JPS59200532A - Monitoring and control system of terminal equipment - Google Patents

Abstract

PURPOSE:To perform monitoring and control easily without increasing the number of couples of transmission lines by switching the monitor part and control part of a monitor station upon occasion, and connecting power sources for them so that their polarities are opposite between the monitor part and control part. CONSTITUTION:A changeover switch 13 is connected normally to the monitor part side including a power source 41 and a current detecting circuit 5 at the monitor station 1, and a monitoring voltage is applied from the power source 41 to a terminal equipment 2 through a monitor control line 3. The control relay 9 of the equipment 2 is disconnected from the circuit by a diode D14 and does not operate, a resistance sending circuit is formed of diodes D151 and D152 to vary a circuit current by opening and closing contacts 71 and 72, and the monitor station 1 detects that by the circuit 5 to obtain monitor information on the terminal equipment. When the switch 13 is placed on the lower side corresponding to the control part side and a push button 6 is depressed, the D14 conducts by the control voltage of a power source 42 and the control relay 9 is energized to perform control, turning off the diodes D151 and D152.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a system for monitoring and controlling subscriber terminal equipment connected to a unidirectional wired transmission line.

[Description of prior art]

Regarding the monitoring and control of subscriber terminal equipment, a monitoring and control method that is as simple as possible is required due to the large number of objects to be monitored and the relative weight of the system as a whole.

Examples of conventional methods are shown in FIGS. 1 and 2.

In the system shown in FIG.
and a control line 32, and the monitoring station 1 is provided with a monitoring section including a power source 41 and a current detection circuit 5, and a control section including a power source 42 and a push button switch 6. The terminal device 2 also includes contacts 71 and 72 that open and close in response to faults, and a resistor 81 through which current flows in response to the opening and closing of these contacts 71 and 72.
．． A resistance sending circuit including 82 and a control relay 9 for controlling the operation of this terminal device 2 are provided. The terminal equipment 2 is monitored by determining the resistance value change of the resistance sending circuit by the current detection circuit 5 via the monitoring line 31, and the terminal equipment 2 is controlled by using the control relay 9, which is separately sealed. control line 3
This is done by remote control via 2.

In the system shown in FIG. 2, a monitoring station 1 and a terminal device 2 are connected by a pair of monitoring control lines 3, and the monitoring station 1 has signal generators 103 and 104 of frequencies f3 and f4 and signal receivers of frequencies f1 and f2. A circuit I11.112 is provided, and the terminal device 2 is also provided with a signal generator 101.102 of frequencies f, , f2 and a signal receiving circuit 113, 114 of frequencies f3, f4. The monitoring and control of the terminal equipment 2 is carried out by assigning signals of respective frequencies to the monitoring and controlling devices, transmitting and receiving these signals via the same pair of monitoring and control lines 3, and determining the level of the received signals. To do this.

Although the method shown in FIG. 1 is simpler than the method shown in FIG. 2, it is difficult to apply to subscriber terminal transmission lines where the number of logarithms that can be used is limited.

Furthermore, the method shown in FIG. 2, which uses a small number of logarithms, has the disadvantage that the circuit becomes large-scale.

[Purpose of the invention]

It is an object of the present invention to provide a terminal device monitoring/control method that is particularly effective when applied to such transmission lines with restrictions on the logarithms used, and allows easy monitoring and control without increasing the logarithms of the transmission lines. With the goal.

[Features of the invention]

The configuration of the present invention is such that the monitoring station has a monitoring section consisting of a power supply and a current detection circuit, and a control section consisting of a switch and a power supply, and the monitoring section and the control section are switched as necessary to connect the monitoring control line. Configure it so that you can connect to it. At this time, the polarities of the power source for the monitoring section and the power source for the control section are made to be reversed. On the terminal device side, a relay and a first diode connected in series are connected between a pair of monitoring control lines, and at the subsequent stage there is a contact that opens and closes depending on the monitored item and a current that flows depending on the opening and closing of this contact. A resistor delivery circuit consisting of a network of resistors that change state is connected, and a second diode supplying current to the resistor delivery circuit is connected in opposite polarity to the first diode.

[Explanation based on examples]

Embodiments of the present invention will be described below based on the drawings.

FIG. 3 is a block diagram showing an embodiment of an apparatus according to the present invention.

In FIG. 3, a monitoring station 1 and a terminal device 2 are connected by l pairs of monitoring control lines 3. In FIG.

The monitoring station 1 includes a monitoring section consisting of a power supply 41 and a current detection circuit 5, a control section consisting of a power supply 42 and a pushbutton switch 6, and a changeover switch 13. The monitoring unit is a circuit that applies a monitoring voltage to the monitoring control line 3 via the changeover switch 13 from the power supply 41, and the current flowing through the monitoring control line 3 is detected by the current detection circuit 5.

Further, the control section is a circuit that applies a control voltage having a polarity opposite to the above-mentioned monitoring voltage to the monitoring control line 3 from the power source 41 via the changeover switch 13.

The terminal H2 includes a control relay 9, contacts 71 and 72 that open and close according to the monitoring item, and a resistor 81 according to the monitoring item.
．． 82 and diodes 14.151.152. Examples of the items to be monitored include the importance of power supply and the reception level of pilot signals when pilot monitoring is performed. Contact 7172, resistor 81.82, and diodes 15s and 152 form a resistance sending circuit, and the current flowing through this resistance sending circuit changes depending on the open/closed state of contact 71.72. Diode 14 is connected in series to control relay 9 so as to be biased in the forward direction by a control voltage from power supply 42 . Further, diodes 151 and 152 are connected in series to contacts 71 and 72 so as to be forward biased by a monitoring voltage from power supply 41.

Next, the operation of the above embodiment device will be explained.

In the monitoring station 1, the changeover switch 13 is normally switched to the upper side of the figure so as to connect the monitoring section to the monitoring control line 3, and a monitoring voltage from the power supply 41 is applied to the monitoring control line 3.

In this case, in the terminal device 2, the control relay 9 is cut off from the circuit by the diode 14, and therefore does not operate. On the other hand, the resistance sending circuit has its diodes 15t, 15
2 becomes a forward bias, a circuit is formed, and the circuit current changes by opening and closing contacts 71 and 72 according to the monitoring item. The monitoring station 1 detects this current change through the monitoring control line 3 with the current detection circuit 5, and thereby can detect monitoring information of the terminal equipment.

Next, in order to control the terminal device 2, the changeover switch 13
is switched to the control unit side, that is, to the lower side of the figure, and the control voltage from the power supply 42 is applied to the supervisory control line 3. In this case, contrary to the above, diode 14 becomes conductive and diode 1
5z and 152 are cut off, the control relay 9 is operated and control is performed.

In the above embodiment, the diodes 15+ and 152 were provided corresponding to the contacts 71 and 72, respectively, but the present invention is not limited to this. For example, one diode may be connected in series with the resistor 82. It is clear that a configuration such as that shown in FIG. Furthermore, as for the configuration of the monitoring station 1, it is of course possible to use a single power source for applying voltage to the monitoring control line 3, and to apply a voltage by reversing the polarity using a changeover switch. Furthermore, the present invention may also be implemented by using a constant current source instead of the power supply 41 and using a voltage detection circuit instead of the current detection circuit 5 to flow a constant current through the line 3 and monitor voltage changes. The effect remains the same.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to easily monitor and control a terminal device by switching the polarity using a pair of monitoring and control lines.

Therefore, the present invention is particularly useful when applied to cases where there are restrictions on the logarithm of the transmission line. Furthermore, the configuration of the monitoring station and terminal equipment is extremely simple, which helps reduce the size and cost of the device.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are block configuration diagrams showing an example of a conventional system. FIG. 3 is a block diagram of a device according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Monitoring station, 2... Terminal equipment, 3... Monitoring control line, 4□, 42... Power supply, 5... Current detection circuit, 7
1.72...Contact, 81.82...Resistor, 9...
・Control relay, 13... Selector switch, 14.15
z, 152...diode.

Claims (1)

[Claims] (1) In a system comprising a monitoring station and a terminal device connected to the monitoring station by a pair of lines, and in which the operation of the terminal device is monitored and controlled from the monitoring station, the monitoring station has the following: a monitoring unit that is connected to the pair of lines and applies a monitoring voltage between the lines, and detects a change in the state of the terminal equipment based on a change in the voltage or current of the line; The terminal equipment includes a control unit that applies a control voltage having a polarity opposite to the monitoring voltage between the lines, and a switching unit that switches connection of the monitoring unit to the control unit to the line, a control relay that controls the operation of the terminal device; a first rectifier circuit that is connected between the lines so as to be in the forward direction with respect to the control voltage and supplies an operating current to the control relay; a resistance sending circuit including a contact circuit that opens and closes depending on the monitoring item and a resistance circuit whose current value changes depending on the open/close state of the contact circuit; A method for monitoring and controlling terminal equipment, comprising: a second rectifier circuit connected between the circuits and supplying current to the resistor sending circuit.