present invention will be described in detail. Figure 6 shows how one cycle of the power supply is divided into half cycles, and one cycle is divided from device 1 to device 2.
Figure 2 shows a serial data transfer device that uses the remaining half cycle to transfer data from device 2 to device 1. In this device, data is transmitted to both device 1 and device 2 in the same way as in the previous embodiment. Switching circuit 111.1 used for
12 and a detection circuit 131.13 used for data reception.
Q.

These switching circuits 111.11□ and detection circuit 1
30 and 132 each have a unidirectional transmission characteristic in the direction of the arrow shown in the figure. Therefore, the current flow from the power supply AC is the power supply line L.

When current flows from the source to the power line L2, data is sent from device 1 to device 2 along the path of power line L1 → switching circuit 111 → signal line SL → detection circuit 131 → power line L2 as shown by the solid arrow. , conversely, when the current flows from the t source line L2 to the power line L1, the power line L2 → switching circuit 1 as shown by the broken line arrow.
Data can be sent from the device 2 to the device 1 via the route 12→signal line SL→detection circuit 132→power line L1.

Here, the switching circuits 118 and 112 are turned on and off by a 1-bit/cycle switching signal synchronized with the power supply waveform output from the control circuit 10.12, as described above, and the forward half cycle is driven by 1 bit/cycle. The detection circuit 1 generates an AC level signal to be used as data.
31.132 is 111#, f when the current flows in the forward direction
It becomes °゛0'' when it does not.

As explained above, according to the present invention, one signal line is provided for transmitting and receiving data between two devices connected by a power line, and an AC power signal is transmitted by a 1-bit/cycle switching signal. The circuit configuration is such that the data signal obtained by turning on and off is transmitted through the signal line, and the receiving side detects the data from the signal line, so the circuit configuration is simple and inexpensive.
9- It is possible to provide a serial data transfer device that prevents damage to equipment due to incorrect wiring, has a high noise margin, and prevents erroneous transfer.

[Brief explanation of the drawing]

1 and 2 are circuit configuration diagrams of a conventional serial data transfer device, FIG. 3 is a circuit configuration diagram of a serial data transfer device according to an embodiment of the present invention, and FIGS. 4(a) and (b'
) shows a detailed circuit diagram of the transmitting side in Figure 3 and its operating signal waveform diagram, and Figures 5(a) and (b) show a detailed circuit diagram of the receiving side in Figure 3 and its operating signal waveform diagram. FIG. 6 is a circuit diagram of a serial data transfer device according to another embodiment of the present invention. 1... Sending side device, 2... Receiving side device, 10.
... Control circuit on the transmitting side, 11... Control circuit on the receiving side,
12.12. ．． 122...Switching circuit, 13゜131.132...Detection circuit, AC...' power supply, L
l. L2...Power line, SL-...Signal line, SW-
・Switch, D1#D2...Diode, PC...
Photocazola, R1-R3...Resistance. Applicant's agent Patent attorney Takehiko Suzue 10-

Claims (2)

[Claims] (1) In a serial data transfer device that transmits and receives serial data between two devices connected by an AC power line, one signal line provided between the devices and for transferring data; a control means configured on an AC power supply line to obtain a 1-bit/cycle switching signal synchronized with the AC power supply; and a control means connected between one end of the AC power supply line and one end of the signal line, the switching signal from the control means being connected between one end of the AC power supply line and one end of the signal line. a switching means configured between the other part of the signal line and the other part of the AC power supply line; 1. A serial data transfer device, comprising: a detection means for detecting transmission data sent through a signal line, and the serial data is transferred via the signal line. (2) The switching means and the detection means are respectively provided on the sides of the two devices, and the data transmitted from one device to the other and the data transmitted in the opposite direction correspond to half cycles of the AC power waveform in mutually opposite directions. 2. The serial data transfer device according to claim 1, wherein the serial data transfer device is formed using a %Ff signal so that data can be transferred alternately between both converters.