JPH0746811B2 - Signal transmission circuit - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal sending circuit for sending a data signal and an answer signal.

[Conventional technology]

In general, in a train in which a plurality of vehicles are connected, the state of each vehicle is controlled and monitored from the driver's cab or the conductor's cab. This signal is transmitted through a common pull-through that runs through all vehicles, but since multiple devices are connected to this pull-through,
It is necessary to regulate the transmission timing from each device to prevent signal collision. Therefore, it is conceivable that the AC power supply is used as the clock signal and each device is also used as the clock signal to perform accurate transmission timing control.

[Problems to be solved by the invention]

However, the signal transmission between the main engine provided in the driver's cab or the passenger compartment and each vehicle needs to be synchronized with the clock signal, but the internal operation of each device is not necessarily required by the common clock. Rather, asynchronous may improve economy and function, but because of the constraint that the main unit and slave units must be synchronized, the internal operation of the device was also synchronized with the clock signal, so there is freedom in operation. Was restricted.

Also, when trying to take an answerback, it is only necessary to perform the processing when no signal is sent, but for that purpose it is necessary to switch the signal line for data transmission and answerback transmission, and the reliability of the switching part Is a problem.

[Means for solving problems]

In order to solve such a problem, the present invention uses a photothyristor for transmitting a signal and changes the photothyristor that operates depending on whether the power source has a positive polarity or a negative polarity.

[Action]

The drive signal of the photothyristor is generated asynchronously, but the photothyristor is turned on / off in synchronization with the power supply waveform.
The signal supplied to the pull-through line is a signal synchronized with the power supply. Further, the data or answerback signal is used properly depending on the current direction of the same signal line.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of the present invention. In the figure, 1 is a main engine provided in a driver's cab or a conductor's cab,
Reference numeral 2 is a slave unit provided in each vehicle, U ₀ and V ₀ are power supply lead wires, and S is a signal lead wire. FIG. 1 shows a slave unit 1
Although only a stand is shown, in the actual device, a plurality of slave units 2 use common draw wires U ₀ , V ₀ , S, and draw wires U ₀ , V ₀ are shown in the figure. Power is supplied from the inverter.

The base unit 1 is composed of a transformer 10, diodes 11 and 12, resistors 13, data photo thyristors 14a and 14b, an answer-back photo thyristor 14c, and a control unit 15 for selecting these photo thyristors. The handset 2 has a resistance of 20a,
It is composed of 20b and Photocatsula 21a to 21d.

The operation of the device configured as described above is as follows.
A power supply (not shown) supplies the power supply line U ₀ with the power supply shown in FIG. 2A and the power supply line V ₀ with a power supply having a phase opposite thereto. Since the data shown in FIG. 2 (b) is sent to the signal lead-through line S, the control unit 15 controls the photothyristors 14a, 14a.
The signals shown in FIGS. 2 (c) and 2 (d) are supplied to b. Therefore, since photo-thyristor 14a is turned on at the timing of "I" of FIG. 2 (c), drawing-and line U ₀ is "1", when drawing-and line V ₀ is "0" photo-thyristor 14a, the diode
11, a current flows through the path of the resistor 20b, the photocoupler 21c, the transformer 10, and the photothyristor 14a. The direction of the current flowing through the line S at this time, that is, the direction from the master unit 1 to the slave unit 2 is defined as the forward direction. The polarity of the transformer 10 is determined so that the photothyristor 14b is turned off at this time.

Next, at the timing at which the polarities of the pull-through lines U ₀ , V ₀ are reversed, the photothyristor 14a is supplied with a voltage of opposite polarity on the thyristor side, so the photothyristor 14a is turned off. At this time, a voltage is induced in the transformer 10 such that the thyristor of the photothyristor 14b is in the forward direction. Then, since the control unit 15 supplies the signal shown by "b" in FIG. 2 (d) to the photothyristor 14b, the photothyristor 14b is turned on. Therefore, a current flows in the path of the photothyristor 14b, the diode 11, the resistor 20b, the photocatupler 21c, the photocatupler 21b, the resistor 20a, the transformer 10, and the photothyristor 14b, and the current in the positive direction flows in the signal line S.

Similarly, the photo thyristor 14a is turned on at the timings of “c” and “ho” in FIG. 2 (c), and at the timings of “ro”, “ni”, and “chi” in FIG. 2 (d). The photo thyristor 14b is turned on, and the signal line S is shown in FIG. 2 (b).
The data shown in (2) is sent out, and when the level is "1" in FIG. Therefore, various kinds of data can be transmitted depending on the combination of the presence or absence of the forward current sent to the pull-through line S.

When the data transmission is completed, the confirmation answer signal is transmitted and it is confirmed that the transmission is correctly performed.
Transmission reliability is improved. Therefore, when transmitting the answer-back signal, the control unit 15 sends out the signal shown in FIG. 2 (e) when the pull-through line U ₀ is "0" and the pull-through line V ₀ is "1". At this time, the forward voltage is supplied to the photothyristor 14c through the middle point of the transformer 10, the photocoupler 21dl, the resistor 20b, the resistor 13, the photothyristor 14c, the diode 12, and the right end path of the transformer 10.

Here, if the light emitting diode side of the photothyristor 14c is made to emit light when the signal shown in FIG. 2 (e) is supplied from the control unit 15, the photothyristor 14c is turned on and the slave unit is connected to the lead wire S. A current flows from 2 to the base unit 1. This direction is defined as the negative direction.

Here, for example, when the signal of FIG. 2 (e) is supplied,
When the timing at which the photothyristor 14c is turned on is examined, it is not turned on yet at time t1 because the reverse polarity voltage is supplied to the thyristor side of the photothyristor 14c. At time t2, the photothyristor 14
Since a positive voltage is supplied to the thyristor side of c, it turns on for the first time here. At time t3, the signal supplied from the control unit 15 disappears, but the photothyristor 14
Since the positive voltage is continuously supplied to the thyristor side of c, the thyristor side remains on. At time t4, the photothyristor 14c is supplied with a reverse polarity voltage on the thyristor side, and is turned off at this time. Thus, even if the phase of the signal sent from the control unit 15 is not synchronized with the power supply of FIG. 2 (a), the current flowing through the pull-through line S is As shown in FIG. 2 (b), the phase of the power source is completely the same. In addition, since the current flowing through the pull-through line S transmits data in the positive direction and the answer-back signal in the negative direction, two types of control and monitoring are performed with one signal line.

〔The invention's effect〕

As described above, since the present invention uses the photothyristor for signal control, even if the signal sent from the control unit does not match the phase of the AC power supply used as the clock signal of the system, The signal sent to the pull-through line can be matched with the phase of the power supply by the signal sent, and each device can be operated asynchronously, allowing a large degree of freedom in operation and economical efficiency. Get better. In addition, since the photothyristor is used differently depending on whether the AC power supply has a positive polarity or a negative polarity, the direction of the current flowing through the same pull-through line can be changed, and both the data and the answerback signal can be pulled in the same This has the effect of enabling transmission through a through wire.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a waveform chart of each part. 1 ... Parent machine, 2 ... Child machine, 10 ... Transformer, 14a-14c ...
… Photo thyristor, 15 …… Control part, 21a-21d …… Photo katsupura.

Claims (1)

[Claims] 1. A signal sending circuit for sending a data signal and an answer-back signal to a pull-through line connecting between a main machine and a slave unit by using an AC power supply, and supplying a forward current to the pull-through line when conducting. A photothyristor, a photothyristor that supplies a negative current to the pull-through line when conducting, and one photothyristor when the AC power supply has positive polarity and negative polarity are selected for data signal transmission, and the other when the AC power source has negative polarity. And a control unit for selecting the photo thyristor of claim 1 for transmitting the answer signal.