JPH02214239A - Signal transmission circuit in transmission line - Google Patents

Abstract

PURPOSE:To decrease the kinds of oscillators and frequencies by using the oscillator so as to send and oscillating signal to a transmission line, while short- circuiting or non short-circuiting the transmission line in terms of AC to send a signal and receiving a transmission signal from a 2nd equipment with a 1st equipment. CONSTITUTION:An oscillator OSC sends an oscillation signal to a transmission line. A 2nd equipment sending a signal to a 1st equipment short-circuits the transmission line or non short-circuits in terms of AC by a transmission circuit section 2' in response to the transmission signal to be sent. The oscillated signal from the oscillator OSC to the transmission line is monitored to detect short- circuit or non short-circuit of the transmission line in terms of AC, then the 1st equipment allows to a reception circuit section 2'' to monitor the oscillation signal on the transmission line and to receive the transmission signal from the 2nd equipment. Thus, the transmission of the signal from the 2nd equipment such as a terminal equipment to the 1st equipment such as a receiver is realized effectively in terms of cost.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a transmission line such as an alarm facility, in which a plurality of second devices such as terminal equipment are connected to a first device such as a receiver. In particular, the present invention relates to a signal transmission circuit for transmitting signals from each second device to a first device.

[Prior Art] Generally, in a transmission line such as an alarm system consisting of a receiver and a plurality of terminal devices such as repeaters and sensors connected to the receiver, there is a transmission line between the receiver and each terminal device. There are two types, R type and P type, depending on the signal transmission form. In R-type alarm equipment, the receiver sequentially calls terminal devices such as repeaters and sensors connected to the receiver by polling based on the FSK transmission method or pulse transmission method, and each terminal device calls the terminal devices connected to the receiver by polling. In response, a status signal of the terminal device is sent back.

In addition, with P-type alarm equipment, polling operations are not performed from the receiver side, and when a terminal device such as a sensor or repeater detects an abnormality, it sends information such as analog smoke volume and alarm address to the receiver side. etc. are transmitted, and the determination is made by receiving and displaying them on the receiver side.

[Problems to be Solved by the Invention] When transmitting signals from the terminal device side to the receiver side in such a transmission line, the FSK method, pulse transmission method, etc. are used in the R type. Both have problems in terms of price. In addition, in the case of the P type, an individual address method is known in which a transmitter with an individual frequency is provided for each address on the terminal side, and the receiver side distinguishes the individual frequency of each terminal and displays only the address. However, this requires an oscillator to be provided on the terminal side, and each oscillation frequency must be individually assigned, which poses many problems in terms of cost and inventory management.

[Means for Solving the Problems] Therefore, an object of the present invention is to realize cost-effective transmission of a signal from a second device such as a terminal device to a first device such as a receiver. It is to do so.

Therefore, according to the present invention, in a transmission line in which a plurality of second devices are connected to a first device via a transmission line, an oscillator that outputs an oscillation signal to the transmission line; a transmission circuit unit provided in each of the second devices and configured to short-circuit or non-short-circuit the transmission line in response to a transmission signal to be transmitted from the second device to the first device; is provided in the first device, and monitors the oscillation signal from the oscillator onto the transmission line to detect an alternating current short circuit or non-short circuit in the transmission line, thereby detecting the transmission signal from the second device. A signal transmission circuit in a transmission line is provided, comprising: a reception circuit section for receiving data; and a signal transmission circuit for a transmission line.

[Effect] An oscillation signal is sent through the transmission line using an oscillator.

The second device that transmits data to the first device responds to the transmission signal to be transmitted, and causes the transmission circuit to short-circuit or non-short-circuit the transmission line in an alternating current manner.

Since an alternating current short circuit or non-short circuit in the transmission line can be detected by monitoring the oscillation signal from the oscillator onto the transmission line, the first device allows the receiving circuit to monitor the oscillation signal on the transmission line. Accordingly, it is possible to receive a transmission signal from the second device.

[Embodiment 1] Hereinafter, an embodiment of the present invention for transmitting a signal from a second device such as a terminal device in a signal transmission line to a first device such as a receiver will be described for the R type case. This will be explained using FIG. 1, FIGS. 2(a) and (b), and the case of P type will be explained using FIGS. 3, 4(&) and (b).

FIG. 1 shows an example of an R-type fire alarm equipment to which the present invention can be applied, and FIG. 2(a) shows an example of the reception mode in an R-type fire receiver. b) shows an example of a transmission mode from a terminal device such as an R-type fire detector or a repeater.

In the R type fire alarm equipment shown in FIG. 1, the main point of the present invention is the signal transmission from the terminal equipment to the fire receiver, and the signal transmission format such as polling from the fire receiver to the terminal equipment is the present invention. It is not the main focus of the invention, and any format may be adopted, but for example, it may be described in a patent application titled "Power transmission and transmitter" filed on the same day as the claimed invention. can. The patent application states that when supplying power and transmitting signals from the fire receiver to each terminal device, instead of providing separate power lines and signal lines, a pair of transmission lines is provided in response to the signal to be sent. The polarity of the power source is changed and connected to each terminal device, and each terminal device rectifies the power on the transmission line to use it as a power source for the terminal device, and also receives signals by detecting the polarity of the transmitted power source. is shown. In the following explanation using FIGS. 1 and 2, the discussion will proceed assuming that the signal transmission method such as polling from the fire receiver to the terminal device is that of the above patent application.

In the fire alarm equipment shown in Figure 1, a transmission line is installed between the fire receiver RE and which of the fire detectors DE or repeaters RP are connected to the fire receiver RE for the purpose of power supply and signal transmission. is installed. The signals sent from the fire receiver RE include digital drive command signals for the district bell connected to the repeater RP and various controllers when sending signals to the repeater RP. In addition, in the case of sending a signal to a fire detector DE such as a smoke detector, a data return command or a digital test signal to the smoke sensor of the smoke detector, etc. It is transmitted in a serial or serial transmission format.

Digital signals such as data return commands, drive commands, control commands, test commands, etc. that are processed by the microprocessor MPUI of the fire receiver RE and sent out are converted into serial form by the parallel/serial converter 1 and sent to the transmitting/receiving circuit. 2 input terminal T1. The transmitting/receiving circuit 2 connects the polar terminals and - of the terminal equipment power source E to the output terminals s and s2, respectively, or reverses the polarity and connects them to s2 and S, depending on the polarity of the signal applied to the input terminal T1. The signal thus applied from the parallel-to-serial converter 1 is transmitted onto the transmission line with the polarity of the power source E, which is also used as a power source for the terminal equipment.

The transmission signal is received by the transmission/reception circuit/power supply diagram B3 on the terminal device (fire detector DE or repeater RP) side, rectified there, and sent to the terminal power terminal PW as the power source to be used in the terminal device DE or RP. At the same time, the transmitted serial signal is extracted from the signal output terminal T of the transmitting/receiving circuit/power supply circuit 3 and is applied to the serial/parallel converter 4. The transmission signal in serial form applied to the serial-to-parallel converter 4 is converted there back into parallel form and, after signal processing in the microprocessor MPU2 of the fire detector DE or the repeater RP - as shown by way of example. drive the control command drive circuit 5, district bell drive circuit 6, test command drive circuit 7, etc.
Also, if it is a data return command by polling,
Sensor levels representing the amount of smoke are collected from the smoke sensor to send back data.

On the other hand, from the terminal/terminal device DE or RP to the fire receiver r
(When transmitting a signal to E, for example, when transmitting a sensor level signal indicating the amount of smoke detected by the smoke detector in response to a data return command from the fire receiver RF, According to the instructions of the microprocessor MPU2, the sensor level signals in the parallel form detected by the smoke detection section are converted into the serial form via the serial/parallel converter 4,
The signal is applied as a transmission signal to the terminal T3 of the transmitting/receiving circuit/power supply circuit 3, and is sent out from the transmitting/receiving circuit/power supply circuit 3 to the transmission line. In the fire receiver RE, the transmission signal sent out via the transmission line is received by the transmission/reception circuit 2 and given to the parallel/serial converter from the terminal T2, where it is converted back into parallel form and sent to the microprocessor. Signal processing is performed by MPU1.

After signal processing, if necessary, appropriate actions such as displaying on the display/operation section DP are taken.

An example of the transmitting/receiving circuit 2 shown in FIG. 1 is shown in FIG. 2(a).
, which includes a transmitting circuit section 2', capacitors C3 and C2 for DC blocking, reactance Le for AC blocking,
Le2, oscillator oSC with internal impedance R0
1 amplifier AMP, and a receiving circuit section 2'' including a frequency discrimination circuit DEM.An example of the transmitting/receiving circuit/power supply circuit 3 is shown in FIG. 2(b). 3°, the rectifier circuit section RF, - In addition to the AC component blocking glue actance Ln, the capacitor C3 and the fire receiver R
A transmitting circuit section 3'' is shown including a switch element SW that is turned on and off via a driver DR in response to a signal to be transmitted to E.

For example, when a signal such as a calling signal is given from the fire receiver RE to a terminal device as in a polling operation, other command signals such as a data return command are added to the address signal of the terminal device to be called. '1
", "0" in series form is applied to the transmitter circuit section 2' from the terminal T in FIG. It is rotated or reversed and connected to terminals s1 and s2, thereby supplying power and transmitting signals via the transmission line.

When the terminal equipment receives a signal transmitted via the transmission line, the transmitted signal is transmitted to the rectifier circuit section RF in FIG. 2(b).
It is rectified by the terminal PW and used as a power source for the terminal device, and the receiving circuit 3' detects the polarity of the signal sent out through the transmission line using, for example, a photocoupler having a light emitting diode and connects it to the terminal. A transmission signal including an address signal can be extracted from T. Terminal T4
If the address signal extracted from the address signal matches the address of the terminal device in question, and if the signal transmitted along with the address signal is a data return command, the microprocessor MPU2 responds by sending a message from the terminal T. Sensor levels, etc. will be returned.

When a call signal is sent from the fire receiver RE to the terminal device, the terminal T shown in FIG. 2(a).

The signal from the oscillator O8C disappears, and the transmitter circuit section 2° connects the power supply to the transmission line with constant polarity.
is activated, thereby entering a state of waiting for a return signal to be sent from the terminal equipment that has responded to the call signal from the fire receiver RE.

AC blocking actances Let and Le2 inserted in series in the transmitting circuit 2' shown in FIG. 2(a), and a second
Due to the presence of the AC blocking actance Ln inserted in series with the rectifier circuit section RF shown in Figure (b), the terminals of the transmission line! Ill and 82 are open or have very high impedance in terms of AC, and the oscillation output from the oscillator O8C is amplified by the amplifier AMP and sent to the frequency discrimination circuit DE.
For example, it is extracted from the terminal T via M as a "0" signal.

When a serial sensor level signal is applied from the terminal T in FIG. 2(b) in order to, for example, send back data in response to a call signal on the terminal equipment side, the signal's "0" and "1"
In response to this, the switch element SW is opened and closed via the driver DR. When the switch element SW closes in response to the input signal "1" to the terminal T, the terminals S, 32 of the transmission line become short-circuited or have an extremely low impedance value via the capacitor C3. The alternating current component of the oscillator O8C is isometrically short-circuited, which is detected by the frequency discrimination circuit DEM via the amplifier AMP and extracted as a "1" signal from the terminal T.

In this way, the amplifier AMP and frequency discrimination circuit DEM on the side of the fire receiver RE constantly monitor the AC component between the terminals 31 and S1 and detect the opening/closing of the switch element SW. The transmitted signal is effectively regenerated at the fire receiver RE side.

In addition, in the above, the impedances of capacitors C1, C2, and Cs at the oscillation frequency of oscillator ○SC are respectively Z
c, , Zc2, Zc, and the impedance of reactance Lel, Le2, Ln at the same frequency is Xe, ,
When Xen and Xn are used, it is necessary that the following formula % is satisfied.

FIG. 3 illustrates the present invention for transmitting signals from a second device, such as a terminal device, to a first device, such as a receiver.
Fig. 4(b) is a block circuit diagram showing an example of a case where the system is applied to a P-type fire alarm system; FIG. 2 is a circuit diagram for explaining an example of a transmission mode in a terminal device such as a receiver or a repeater.

The power supply E for terminal equipment in the fire receiver RE is always used to supply power to terminal equipment such as the fire detector DE and repeater RP via the energizing coil of the relay RL, the code receiving circuit 12, and the transmission line L. supply. Under normal conditions, the amount of current flowing to the terminal device is not large enough to energize relay RL, and therefore normally open contact r of relay RL is in an open state.

On the terminal equipment side in FIG. 3, when one threshold circuit determines that the sensor level signal detected by the smoke detection unit 17 exceeds a predetermined threshold to the abnormal side, The line alert signal is input to the terminal T7 of the transmitting circuit/power supply circuit 13, so that the transmitting circuit/power source circuit 13 causes the line alert signal to be sent out on the transmission line. Specifically, the transmission circuit/power supply circuit 13 responds to the line alarm signal applied to the terminal T, and outputs the signal from the terminal s1.32 of the transmission line.
By short-circuiting between the terminals and the terminals, sufficient current flows to energize the relay RL on the fire reception l1RE side.

On the fire receiver RE side, if the transmission signal sent out via the transmission line is based on the line alarm signal, a sufficient current is passed through the code reception circuit 12 to the coil of the relay RL. This energizes the relay RL, which closes the normally open contact r of the relay RL and turns on the lamp L.
P lights up or flashes, and the fire line is displayed in this way.

When it is determined that the sensor level signal has exceeded a predetermined threshold on the abnormal side and a line alarm signal is generated, the control circuit 15 in the terminal device DE or RP sends data and information regarding the status to the fire receiver RE. A sending operation is also performed. The control circuit 15 receives a sensor level signal representing, for example, the amount of smoke detected by the smoke detector 17 and converted into digital form by the analog-to-digital converter 18, and converts the signal from the analog-to-digital converter 18 into It is combined with the address signal of the terminal device set in the address setting section 16 and outputted to the parallel/serial converter 14, where it is converted into a serial form and then applied to the terminal T of the transmitting circuit/power supply circuit 13. The signal is then sent out from the transmitting circuit/power supply circuit 13 to the transmission line.

In the fire receiver RE, the transmission signal sent out via the transmission line is received by the code receiving circuit 12, and is applied to the terminal T of the code receiving circuit 12 to the serial/parallel converter 11, where it is converted into parallel The signal is converted back into the form and processed by the microprocessor MPU 1. After signal processing,
The address is displayed on the display section DP, and from this it is possible to know which terminal device the line alarm signal was generated from, and appropriate actions such as displaying the smoke concentration on the display section DP2 can be taken. .

A circuit example of the code receiving circuit 12 shown in FIG. 3 is shown in FIG.
As shown in FIG. 2(a), it includes a DC blocking capacitor C1, an oscillator O8C having an internal impedance R0, an amplifier AMP, and a frequency discrimination circuit DEM, as shown in FIG. Furthermore, an AC block actance L'' for preventing AC signals transmitted through the transmission line from escaping via relay RL and power supply E is also shown.

In addition, an example of the circuit of the transmitting circuit/power supply circuit 13 is shown in FIG. 4(b).
2(b), comprising a capacitor C5 and a switching element SW1 which is turned on and off via a driver DR by the signal to be sent to the fire receiver RE. A transmitting circuit section 1 similar to the transmitting circuit section 3''
3°, and an alarm transmitting circuit section 13'' comprising a Zener diode ZN and a switch element SW2 turned on via a driver DR2 by a line alarm signal. The Zener diode ZN is to guarantee the remaining voltage of the internal power supply when the switch element SW2 is turned on.
You can use a resistor instead of a Zener diode.
In order to prevent the transmission signal to be sent from the transmission circuit section 13° to the transmission line from escaping via the alarm transmission circuit 13'', there is a connection between the transmission circuit section 13' and the alarm transmission circuit section 13''. is shown connected with an AC blocking actance Ln similar to that shown in FIG. 2(b).

When a line alarm signal is input to the terminal Tt, the switch element SW2 is closed via the driver DR2, and a direct current is established between the terminals 31 and 32 of the transmission line via the Zener diode ZN. This causes a short circuit, which energizes the relay RL shown in FIGS. 3 and 4(a) and closes the contact r, thereby indicating a fire line.

After the line alarm signal is generated, data information etc. are sent from the terminal equipment to the fire receiver RE using the transmission signal input from the terminal T, in the same way as explained in FIGS. 2(a) and (b). This is done by opening and closing the switch element SWl in response. As a result, on the fire receiver RE side, the oscillator O8C
Since the alternating current component output from the terminal T is sometimes short-circuited or not, this is detected and a series signal is taken out from the terminal T.

[Effects of the Invention] As described above, according to the present invention, in either case of R type or P type, an oscillator causes an oscillation signal to flow through the transmission line, and the second device responds to the transmission signal, that is, transmits the signal. The signal is transmitted by making the transmission line short-circuited or non-short-circuited in accordance with the code to be transmitted, and the first device monitors the transmission line for short-circuiting or non-short-circuiting, thereby transmitting the signal from the second device. Since the transmitted signal is received, only one oscillator and one frequency are used.
This has the effect of being very advantageous in terms of price and inventory management.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing an embodiment in which the present invention is applied to an R-type fire alarm system, and FIGS. 2(a) and 2(b) are the fire receiver side of FIG. 1, respectively. FIG. 3 is a circuit diagram showing a transmitting/receiving circuit and a transmitting/receiving circuit/power supply circuit on the terminal equipment side. FIG. ) and the fourth
FIG. 3B is a circuit diagram showing a code receiving circuit on the fire receiver side and a transmitting circuit/power supply circuit on the terminal equipment side, respectively, in FIG. 3. In the figure, RE is a fire receiver, DE is a fire detector, and R
P is a repeater, L is a transmission line, E is a power supply for terminal equipment, 2 is a transmitting/receiving circuit, 2° is a transmitting circuit, 2" is a receiving circuit, oS
C is an oscillator, C, , C, is a DC blocking capacitor, A
MP is an amplifier, DEM is a frequency discrimination circuit, 3 is a transmitting/receiving circuit and power supply circuit, sw, sw, SW2 is a switch element,
C5 is a capacitor, Le+, Le, Ln, Lr are capacitors for blocking AC components, 12 is a code receiving circuit, RL is a relay, LP is a lamp for indicating a fire line, 13 is a transmitting circuit and power supply circuit, ZN is a zener・Diode, 15 is a control circuit, 16 is an address setting section, 17 is a smoke detection section, and 19 is a threshold circuit. Peng 2 figure (a) 2“

Claims (1)

[Claims] A transmission line in which a plurality of second devices are connected to a first device via a transmission line, comprising: an oscillator that outputs an oscillation signal to the transmission line; and the second device. a transmitting circuit unit provided in each of the above-mentioned devices and configured to short-circuit or non-short-circuit the transmission line in response to a transmission signal to be transmitted from the second device to the first device; A receiver provided in the device and configured to receive the transmission signal from the second device by monitoring an oscillation signal from the oscillator onto the transmission line and detecting an alternating current short circuit or non-short circuit in the transmission line. A signal transmission circuit in a transmission line, comprising a circuit section;