JPS5810992A - Bidirectional signal transmission circuit - Google Patents

Abstract

PURPOSE:To perform transmission with a single transmission line, through a simple constitution, by transmitting a signal having a level in response to the switching mode of a plurality of switches from a slave to a master device via a common transmission line and transmitting a signal having a predetermined level from the master to the slave device via the said transmission line. CONSTITUTION:A signal having a level in rsponse to the switching mode of a plurality of switches S1-S3 provided for a slave device 2 is transmitted to a master device 1 via a common transmission line 3. The master device 1 controls a load in response to a signal having the inputted level. The control state after the master device 1 makes a control is transmitted to the slave device 2 via the transmission line 3. That is, when the operation of the switches S1-S3 provided for the slave device 2 is not made and the load is controlled by operating a return signal detection circuit 38 of the master device 1, a return signal detection circuit 38 detects the state of control and generates a signal representing the control srate and returns the signal to the slave device 2 from the circuit 38 via an NPN transistor 40, a diode 41 and the transmission line 3. The signal is displayed on a display 39 of the slave device 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bidirectional transmission circuit that performs bidirectional signal transmission between a device used as a main controller and a prewinding device used as a terminal device.

In a conventional signal transmission circuit, a pre-winding circuit is equipped with a plurality of switches, and is configured to transmit a signal having a level corresponding to the switching mode of the switches to a parent device via a common transmission line. However, it has not been considered that a signal having a predetermined level can be transmitted from the device through the transmission line to perform communication.

The main object of the present invention is to solve the above-mentioned technical problems and provide a bidirectional transmission circuit with a reduced number of transmission lines.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

The drawing is an electrical circuit diagram of an embodiment of the present invention.

The device 1 and the pre-winding 2 are connected via a common transmission line 3, and a plurality of (three shown in the figure) switches 81, 82 . A good signal is transmitted from the pre-winding device 2 to the device 1 according to the switching mode of B3. (2) The main device 1 controls the load (not shown) 1 according to the signal inputted from the pre-winding device 2. In addition, the control state of the device 1 is controlled via the transmission line 3.
transmitted to. Such a pre-winding 2 is used, for example, to control a lighting fixture used as a load from a remote room.

In pre-winding 2, each switch sl, s2 . sa is commonly connected to a line 5 connected to the positive terminal of the DC power source 4. The switch 81 is, for example, a switch for turning on or off a lighting fixture, the switch B2 is a switch for increasing the light amount of the lighting fixture, and the switch s3 is, for example, a switch for decreasing the light 'Ikf of the lighting fixture. It's a switch.

The switch 81 is connected to the transmission line 3 via the transistor (yPH) and the diode 7 in the forward direction. Switch 82 is connected to transmission line 3 via NPN transistor 10 and forward diode 11. The switch B3 is connected to the transmission line 3 via an NPN transistor 14 and a forward diode 1st-.

NPN) The base of Ranjistaro is Zener diode Z
grounded through li, between the base of N2M transistor 6 and Zener diode Z1, and switch 81
A resistor 16 is connected between the transistors (NPN and NPN). MPN) The base of the transistor lO is grounded via the Zener diode 220NPN) A resistor 18 is connected between the base of the transistor lO and the Zener diode 22 and the switch 82 and IF) The base of the relay is grounded through the Zener diode 231. 1i
P1i) A resistor 2o is connected between the base of the plunger 14 and the Zener diode 23, and between the switch s3 and the transistor 14.

A detection circuit 60 is provided between transmission line 3 and line 5. In the detection circuit 6o, the line 5 is connected to the resistor 24.
and HP) J) are grounded via transistor 25. Transmission line 3 is also connected to NPIJ transistor 250 through resistor 26 and Zener diode Z4at-. Further, the signal at the connection point between the resistor 24 and the collector of the transistor 25 (IPli) is given to the display gain 39.

In the receiver I, the NPN) run raster 2 is connected through the transmission line 3, the resistor 28 and the Zener diode Zlai.
90 pace and connected to the base of resistor 31 (NPN) through resistor 3o and zener diode 22a'i, and connected to the base of resistor 31 and resistor 32 and zener diode Z3a.
NPM) is connected to the base of transistor 33 via NPM. Also, line 37 connected in the middle of line 5 is resistor 3.
4°35.36 are connected in series to NPN) transistors 29, 31, and 33, respectively. A signal generation circuit 61 is provided in this friendship l.

In the signal generation circuit 61C, the line 37 is connected to the return signal detection circuit 38.
The signal output from the NPN transistor is applied to the transmission line 3 via a transistor 40 and a forward diode 41. The base of the (NPN) transistor 40 is grounded via a Zener diode z4. A resistor 62 is connected between the collector and base of transistor /40.

In addition, each Zener, diode Zl-Z4, ZlaxZ
Zener voltage of 4a 'V,・Zll ~'V Z 4
, V Z 1a to VZ4a are VZI)VZla)VZ
2) Vzza)vza)vz3a)vza)vz4a The return signal generating circuit 38 is powered by power from the DC power supply 4 via the line 37. This return signal generation circuit 38 is connected to lines A and B, which will be described later.

RANGEMETA 40J
Derive C. Therefore, the emitter voltage output by the NUN transistor 40 when the Zener diode z4 breaks down is less than and approximately equal to the Zener voltage VZ4 of the Zener diode z4. The output from the emitter of transistor 40 is sent back to prewinding 2 via diode 41 and transmission line 3. Here V
Since Zla)'VZ2a)vZ3a)VZ4, the Zener diodes Zla, Z2a, and Z3a will not break down due to the signal from the diode 41.

The line A connected between the resistor 34 and the NPN) run raster 29 is connected to one input terminal of the NARD gate 43,46 and the NOT gate 45.
and NPN) The line B connected between the range metal 31 is connected to the other input terminal of the NAND gate 43 and one input ylAK of the NOR gate 44. Furthermore, the line C connected between the resistor 36 and the IFN transistor 33 is connected to one input terminal of the NOR gate 42 and the other input terminal of the NOR gate 44 . Output of NAND gate 43 DFiNOR gate 42
is input to the other input terminal of . The output EFi of NOR gate 44, the other input terminal of MAND gate 46 and WA
The output FF1N of the 0NOT gate 45, which is input to one input terminal of the ND gate 47, is input to the other input terminal of the ND gate 47. The output M of the ND gate 46 is NOT
Input to gate 48, output N of WAND gate 47 is NO? The signal is input to gate 49. The output G of the NOR gate 42 is a control signal indicating whether the switch 83 is pressed, and the output J of the NOT gate 48 is a control signal indicating whether the switch S2 is pressed.
The output of the gate 49 is a control signal indicating whether or not the switch Sl is pressed.

In such a bidirectional signal transmission circuit, the switch 81
When it is pressed and turned on, the NPII) transistor becomes conductive, and a voltage signal obtained by subtracting a small voltage drop between the base and emitter of the NPN transistor 6 and the diode 7 from the Zener voltage VZI is transmitted to the Zener diode via the transmission line 3. Acts on Zla, Z2a, and Z3a.

Here, each Zener diode Zla, 22a, Z3a breaks down and the NPN transistor 29.31.3
3 conducts. Therefore, lines A and B.

The signal derived to C becomes low level. Accordingly, the output of the WAND gate 43 becomes high level.
The output E of the 110R gate 44 becomes high level, and the NO
? The output of gate 45 becomes high level. Therefore NO
The output G of the R gate 42 becomes low level, and NAIJD
The output M of the gate 46 becomes high level, and the output N of the NAND gate 47 becomes low level. Therefore NO
The output J of the T gate 48 becomes a low level, and the output K of the NOT gate 49 becomes a high level.

In this way, the output K of the NOT gate 49 becomes high level, and the output G of the NOR gate 42 and the NO
The output J of the T gate 48 becomes low level, and the switch 8
A control signal indicating that 1 is conductive is output.

A voltage signal caused by pressing the switch s1 is transmitted to the NPIJ transistor 2 via the Zener diode 24a.
5 and thus the transistor 25
conducts. As a result, a low level signal is given to the display 39, and the display 39 performs a display operation in response to the low level signal. Switch 81 provided in pre-winding 2
- When the return signal detection circuit 38 of the electric appliance 1 is operated to control the load without performing the operation 83, the return signal detection circuit 38 detects the control state and sends a signal to the tIIIJ control state 1. Generates a return signal and detects it (b) Path 3
8 to NPN) is returned to the prewinding 2 via the transistor 40, the diode 41 and the transmission line 3.

The signal derived from the main unit 1 to the prewinding 2 is approximately VZ4, and also VZ4) and VZ4a. Therefore, Zener diode 24a breaks down and transistor 25 becomes conductive. The collector of the transistor 25 becomes low level, thereby causing the display 39 to perform a display operation.

Switch s1. $2,53t - Lines A, B, O and output when pressed, E, F, G, M.

The signals for N, J, are shown in the first column.

According to No. iH, switch day 2.83t - 4L each
When pressed to the pole, the output J becomes high level and the output G becomes high level.

As described above, according to the present invention, bidirectional signal transmission can be performed using a single transmission line with a simple configuration.

[Brief explanation of drawings]

The drawings are electrical circuit diagrams of one embodiment of the present invention. 1... Preparation device, 2... Pre-winding, 3... Transmission line, 7
, 11.15.41...Diode, 25.40...
・HPN transistor, 38...return signal detection circuit,
39...Display device, 60...Detection circuit, 61...Signal generation circuit, 62...Resistor-Zl, Zla, Z2,
22g, Z3*z3a, Z4. Z4a... - Zener diode agent Patent attorney - Kei Shirakyo

Claims (1)

[Claims] The pre-winding device includes a pre-winding device that generates signals having a plurality of levels through a common transmission line, and a device that discriminates the levels of the signals from the pre-winding device passing through the transmission line to control the load, and the pre-winding device includes:
A circuit is provided for level-discriminating and detecting a signal passing through the transmission line at a discrimination level lower than the above-mentioned level, and the equipment includes:
+4- The bidirectional signal transmission circuit according to claim 1, further comprising: a signal generation circuit that derives a signal having a level lower than the level 6 and higher than the discrimination level of the detection circuit to the transmission line.