JPS6286929A - Input circuit for receiving set in communication equipment using commercial power source line as communication line - Google Patents

Abstract

PURPOSE:To eliminate necessity of judging polarity and prevent occurrence of troubles such as impossibleness of communication etc. even if polarity is reversed by working of distribution lines after installation, by constituting the titled circuit so as to connect selectively the one side input terminal connected to a non-active line in a reception control part with the active line through a contact part of a relay. CONSTITUTION:When a pair of input terminals 4a, 4b to be connected to a distribution line 5 are connected, that is, when an inactive line 5a is connected to the input terminal 4a, and an active line 5b is connected to the input terminal 4b, a photocoupler is not made on, and accordingly, the input terminal 11a of a relay driving circuit 11 remains at high potential ('1') and the state (non-operation) of a relay 10 does not change. Accordingly, an input terminal 7a of an reception control section 7 is connected to the inactive line 5a through a capacitor 13, a contact 10a (k2) and the input terminal 4a, and transmission and reception between the transmitter 2 become possible. When the input terminal 4a is connected to the active line 5b, and the input terminal 4b is connected to the inactive line 5a, AC voltage (100V) is applied between the input terminal 4a and ground, and thereby, the photo-coupler 9 is made on.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an input circuit of a receiver in a communication device using a commercial power line.

"Prior Art" Communication devices that use commercial power lines as communication lines are known. There are two types of communication lines, depending on how they are used: the line-to-line method and the ground-return method. The line-to-line method injects the transmission signal between two distribution wires (power supply lines), and the transmission signal may be affected by the condition of the load connected to the power supply line, but polarity must be considered when connecting. There is no. The ground return method injects the transmitted signal into the inactive line of the power line, and the transmitted signal is less affected by the state of the load connected to the power line. It took a lot of effort to determine whether the line was a non-active line or not. Further, after installation, there is a risk that the polarity of the connection to the power outlet may be reversed due to construction work on the power distribution line, and in that case, there is a problem in that it may be necessary to change the connection.

FIG. 2 is a route connection diagram illustrating the principle of the return route system.

1 is a power transformer, 5 is a distribution line; for example, in the case of a single-phase two-wire distribution system, a non-active line 5 connected to a grounding line 6;
Either line a or the other line is used as a commercial power line, and these two lines are connected to an outlet. 2
3 is a transmitter, 3 is an injection transformer for injecting the output signal of the transmitter 2 into a non-active line, and 4 is a receiver. That is,
The transmitter 2 is connected to the loop formed between the non-active wire 5a and the ground.
and the receiver 4 to transmit signals. Therefore, one input terminal of the receiver 4 must be connected to the ground side, and the other input terminal must be connected to the inactive line 5a via an outlet or the like. However, this connection has the problems mentioned above.

"Problems to be Solved by the Invention" The present invention does not require polarity discrimination when connecting a receiver, and also eliminates the need to change the connection even if the polarity of the connection to the outlet is reversed due to work on the distribution line, etc. It is intended to obtain an input circuit for a receiver that does not have a receiver input circuit.

``Means for Solving the Problems'' Therefore, the present invention provides an input circuit for a receiver that receives a signal from a transmitter injected into a non-active line of a commercial power line.
A relay that has a pair of input terminals connected between commercial power lines, a contact that is connected to the input terminals and switches between them, and is turned ON by the voltage between the switch-connected input terminals and ground. , and a photocoupler connected to turn off, the relay is driven depending on the state of the photocoupler, and one input terminal of the reception control unit is connected to the inactive line via the contact. It is.

"Function" One input terminal connected to the inactive line of the reception control section is
Since the structure is configured so that it is selectively connected to the above-mentioned inactive line through the relay contacts, there is no need to determine the polarity when installing the receiver, and the polarity can be reversed due to distribution line construction etc. after installation. Even if there is a problem, the connection is automatically switched and there is no inconvenience such as communication being disabled.

Embodiment FIG. 1 is a block diagram illustrating an input circuit of a receiver according to the present invention. Components that are the same as those in FIG. 2 are given the same reference numerals for easy understanding. Reference numeral 7 denotes a reception control section, which is configured to receive the transmission signal from the transmitter 2 and send a response signal to the transmitter 2 as necessary, and the circuit configuration is the same as before. ? a and 7b are its input terminals, respectively. 9 is a photocoupler, 8 is a photocoupler protection diode, 10
is a relay, and 10a is its contact. Reference numeral 11 denotes a relay drive circuit, which is configured to operate when a low potential (rob) is applied to its input terminal 11a, invert the relay 10 (operate or restore) each time, and maintain that state.

That is, when "O" is applied to the input terminal 10a while the relay 10 is in the non-operating state, the relay drive circuit 11 brings the relay 10 into the operating state and maintains it. Next, a circuit is configured to restore the relay 10 when "0" is applied to the input terminal 10a, and can be configured by, for example, a voltage detection circuit, a flip-flop circuit, or the like. 10a is a contact point of the relay 10, and a pair of input terminals 4a,
4b is connected to the input terminal 7a of the reception control section 70. The above pair of input terminals 4a
, 4b are connected between two lines of the power distribution line 5, that is, the inactive line 5a and the active line 5b.

On the other hand, the input terminal 7b of the reception control section 70 is grounded as in the conventional case. 12 is a dielectric strength capacitor, 13 is a coupling capacitor, and 14.15 is a circuit protection resistor.

Next, the operation will be explained.

A pair of input terminals 4 connected to a power distribution line 5 (commercial power line)
a, 4b are connected with those shown in FIG.
When b is connected, the photocoupler 9 is not turned on, and the input terminal 11a of the relay drive circuit 11 remains at a high potential (rxJ), so the state (non-operation) of the relay 10 does not change. Therefore, one input terminal 7a of the reception control section 7 is connected to the inactive line 5a via the capacitor 13 and the contact toa (kz) input terminal 4a, so that signals can be transmitted and received with the transmitter 2. Then, after that, the distribution line 5
If the polarity is reversed due to construction work etc., and the input terminal 4a is connected to the active wire 5b and the input terminal 4b is connected to the inactive wire 5a, an AC voltage (1oo
Since input terminal 4a and contact 10a (kz
), the resistor 14, the capacitor 12, the photocoupler 9, and the ground intermittently pass current, and the photocoupler 9 is turned on accordingly. Therefore, since "0" is given to the input terminal 11a of the relay drive circuit 11, the relay drive circuit 11 operates (by detecting the above "0" multiple times, malfunctions due to noise etc. can be prevented. (In this case, a counter circuit or the like may be provided in the input circuit, but the circuit itself is common and will not be described in detail.)
Then, the relay 10 is reversed from its previous state (non-operating),
i.e. make it work and hold it. This switches the contact 10a. Therefore, the reception control unit 70 input terminal 7a
is again connected to the inactive line 5a, and signals can be transmitted and received with the transmitter 2.゛In the above explanation, the case where the pair of input terminals 4a and 4b are connected to the distribution line 5 and then the polarity becomes reversed is explained, but even if the pair of input terminals 4a and 4b are connected to the reverse polarity from the beginning, the relay drive circuit 11 will be Work,
It is easy to understand that the input terminal 7a is connected to the inactive line i5a.

``Effects of the Invention'' As explained above, according to the present invention, when installing a receiver, it is not necessary to determine the polarity of the power distribution line (commercial power line) that serves as a communication line, and the polarity cannot be determined due to construction of the power distribution line after installation. Since it is automatically connected to the positive polarity even when the polarity is reversed, the trouble of changing the connection can be saved, and the practical effect is remarkable.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating an input circuit of a receiver according to the present invention, and FIG. 2 is a line connection diagram illustrating the principle of a return-to-ground method for a communication device using a commercial power line as a communication line. 1... Power transformer, 2... Transmitter, 3... Injection transformer, 4... Receiver, 5... Distribution line, 7...
Reception control unit, 9... photocoupler, 10... relay, 11... relay drive circuit.

Claims (1)

[Claims] In an input circuit of a receiver that receives a signal from a transmitter injected into an inactive line of a commercial power line, a pair of input terminals are connected between the commercial power lines, and one of the input terminals is connected to the input terminal. a relay having a contact that switches to one side and connects the other;
O due to the voltage between the input terminal connected above and ground
Equipped with a photocoupler connected to turn N and OFF,
A commercial power line is used as a communication line, characterized in that the relay is driven depending on the state of the photocoupler, and one input terminal of the reception control unit is connected to an inactive line via the contact point. A receiver input circuit in a communication device.