JPH098947A - Communication system - Google Patents

Abstract

PURPOSE: To detect a discontinuity between a T-NCU and a microcomputer meter and between the microcomputer meter and an interlocking device. CONSTITUTION: In the case of detecting a discontinuity between a microcomputer meter 9 and a network controller 5, the microcomputer meter 9 throws switches 53, 55 respectively to the position of terminals 61, 63, and a loops is formed by a terminal 57, a photo diode 49, a terminal 63, the switch 55, terminals 39, 35, a photo diode 29, terminals 33, 37, the switch 53 and the terminal 61. A current (discontinuity check signal) is supplied to the loop from the terminal 57. When no discontinuity exists in a twisted pair wire 7, the discontinuity check signal is supplied to the loop, the photo diode 49 is lighted, a photo transistor (TR)51 is conductive, a detection circuit 43 detects the conduction of the photo TR51 to recognize it that no discontinuity exists. When a discontinuity exists in the twisted pair wire 7, since no discontinuity check signal flows to the loop, the photo diode 49 is not lighted and the photo TR51 is not conductive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system using a microcomputer meter such as an automatic meter reading system or an alarm interlocking system.

[0002]

2. Description of the Related Art Recently, an automatic meter reading system that sends a guideline value of a gas microcomputer meter or the like to a center via a public line, or an alarm device detects a gas leak in order to ensure the safety of gas supply, the microcomputer meter detects the gas leakage. Alarm interlocking systems that cut off the supply of electricity are becoming widespread.

FIG. 6 shows a T-NC in an automatic meter reading system.
FIG. 3 is a diagram showing a U (network control device) 101 and a microcomputer meter 103. As shown in FIG. 6, the T-NCU 101 has an interface circuit 107, and the interface circuit 107 has a photocoupler 109, a photocoupler 111, and a capacitor 113. The photocoupler 109 has a photodiode 115 and a phototransistor 117,
The photocoupler 111 has a photodiode 119 and a phototransistor 121. The T-NCU 101 is connected to a center (not shown) via a public line. A circuit (not shown) for applying a current to the photodiode 115 according to a signal from the center side.
Is connected. Further, a circuit (not shown) for transmitting on / off of the phototransistor 121 to the center side is connected to the phototransistor 121.

The microcomputer meter 103 is constructed as follows. The terminal 139 is connected to the power supply voltage Vcc, and the terminal 1
The resistor 131 and the resistor 133 are connected to 39. Terminal 12
The switch 135 connected to 7 has terminals 141 and 14
3 is switched, and the switch 137 connected to the terminal 129 switches the terminals 145 and 147. The terminal 141 is connected to the resistor 131, and the terminal 143 is grounded. Similarly, terminal 145 is connected to resistor 133 and terminal 147 is grounded.

T-NCU 101 and microcomputer meter 103
Are connected by a twisted pair wire 105. That is, the terminal 123 and the terminal 127, and the terminal 125 and the terminal 1
29 is connected by a twisted pair wire 105.

Next, the T-NCU 101 and the microcomputer meter 1
The operation of exchanging electronic messages in 03 will be described. When the microcomputer meter 103 receives the downlink message D from the center, the switches 135 and 137 are always connected to the terminals 141 and 147, respectively, as shown by the solid line.
Phototransistor 1 according to the down line D from the center
17 turns on and off. When the phototransistor 117 is on, current flows from the terminal 139 connected to the power supply voltage Vcc to the terminal 141, the terminal 127, the terminal 123, the phototransistor 117, the terminal 125, the terminal 129, and the terminal 147. No current flows in the off state. Therefore, the phototransistor 11
The voltage value of the terminal 141 changes according to the on / off state of the terminal 7, and the microcomputer meter 103 can receive the downlink message D by measuring this voltage.

When sending the upbound electronic message E from the microcomputer meter 103 to the center, the switch 135 is connected to the terminal 143. The switch 137 switches the connection between the terminal 145 and the terminal 147 according to “1” or “0” of the upstream electronic message E from the microcomputer meter 103. Switch 137 is terminal 1
No current flows through the photodiode 119 of the photocoupler 111 when it is connected to the switch 47.
When is connected to the terminal 145, a current flows through the photodiode 119 of the photocoupler 111. When a current flows through the photodiode 119, the phototransistor 1
21 turns on, and when no current flows through the photodiode 119, the phototransistor 121 turns off.
By turning on / off the photocoupler 111 as described above, the upstream electronic message E can be sent to the center.

FIG. 7 shows the interlocking device 149 and the microcomputer meter 103 in the alarm interlocking system. Figure 7
As shown in, the interlocking device 149 has an interface circuit 153, and the interface circuit 153 is provided with a photo coupler 155 and a capacitor 157. The photocoupler 155 includes a photodiode 159 and a phototransistor 161. The interlocking device 149 is connected to a gas alarm (not shown), and the photodiode 159 receives the photodiode 159 in response to a signal from the gas alarm.
A circuit (not shown) for applying a current is connected to. The configuration of the microcomputer meter 103 is similar to that shown in FIG.

The interlocking device 149 and the microcomputer meter 103 are connected by a twisted pair wire 151. That is, the terminal 163 and the terminal 127, and the terminal 165 and the terminal 12
9 and 9 are connected by a twisted pair wire 151.

Interlocking device 149 to microcomputer meter 103
The operation when sending the cutoff message F to will be described. Switch 1
The switch 35 and the switch 137 are always connected to the terminals 141 and 147, respectively, as shown by the solid line. The phototransistor 161 is turned on / off according to the cutoff message F from the gas alarm. When the phototransistor 161 is turned on, the terminal 1 to the terminal 1 connected to the power supply voltage Vcc
41, terminal 127, terminal 163, phototransistor 1
A current flows through 61, the terminal 165, the terminal 129, and the terminal 147, but no current flows when the phototransistor 161 is off. Therefore, the voltage value of the terminal 141 changes according to ON / OFF of the phototransistor 161, and by measuring this voltage, the microcomputer meter 103 can receive the interruption message F.

[0011]

However, in such a communication system, between the T-NCU 101 and the microcomputer meter 103, and between the microcomputer meter 103 and the interlock device 1.
Since the disconnection with the cable 49 cannot be detected, when the disconnection occurs, the disconnection state may be left until the next communication event occurrence timing. Further, in the case of FIG. 6, even if communication is attempted when a disconnection occurs, the only result is that communication is impossible,
It may be difficult to obtain useful information for maintenance at an early stage. Further, in the case of FIG. 7, even if an attempt is made to perform interlocking disconnection when a disconnection occurs, it is feared that the disconnection will not succeed due to the disconnection and a dangerous situation may occur.

The present invention has been made in view of the above problems, and its object is to provide a T-NCU101.
Another object is to provide a communication system capable of detecting the disconnection between the microcomputer meter 103 and the microcomputer meter 103 and the interlocking device 149.

[0013]

In order to achieve the above-mentioned object, a first invention is to connect a microcomputer meter to a network control device connected to a public line so that communication can be performed between the public line and the microcomputer meter. In the communication system to be performed, the communication system is provided with a determination means for determining disconnection of a line between the microcomputer meter and the network control device.

A second aspect of the invention is a communication system in which a microcomputer meter is connected to an interlocking device connected to an alarm device for detecting a gas leak, and an alarm signal is sent from the alarm device to the microcomputer meter when a gas leak occurs. It is a communication system comprising a second judging means for judging whether or not there is a disconnection between the interlocking device and the microcomputer meter.

[0015]

According to the first aspect of the present invention, a loop is formed between the microcomputer meter and the network control device, and it is detected whether or not a current flows through this loop to detect whether or not there is a wire break between the network control device and the microcomputer control device. To judge.

Further, in the second invention, a loop is formed between the microcomputer meter and the interlocking device, and it is detected whether or not a current flows in this loop to detect whether or not there is a disconnection between the microcomputer meter and the interlocking device. To judge.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram of a communication system using a microcomputer meter 9 according to an embodiment of the present invention. As shown in FIG. 1, the center 1 is connected to the T-NCU via the public line 3.
The network controller 5 is connected, and the T-NCU 5 is connected to the microcomputer meter 9 via the twisted pair wire 7. The microcomputer meter 9 is connected to the interlocking device 1 via the twisted pair wire 15.
3 and the interlocking device 13 is connected to the gas alarm 11.

When performing automatic meter reading or the like, the microcomputer meter 9 sends data such as measured gas flow rate and pressure to the center 1 through the twisted pair line 7, T-NCU 5 and public line 3. When the gas alarm 11 detects a gas leak, it sends a signal to the interlocking device 13 to shut off a shutoff valve (not shown) of the microcomputer meter 9. The interlocking device 13 to which the shutoff signal is sent from the gas alarm device 11 sends a shutoff signal to the microcomputer meter 9 via the twisted pair wire 15, and the shutoff valve of the microcomputer meter 9 is shut off.

That is, the microcomputer meter 9 in this embodiment
In the communication system using, a system that communicates with the center 1 for automatic meter reading or the like via the twisted pair wire 7,
Alarm 1 for safety measures via twisted pair wire 15
And an alarm interlocking system that receives a signal from the device 1.

As a first embodiment, the T-NCU 5 and the microcomputer meter 9 in the communication system for automatic meter reading will be described. FIG. 2 is a diagram showing the T-NCU 5 and the microcomputer meter 9. As shown in FIG. 2, the T-NCU 5 has an interface circuit 17,
Is photocoupler 19, photocoupler 21, capacitor 2
3 The photo coupler 19 is the photodiode 2
5, having a phototransistor 27, a photocoupler 21
Has a photodiode 29 and a phototransistor 31. The T-NCU 5 is connected to the center 1 via the public line 3. A circuit (not shown) for applying a current to the photodiode 25 according to a signal from the center 1 is connected to the photodiode 25. Also, the phototransistor 3
A circuit (not shown) for transmitting on / off of the phototransistor 31 to the center 1 is connected to 1.

The microcomputer meter 9 is constructed as follows. Terminal 57 is connected to power supply voltage Vcc, and terminals 57 are connected to resistors 45 and 47. The switch 53 connected to the terminal 37 switches the terminal 59 and the terminal 61, and the switch 55 connected to the terminal 39 switches the terminal 63 and the terminal 65. The terminal 59 is connected to the resistor 45 and the terminal 61 is grounded. A photo coupler 41 is provided between the resistor 47 and the terminal 63.
Is provided. The photo coupler 41 is the photodiode 4.
9 and a phototransistor 51, and the detection circuit 43 is connected to the phototransistor 51. Detection circuit 43
Is for detecting conduction of the phototransistor 51. The terminal 63 is connected to the photodiode 49, and the terminal 65 is grounded.

The T-NCU 5 and the microcomputer meter 9 are connected by a twisted pair wire 7. That is, the terminal 33 and the terminal 37, and the terminal 35 and the terminal 39 are connected by the twisted pair wire 7.

First, the operation of exchanging electronic messages between the T-NCU 5 and the microcomputer meter 9 will be described. When the microcomputer meter 9 receives the downlink message A from the center 1, the switch 53 and the switch 55 are always connected to the terminal 59 and the terminal 65, respectively, as shown by the solid line. The phototransistor 27 is turned on / off in response to the downlink message A from the center 1. When the phototransistor 27 is turned on, the terminals 57 to 59 and the terminal 3 connected to the power supply voltage Vcc are connected.
Current flows through 7, the terminal 33, the phototransistor 27, the terminal 35, the terminal 39, and the terminal 65, but no current flows when the phototransistor 27 is off. Therefore, the voltage value of the terminal 59 changes depending on whether the phototransistor 27 is turned on or off. By measuring this voltage, the microcomputer meter 9 can receive the downlink message A.

When sending the upstream message B from the microcomputer meter 9 to the center 1, the switch 53 is connected to the terminal 61.
The switch 55 switches the connection between the terminal 63 and the terminal 65 in accordance with “1” or “0” of the upstream message B from the microcomputer meter 9. No current flows through the photodiode 29 of the photocoupler 21 when the switch 55 is connected to the terminal 65, but a current flows through the photodiode 29 of the photocoupler 21 when the switch 55 is connected with the terminal 63. When a current flows through the photodiode 29, the phototransistor 31 turns on and the photodiode 2
When no current flows through 9, the phototransistor 31 is turned off. By turning on / off the photocoupler 21 as described above, the upstream message B can be sent to the center 1.

Next, the operation for inspecting the presence / absence of disconnection between the T-NCU 5 and the microcomputer meter 9 will be described. FIG.
Is a flow chart showing a procedure for a disconnection inspection between the T-NCU 5 and the microcomputer meter 9. Normal time switch 5
3. Since the switch 55 is in the position indicated by the solid line, no current flows in the photodiode 49 of the photocoupler 41. When the disconnection is detected, the microcomputer meter 9 switches the switch 53 and the switch 55 to be connected to the terminal 61 and the terminal 63, respectively (step 301). In this case, terminal 5
7, photodiode 49, terminal 63, switch 55,
Terminal 39, terminal 35, photodiode 29, terminal 3
Since a loop is formed by 3, the terminal 37, the switch 53, and the terminal 61, and the terminal 57 is connected to the power supply voltage Vcc, a current (disconnection inspection signal) is passed through this loop (step 302). If there is no break in the twisted pair wire 7,
A disconnection inspection signal flows in this loop, and the photodiode 4
9 is turned on, the phototransistor 51 becomes conductive, the detection circuit 43 detects the conduction of the phototransistor 51, and it is considered that there is no disconnection. When the twisted pair wire 7 is disconnected, the disconnection inspection signal does not flow in this loop, so that the photodiode 49 does not turn on and the phototransistor 51 does not conduct.

In this way, the detection circuit 43 detects the conduction of the phototransistor 51 (step 30).
3) If the phototransistor 51 is conductive, it is determined that the twisted pair wire 7 is not broken (step 30).
4). When no current flows through the photodiode 49 and the detection circuit 43 does not detect the conduction of the phototransistor 51 (step 303), it is determined that there is disconnection (step 3).
05). Then, the switch 53 and the switch 55 are switched to the terminal 59 and the terminal 65, respectively (step 306).

Here, the disconnection inspection signal is a mark signal of about 20 ms, which is 150 ms to 250 ms of the communication message.
It can be distinguished from the mark signal of the degree. Furthermore, since the signal has a short duration of about 20 ms, it is possible to suppress power consumption due to the disconnection inspection signal transmission. The frequency of sending the disconnection inspection signal is determined in consideration of power consumption reduction and rapid detection of disconnection. For example, when the disconnection inspection is performed once a day, the power consumption at the time of transmitting the disconnection inspection signal is 20 mA, and the current consumption capacity for 10 years is 20 (mA) × 20 (msec) × 36.
5 (days) × 10 (years) = 0.4 mAh, and the power consumption associated with the disconnection inspection is small.

As described above, according to this embodiment, the T-NCU is
Since disconnection between 5 and microcomputer meter 9 can be detected,
It is possible to prevent an event in which communication cannot be performed due to disconnection when an emergency call occurs. In addition, the disconnection can be detected without increasing the number of additional circuits and increasing the power consumption. In the present embodiment, the photocoupler 41 for detecting disconnection and the detection circuit 43 are connected to the microcomputer meter 9
The photo coupler 41 and the detection circuit 43 are provided in the TN.
It may be provided on the CU5 side.

Further, the disconnection detecting photocoupler and the detecting circuit may be provided in the RF adapter (wireless communication terminal for automatic meter reading). The RF adapter has a master unit connected to the T-NCU 5 and a slave unit connected to the microcomputer meter 9.
-Used for wireless communication between the NCU 5 and the microcomputer meter 9.

As a second embodiment, the microcomputer meter 9a and the interlocking device 13 in the alarm interlocking system will be described. FIG. 4 is a diagram showing the microcomputer meter 9a and the interlocking device 13. As shown in FIG. 4, the interlocking device 13 has an interface circuit 67.
A photocoupler 69, a photocoupler 71, a capacitor 75, and a detection circuit 73 are provided therein. The photocoupler 69 has a photodiode 77 and a phototransistor 79. The photocoupler 71 has a photodiode 81 and a phototransistor 83. The interlocking device 13 is connected to the gas alarm device 11, and the photodiode 77 is connected to a circuit (not shown) that applies a current to the photodiode 77 in response to a signal from the gas alarm device 11. When the photodiode 81 of the photocoupler 71 lights up, the phototransistor 83 becomes conductive, and the detection circuit 73 detects the conduction of the phototransistor 83.

The microcomputer meter 9a and the interlocking device 13 are connected by a twisted pair wire 15. That is, the terminal 85 and the terminal 37, and the terminal 87 and the terminal 39 are connected by the twisted pair wire 15.

First, from the interlocking device 13 to the microcomputer meter 9
The operation when sending the interruption message C to a will be described. The switch 53 and the switch 55 are respectively connected to the terminal 5 as shown by the solid line.
9, always connected to terminal 65. The phototransistor 79 is turned on / off according to the cutoff message C from the gas alarm 11. When the phototransistor 79 is turned on, the terminal 57, the terminal 37, the terminal 85, the phototransistor 79, the terminal 87, which are connected to the power supply voltage Vcc, are connected.
Current flows through the terminals 39 and 65, but no current flows when the phototransistor 79 is off. Therefore, the voltage value of the terminal 59 changes depending on whether the phototransistor 79 is turned on or off, and the microcomputer meter 9a can receive the cutoff message C by measuring this voltage.

Next, the microcomputer meter 9a and the interlocking device 13
The operation in the case of inspecting for the presence / absence of a disconnection between and will be described.
FIG. 5 is a flow chart showing the procedure of the disconnection inspection between the microcomputer meter 9a and the interlocking device 13. Normally, the switch 53 and the switch 55 are in the positions indicated by the solid lines, so the terminal 5
7, terminal 59, switch 53, terminal 37, terminal 85, phototransistor 79, photodiode 81, terminal 8
A loop is formed by 7, the terminal 39, the switch 55, and the terminal 65. When the disconnection is detected, the interlock device 13 sends a disconnection inspection signal C2 to the photocoupler 69 (step 5).
02). When there is no break in the twisted pair wire 15, current flows in this loop, the photodiode 81 lights up, the phototransistor 83 conducts, and the detection circuit 73 detects conduction of the phototransistor 83 and considers that there is no break. . When the twisted pair wire 15 is broken, no current flows in this loop, so that the photodiode 81 does not light and the phototransistor 83 does not conduct.

In this way, the detection circuit 73 detects the conduction of the phototransistor 83 (step 50).
3) If the phototransistor 83 is turned on, it is determined that the twisted pair wire 15 is not broken (step 5).
04). When no current flows through the photodiode 81 and the detection circuit 73 does not detect the conduction of the phototransistor 83 (step 503), it is determined that there is disconnection (step 505). Then, the interlocking device 13 stops the output of the disconnection inspection signal C2 (step 506).

The disconnection inspection signal C2 is a signal of about 110 ms and can be distinguished from a mark signal of about 150 ms to 250 ms in a communication message. Furthermore, since the signal has a short duration of about 110 ms, the power consumption due to the disconnection inspection signal transmission can be suppressed, and even when current is applied from the microcomputer meter 9a to the twisted pair wire 15 by intermittent operation for about 100 ms, This signal can be distinguished. The frequency of sending the disconnection inspection signal is determined in consideration of power consumption reduction and rapid detection of disconnection. For example, when the disconnection inspection is performed once a day, the power consumption at the time of transmitting the disconnection inspection signal is 20 mA, and the current consumption capacity for 10 years is 20 (mA) × 110 (m
sec) × 365 (days) × 10 (years) = 2.3 mAh, and the power consumption associated with the disconnection inspection is small. Under normal conditions, the current consumption on the side of the microcomputer meter 9a is about the same as 2.3 mAh. The frequency of sending the disconnection inspection signal is determined in consideration of reduction of power consumption and rapid detection of disconnection.

As described above, according to the present embodiment, since the disconnection between the microcomputer meter 9a and the interlocking device 13 can be detected, it is possible to prevent the event that the interlocked disconnection cannot occur due to the disconnection when an emergency call occurs. it can. In addition, the disconnection can be detected without increasing the number of additional circuits and increasing the power consumption. Furthermore, it is possible to add a new alarm function that utilizes the detected disconnection status information.

As described above, according to the communication system of the present embodiment, the disconnection of the line connecting the T-NCU 5 and the microcomputer meter 9 or the line connecting the microcomputer meter 9a and the interlocking device 13 can be detected. When it happens, maintenance can be done promptly. For this reason, it is possible to avoid leaving the disconnection state, so that it is possible to prevent the occurrence of an event such as an inability to communicate or an interrupted disconnection when an emergency call occurs. In addition, by adding some circuits to the conventional technique, it is possible to provide a function of detecting a disconnection without increasing the power consumption.

[0038]

As described above in detail, the communication system according to the present invention can detect the disconnection between the T-NCU and the microcomputer meter and between the microcomputer meter and the interlocking device.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a communication system using a microcomputer meter 9 according to an embodiment of the present invention.

FIG. 2 is a diagram showing a T-NCU 5 and a microcomputer meter 9.

FIG. 3 is a flow chart showing a procedure for a disconnection inspection between the T-NCU 5 and the microcomputer meter 9.

FIG. 4 is a diagram showing a microcomputer meter 9a and an interlocking device 13;

FIG. 5 is a flowchart showing a procedure of a disconnection inspection between the microcomputer meter 9a and the interlocking device 13.

FIG. 6 is a diagram showing a T-NCU 101 and a microcomputer meter 103.

FIG. 7 is a diagram showing a microcomputer meter 103 and an interlocking device 149.

[Explanation of symbols]

1 ... Center 3 ... Public line 5 ... T-NCU 7,15 ... Twisted pair line 9,9a ... Micon meter 11 ... Alarm 13 ... Interlocking device 17,67 ... ...... Interface circuit 19, 21, 41, 69, 71 ...... Photo coupler 23, 75 ...... Capacitor 25, 29, 49, 77, 81 ... Photo diode 27, 31, 51, 79, 83 ...... ... Phototransistors 33, 35, 37, 39, 57, 59, 61, 63, 6
5, 85, 87 ... Terminal 43, 73 ... Detection circuit 45, 47 ... Resistance 53, 55 ... Switch

Claims (6)

[Claims] 1. A communication system in which a microcomputer meter is connected to a network control device connected to a public line and communication is performed between the public line and the microcomputer meter, wherein a disconnection between the microcomputer meter and the network control device. A communication system comprising: a determination unit that determines the presence or absence of 2. The determination means detects a means for forming a loop between the microcomputer meter and the network controller, a means for applying a current to the loop, and a detection as to whether or not a current flows through the loop. The communication system according to claim 1, further comprising: 3. The communication according to claim 2, wherein the detection unit includes a photocoupler provided in the loop, and a detection unit configured to detect conduction of a phototransistor in the photocoupler. system. 4. A communication system in which a microcomputer meter is connected to an interlocking device connected to an alarm device for detecting a gas leak, and when the gas leaks, an alarm signal is sent from the alarm device to the microcomputer meter. A communication system comprising: a determination unit that determines whether or not a wire breakage occurs between the meter and the meter. 5. The determining means detects a means for forming a loop between the microcomputer meter and the interlocking device, a means for applying a current to the loop, and whether or not a current flows in the loop. The communication system according to claim 4, further comprising: a detection unit. 6. The communication according to claim 5, wherein the detection means includes a photocoupler provided in the loop, and a detection means for detecting conduction of a phototransistor in the photocoupler. system.