JPH03178255A - Network controller - Google Patents

Abstract

PURPOSE:To reduce the electric current consumption and to allow a telephone set to attain operation with high reliability by disconnecting a voltage detection means from an operating power supply in the case other than the detection of the voltage of the operating power supply. CONSTITUTION:A voltage detection means 41 is connected to an operating power supply only before a switch means 9 disconnecting a telephone set 5 from a telephone line is operated and the same current as the current flowing to the switch means 9 is supplied from the operating power supply to make the load condition the same. In this case, a voltage VDD of the operating power supply is detected and in other cases, the voltage detection means 41 is disconnected from the operating power supply to avoid power consumption. Thus, the voltage of the operating power supply is detected to reduce current consumption and sure operation is attained with high reliability.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is a device that is connected to a telephone line in parallel with a telephone, and transmits various data such as usage data of electricity, gas, water, etc. The present invention relates to a network control device that controls transmission to a center device via a line.

(Prior art) In automatic meter reading systems, etc., in which data on usage of electricity, gas, water, etc., read at a terminal, is transmitted to a central device, which is a central management device, various information and data at the terminal are transmitted to the central device. uses telephone lines to do so.

More specifically, a network control device is connected in parallel with a telephone connected to a telephone line, and the network-side tM device calls the center device via the telephone line to transmit various data to the center device.

When a network control device is connected to a telephone line in parallel with a telephone, various signals from the network control device are supplied to the telephone, and the network control device transmits data in order to prevent the telephone from malfunctioning. If so, the telephone is controlled to be disconnected from the fairy tale line. Specifically, when a network control device performs a dialing operation to call a center device in a series of operations for data transmission, the bells of telephones connected in parallel to the telephone line momentarily ring 111.
), the telephone may malfunction due to the data communication signal being transmitted, or a facsimile machine may be connected to the telephone. In order to prevent undesirable operation such as malfunction, Il! While the J control device is transmitting data, it is necessary to disconnect the telephone from the telephone line.

Relays are generally used to disconnect such telephones from the telephone line, but there are two types of relays: ordinary relays that operate only while current is flowing through the coil, and ordinary relays that operate only while current is flowing through the coil. There is also a holding type relay, or latching relay, which maintains the operating state, that is, the on state or the off state, by a holding function.9 Normal relays operate only while current is flowing through the coil, so they are not susceptible to disturbances such as noise. Although the influence of malfunction caused by this is small, it has the disadvantage that current consumption is large because it is necessary to constantly flow current through the coil during operation. In addition, latching relays have a low current consumption because they mechanically perform the holding operation, but if the line disconnection state is maintained and the state cannot be recovered, all the parallel-connected telephones will be disconnected. ! ! It may become unusable.

In addition, as mentioned above, the network control devices used in automatic meter reading systems that collect usage data on electricity, gas, water, etc. are generally installed outdoors, so they rely on batteries as their operating power source. used. Therefore, in order to prevent battery consumption, the network control device preferably uses a latching relay that is mechanically held and consumes less current than a normal relay that consumes a large amount of current.

As mentioned above, the state in which the latching relay cannot be restored while it is held is generally when the battery used as the operating power source is exhausted and cannot supply enough current to the latching relay to completely restore the latching relay. However, in order to prevent this situation, a method has been proposed that detects the battery voltage and transmits data only within a range that can sufficiently drive the latching relay. As mentioned above, the voltage of the battery that is the operating power source is detected,
The conventional method of transmitting data only within a range that can sufficiently drive the relay has the problem of increased current consumption because the circuit that detects the battery voltage is constantly operating.

The present invention has been made in view of the above, and its purpose is to detect the voltage of the source that operates only when necessary, reduce current consumption, and provide network control that operates accurately with high reliability. The goal is to provide equipment.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, a network control device of the present invention provides a network control device that is connected to a telephone line in parallel with a telephone set and that controls data transmission through the telephone line. The control device includes a switch means that operates to disconnect the telephone from the telephone line during data transmission, a voltage detection means that detects a voltage of an operating power source before operating the switch means, and the voltage detection means includes: Voltage detection a only when detecting the voltage of the operating power supply
) a power supply disconnecting means for connecting the means to an operating power source and at other times disconnecting the voltage detecting means from the operating power source so that the voltage detecting means does not consume power; and when the voltage detecting means detects the voltage of the operating power source, the switching means The gist of the present invention is to have means for making the load conditions the same by causing a current of the same value as the current flowing through the operating power source to flow from the operating power source.

(Function) In the network control device of the present invention, the voltage detection means is connected to the operating power source only before operating the switch means for disconnecting the telephone from the telephone line, and a current of the same value as the current flowing through the switch means is operated (1 'The voltage of the operating power source is detected under the same load condition with the flow j- from the heavy source, and at other times the voltage detection means is separated from the operating power source to avoid consuming power.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a circuit diagram of a network control device according to an embodiment of the present invention. The network control device shown in the figure has a terminal LL, as shown as block 3 in FIG.

Connected from L2 to the telephone switching network 2 via the telephone line 7,
The telephone exchange network 2 is further connected to a center device 1 such as an automatic meter reading system. In addition, the network control device 3
For example, it is connected to a terminal device 4 constituting a meter for reading electricity, gas, water, etc., and controls data transmission between the terminal device 4 and the center device 1.

Furthermore, the network control device 3 has a telephone 5 from the terminals Tl and T2.
This telephone 5 is connected in parallel to the network control device 3 via the break contact 9b of a latching relay, which is a holding type switch, and the telephone 5 is connected in parallel to the network control device 3. If not, phone 5
If a telephone call can be made via the telephone line 7, and if the network control device 3 is controlling data transmission between the terminal device 4 and the center device 1, the break contact 9b opens and the telephone 5 cannot make phone calls.

In the network control device 3, as shown in FIG. 1, terminals Ll and L2 to which the telephone line 7 is connected are connected to an internal circuit (not shown) of the main network control device 3, and one terminal L1 is connected to the connected to terminal T1 and the other terminal L2
is connected to terminal T2 via break contact 9b of latching relay 9, thereby connecting telephone 5 connected to terminals TI and T2 to telephone port a7 via terminals Ll and L2.

In addition to the break contact 9b, the latching relay 9 includes a recovery reset coil 9R and a disconnection set coil 9.
It has S. The recovery reset coil 9R is connected to the collector of the recovery transistor 25, and the base of the recovery transistor 25 is connected to the reset output terminal R3T of the CPU 15 via a resistor 2L. Further, the disconnection set coil 9S is connected to the collector of the disconnection transistor 27, and the base of the disconnection transistor 27 is connected to the set output terminal SET of the CPUI 5 via the resistor 23. When a set signal is output from the set output terminal SET of the CPU 15, this signal causes the latching relay 9 to pass through the disconnection transistor 27.
The disconnection set coil 9S is driven, thereby operating the latching relay 9, opening its break contact 9b, disconnecting the telephone 5 from the telephone port i7, and the latching relay 9 no longer receives the set signal B from the CPU 15. After that, the operating state, that is, the break contact 9b remains open. In addition, in such an operation holding state, when a reset signal is output from the reset output terminal R3T of the CPUI 5, the recovery reset coil 9R of the latching relay 9 is driven by this signal via the recovery transistor 25. The operation holding state of the latching relay 9 is released, its break contact 9b is closed, and the telephone 5 is connected to the telephone line 7, and even after the reset signal from the CPU 5 disappears, the latching relay 9 continues to operate. The break contact 9b remains closed.

The CPU 5 controls the overall operation of the main network control device, and is operated by a battery 43 connected between its power terminals VDD and V38. The battery 43 is also supplied to the latching relay 9 and other circuits of the main network control device in addition to the CPU 15, thereby operating the main network control device. Note that the CPtJ 45 normally stops operating in order to reduce consumption of the battery 43, and the terminal call request signal from the terminal device 4 is
It starts operating only when it is supplied to the NT input terminal, and stops operating again when the uncalled communication process is finished.

The base of an auxiliary power supply disconnection transistor 31 is connected to the battery scanning terminal BS of the CPU 15 via a resistor 33, and the collector of this transistor 31 is connected to the base of a power supply disconnection main transistor 37 via a resistor 35. There is. The collector of the main transistor 37 for disconnecting the power supply is connected to the terminal (2) of the voltage detection circuit 41, and the emitter thereof is connected to the voltage VDD of the battery 43.

Further, the terminal (2) of the voltage detection circuit 41 is connected to the battery check terminal BC of the CPU 15, and is also connected to the battery voltage V01 via three resistors.

Note that the terminal (2) of the voltage detection circuit 41 is connected to ground.

The power supply disconnecting auxiliary transistor 31 and the power supply disconnecting main transistor 37 constitute a power supply disconnecting means together with the surrounding resistors, and in a normal state, both transistors are in an OFF state, and in this OFF state, , the supply of the battery voltage VDD to the terminal ■ of the voltage detection circuit 41 is stopped, and as a result, the voltage detection circuit 4■
This prevents the power of the battery 43 from being consumed. and,
When the CPU 15 supplies a battery scanning signal to the power supply disconnection auxiliary transistor 31 via the battery scan terminal BS, the power supply disconnection auxiliary transistor 31 turns on, and
Furthermore, the main power supply disconnection transistor 376 is turned on, and as a result, the battery voltage VDD is supplied to the terminal (2) of the voltage detection circuit 41 via the power supply disconnection main transistor 37.
The voltage detection circuit 41 detects the battery voltage ■. . Detects the voltage and checks whether the voltage is normal, and if it is normal, it outputs a high-level on signal, and if it is not normal, it outputs a high-level on signal.
When the battery voltage is low, a low-level off signal is output, and these signals are supplied from the terminal (2) to the battery check terminal BC of the CPU 15.

FIG. 2(a) is a detailed internal circuit diagram of the voltage detection circuit 41. This voltage detection circuit 41 has a voltage dividing resistor 5 connected in series between the battery voltages to divide and supply the battery voltage.
The divided voltage from the connection point of 3.55 and the voltage dividing resistor 53.55 is supplied to one input terminal, and the reference voltage from the reference voltage source 57 is supplied to the other input terminal, and both voltages are compared. The voltage detection comparator 51 is composed of a voltage detection comparator 51, and five output N-channel open drain elements connected to the output of the voltage detection comparator 51.

FIG. 2(b) is a waveform diagram showing the operation of the voltage detection port R41 shown in FIG. 2(a). The waveform shown in (A) of the same figure is the voltage of the battery 43, and the waveform shown in (2) is the voltage detection port &
This is the waveform of the output signal from output (■) of @41. As described above, as can be seen from the waveform in FIG.
When the voltage drops below T, a low-level off signal is output, and when it is higher than a predetermined voltage VDRT, a high-level on signal is output.

Next, the operation will be explained with reference to the flowchart shown in FIG.

When a call request signal is input from the terminal device 4, this terminal call request signal is supplied to the INT input terminal of the CPU 15, which activates the CPU 15. The CPU 15 checks the battery voltage before starting the terminal call communication. In preparation for the check, first, before operating the voltage detection circuit 41, a reset signal is output from the reset output terminal R3T, and this signal makes the recovery transistor 25 conductive, and the recovery reset coil 9R of the latching relay 9 is turned on. A current is applied to the battery and the load conditions for checking the battery voltage are set (step 110). When checking the battery voltage, the load condition for the current flowing through the battery is set to the actual load line. More specifically, the driving current of the latching relay 9 is generally about 10 to 30 mA, whereas the operating current of the CPU 15 is as low as about 1 to 3 mA. When the voltage of '3! is detected, the voltage of the battery 43 is detected as a relatively high voltage, and '3! : If you try to operate the latching relay 9, the voltage of the battery 43 will drop, and as a result, the latching relay 9 will not operate properly. Reset coil 9R for recovery of switching relay 9
The current load conditions are set to be the same as those when the latching relay 9 is operated.

Next, while the current is flowing through the recovery reset coil 9R of the latching relay 9 via the recovery transistor 25, the CPU 15 supplies a battery scanning signal to the battery scanning terminal BS, and thereby the power supply disconnection auxiliary Main transistor 37 for power supply disconnection via transistor 31
is made conductive, and the voltage of the battery 43 is supplied to the voltage detection circuit 41 (step 120).

The voltage detection circuit 41 includes a main transistor 37 for disconnecting the power supply.
When the voltage of the battery 43 is supplied through the circuit, the voltage is detected. Voltage detection port #141 generates a high level signal when the voltage of the battery 43 is above a specified voltage, and outputs a low level signal when it is below the specified voltage. This signal is C
Supplied to battery check terminal BC of PU15,
5 (step 130), and if the voltage of this battery 43 is below the specified voltage, the battery scanning signal is turned off (step 140), and the reset signal from the reset output terminal R3T is turned off (step 15).
0), the CPU 15 stops operating.

On the other hand, in the check of step 130, if the heavy pressure of the battery 43 is higher than the specified voltage, the battery scanning signal is turned off (step 160), and the reset output terminal R8 is turned off.
Turn off the reset signal from T (step 170)
, then the CPU 15 outputs the set output terminal S ET
” outputs a set signal (step 180), thereby operating the disconnecting set coil 9S of the latching relay 9 via the disconnecting transistor 27, and opening the break contact 9b of the latching relay 9. As a result,
The telephone R5 is disconnected from the telephone line 7, and the network control device becomes capable of data communication with the center device 1. The disconnection set coil 9S of the latching relay 9 operates, the break contact 9b of the latching relay 9 opens, and the telephone 5
When the telephone port 117 is disconnected, the CPU 15 turns off the set signal from the set output terminal SET (step 190), and performs terminal call communication processing (step 200).
). Then, when the terminal communication process is finished, the CPU 15
outputs a reset signal from the reset output terminal R3T (step 21○), thereby operating the recovery reset coil 9R of the latching relay 9 and closing the break contact 9.
b, connect the telephone 5 to the telephone line 7 again, and then turn off the reset signal (step 220), CP
UI 5 stops working.

〔Effect of the invention〕

As explained above, according to the present invention, the voltage detection means is connected to the operating power source only before operating the switch means for disconnecting the telephone from the telephone line, and a current of the same value as the current flowing through the switch means is applied to the operating power source. Since the voltage of the operating power supply is detected under the same load conditions, and at other times the voltage detection means is separated from the operating power supply, it is possible to reduce the e-current consumption and to ensure that the telephone is not used at all. It is possible to prevent malfunctions that would result in failure, and to perform highly reliable operations.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a main part of a network-side TN device according to an embodiment of the present invention, and FIGS. 2(a) and (b) respectively show a voltage detection circuit used in the network control device of FIG. A circuit configuration diagram and an operation waveform diagram, FIG. 3 is a system configuration diagram to which the network control device of FIG. 1 is applied, and FIG. 4 is a flowchart showing the operation of the network control device of FIG. 1. DESCRIPTION OF SYMBOLS 1... Center device, 2... Telephone switching network, 3... Network control device, 4... Terminal device, 5... Telephone set, 7... Telephone line, 9... Latching relay 15 ...CPU, 31...Auxiliary transistor for power supply disconnection, 37...
Main transistor for power supply disconnection, 1. Voltage detection circuit, 43. Battery.

Claims (1)

[Claims] a network control device that is connected to a telephone line in parallel with the telephone set and controls data transmission via the telephone line, the switch means operating to disconnect the telephone set from the telephone line during data transmission; voltage detection means for detecting the voltage of the operating power source before operating the switch means;
a power supply disconnecting means for connecting the voltage detecting means to the operating power source only when the voltage detecting means detects the voltage of the operating power source, and disconnecting the voltage detecting means from the operating power source at other times so that the voltage detecting means does not consume power; A network control device characterized in that, when the detection means detects the voltage of the operating power source, a current having the same value as the current flowing through the switching means is caused to flow from the operating power source to make the load conditions the same.