JPS5922474A - Monitor information transmitting system in remote supervisory system - Google Patents

Abstract

PURPOSE:To perform rationally the processing control when a line is busy, by performing the check whether or not monitor information is transmitted correctly, retransmission and alarming and the like, when transmitting the monitor information to a monitor station with the use of a telephone exchange line network. CONSTITUTION:The alarm display is performed if no response is obtained regardless of repetitive calling of a master station, in transmitting the monitor information of a slave station to the master station via a telephone line. The line is released, when the master station responds but no information transmission request signal ENQ exists, that is, in case of misdialing. A slave station receiving the ENQ signal transmits the monitor information repetitively for plural number of times. The master station transmits an ACK signal when the information is confirmed and an NAK signal when the information is received incompletely. The slave station releases the line acquisition when the ACK signal is received and performs retransmission when the NAK signal is received. When the number of retransmissions exceeds a prescribed number of times, the line acquisition is released once and the line is caught again after a prescribed time for the retransmission of the information. When the release of the line and reacquisition exceed a prescribed number of times, the line acquisition is stopped and the alarm display is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a remote monitoring system that remotely monitors electrical equipment, etc., using a telephone exchange network, such as a subscriber telephone line, and particularly relates to a remote monitoring system that remotely monitors electrical equipment, etc. Monitoring information that has the function of checking whether the information has been correctly transmitted to the central monitoring equipment installed at the monitoring station through the above-mentioned telephone exchange network, and attempting to retransmit it as necessary, or issuing an alarm. This relates to transmission methods.

For example, when maintaining electrical equipment, conventionally it has been common for maintenance personnel to make regular rounds, but this patrol-based maintenance method does not allow constant monitoring of electrical equipment for abnormalities. Not only is this possible, but it also increases labor costs and maintenance costs, so in recent years, sensors that correspond to monitored events have been installed in monitored electrical equipment, and when there is a change in the state of the monitored event, it is possible to detect the change in state. A system has been proposed that automatically sends the information shown to a central monitoring device via a telephone switched line network. As a result, efforts are being made to reduce maintenance costs.

In the above system, information is generally transmitted using the subscriber switched telephone network that is normally used for telephone calls. Therefore, when the subscriber switched telephone network is busy, information is not transmitted. Therefore, how to control processing in such cases becomes an important issue for this type of system.

The present invention aims to provide a rational method for controlling the processing.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram of a remote monitoring system for electrical equipment according to an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of the system shown in FIG. 1, and FIG. 3 is a diagram showing the format of transmitted information. .

In Fig. 1, A is a status detection and information transmission device installed on the electrical equipment side (hereinafter referred to as a slave station), B is a centralized monitoring device installed in a monitoring station (hereinafter referred to as a master station), and C is a
D is the subscriber telephone switching network (including the subscriber telephone line, the exchange where slave station A is accommodated, the exchange where master station B is housed, the relay exchanges and relay telephone lines between the exchanges, etc.), D is the subscribed telephone line of slave station A, and E is the subscribed telephone line of master station B.

In slave station A, 1, 2 and 3 are abnormality detection sensors, 4
5 is a transmitter, 5 is a telephone, 6, 7 and 8 are transmission lines for detection signals detected by sensors 1, 2 and 3, and 9 is a communication line.

In the transmitter 4, 40 is an information input section, 41, 42 and 43 are abnormality monitoring sections, 44 is a control section, 45 is a storage section, 46
4 is a display unit; 47 is a modulation and demodulation unit for transmitting information and input information;
8 is a network control section, and 49 is an abnormality alarm section.

The events to be monitored in the embodiment shown in FIG. 1 are three items: insulation failure monitoring, overload monitoring, and power outage monitoring, and for each event, the sensors 1, 2 and 3, and the abnormality monitoring unit 41. 42 and 43 are provided. In the following explanation, the sensor 1°2.3 and the abnormality monitoring parts 41, 42 will be described.
．． 43 individually, sensor 1 is an insulation defect detection sensor, sensor 2 is an overload detection sensor, sensor 3 is a power outage detection sensor, and abnormality monitoring unit 41 is an overload detection sensor. The insulation defect monitoring section and the abnormality detection section 4
2 is called an overload monitoring section, and the abnormality detection section 43 is called a power outage monitoring section, respectively.

The insulation defect detection sensor 1 is provided for the purpose of detecting insulation defects in electrical equipment that occur due to aging or poor construction, and prevents electrical leakage accidents. Or, it consists of a leakage current detector installed through the grounding wire of the transformer, and a leakage current larger than the preset current value flows through this detector to the above-mentioned low voltage side distribution line or grounding wire. The device is configured to detect this and generate an output when it occurs.

The overload detection sensor 2 is provided for the purpose of preventing deterioration of electrical equipment due to operation in an overload state, and performs overload monitoring by monitoring the temperature of the windings in the substation transformer. This is accomplished by a temperature sensor installed inside or on the outside of the transformer, and when the temperature of the winding rises to a value higher than a preset temperature value, the sensor detects the temperature. is configured to detect and generate an output.

The power outage detection sensor 3 is provided for the purpose of early detection of a power outage (power outage) to electrical equipment. The detector is configured to detect and generate an output when the received voltage or the distributed voltage falls below a certain set value.

When each of the sensors 1, 2.3 detects an abnormality or returns to normal, the transmitter 4 displays the contents and automatically calls the master station B. It has the function of transmitting the detected information, and is connected to the sensors 1, 2゜3 by signal transmission lines 6, 7, 8, and is mainly installed in the office or manager's room on the electrical equipment side. will be installed.

The telephone 5 is used for making calls over a subscriber telephone line used for the electric equipment remote monitoring system, and is connected to the transmitter 4 via a telephone line 9.

Next, each part constituting the transmitter 4 will be explained.

The information input section 40 performs level conversion on the detection signals inputted from each of the sensors 1.2.3 via the signal transmission lines 6, 7.8 so as to be suitable for input to the abnormality monitoring section 41.42.43. Performs signal processing such as

The insulation defect monitoring unit 41 measures the duration of the detection signal from the insulation defect detection sensor 1 that is input via the detection/signal input line 411, and when the detection signal continues for a set time or more, the abnormality information output line 41D is output. Sends insulation defect information to.

That is, the short-time detection signal from the insulation failure detection sensor 1 is excluded from sending out insulation failure information, thereby preventing false alarms.

The overload monitoring unit 42 measures the duration of the detection signal from the overload detection sensor 2 that is input via the detection signal input line 42I, and when the detection signal continues for a set time or more, outputs the signal to the abnormality information output line 42D. Sends overload information. The purpose of measuring the duration of the detection signal is the same as in the insulation failure monitoring section 41 described above.

The power outage monitoring unit 43 measures the duration of the detection signal from the power outage detection sensor 3 that is input via the detection signal input line 43I, and outputs power outage information to the abnormality information output line 43D when the detection signal continues for a set time or more. Send out. The purpose of measuring the duration of the detection signal is the same as in the insulation failure monitoring section 41 described above.

The control unit 44 has abnormality 1 stomach report output lines 41D and 42D.

43D is read at regular intervals, and from that state, the contents of the storage unit 45 are updated as necessary, and the status display unit 4
6, the generation of alarms by the abnormality alarm section 49, and the sending of information via the network control section 48. It is mainly composed of a microcomputer, and performs the above-mentioned time control according to a certain GLODARAM. conduct.

The storage unit 45 constantly stores the latest status of monitored events under the control of the control unit 44, and whether or not information should be transmitted to the master station B depends on the information stored in the storage unit 45 and the sensor. This is determined by the control unit 44 by comparison with the monitoring information based on the detection signal according to No. 1 and 2.3.

The modulation/demodulation section 47 modulates the information to be sent to the parent station B into a signal form suitable for transmission via the subscriber telephone switching network C, and sends the information to the parent station B.
It demodulates the signal sent from the control unit 44 into a signal form suitable for input to the control unit 44.

The network control unit 48 acquires and releases the subscriber telephone line under the control of the control unit 44, transmits the dial number of the master station B, and also transmits a signal indicating whether or not the telephone 5 is in use. It has functions such as detecting the response of the master station B.

Next, the operation of the embodiment will be explained with reference to FIGS. 2 and 3.

First, Table 1 shows the software set by the control unit 44 during operation of the slave station A, and Table 2 shows the control signals sent from the master station B to the slave station A.

Table 1 Table 2 When the remote monitoring operation of the electrical equipment by the monitoring system starts, the control unit 44 reads the states of the abnormality information output lines 41D, 42D, and 43D at each set period. That is, the state of the monitored event detected by the sensors 1, 2, and 3 is read ((1) in the flowchart shown in FIG. shall indicate the above code). Next, the information stored in the storage section 45 is read out via the information input/output line 45I, and this information is compared with the information read from the abnormality information output lines 41D, 42D, and 43D (2).

- Assuming that normal information is initially stored in the storage unit 45, when none of the sensors 1.2.3 detects an abnormal state, the abnormality detection unit 41.42.43 detects an abnormal state. Information output lines 41D and 42D.

Since no abnormality information is output to 43D, the above comparison operation (based on the result of 3), that is, since the information on both sides is not different, the control performs the operation shown in 70-chart (a
), and it is determined whether the transmission flag is set (4). In this case, since there is no setting of the transmission flag (the setting of the transmission flag will be described later), control proceeds in the direction of (b) and returns to the starting point. Abnormality information output line 41D.

While no abnormality information is output to 42D and 43D, the above operation, that is, "(1) → (2)" shown in the flowchart is performed.
→ (3) → (a) → (4) → (b) → (1)'' control routine is repeated every set cycle of the monitoring operation, and normal information remains stored in the storage unit 45. Normal information is displayed on the display section 46. During the repetition of this control routine, the state of the monitored event is continuously monitored, and the slave station A is in the state monitoring mode.

When at least one of the sensors 1.2.3 detects an abnormality in the monitored event and the corresponding abnormality monitoring unit 41, 42 or 43 sends abnormality information to the abnormality information output line 41D, 42D or 43D, the above-mentioned memory In the comparison operation (3) between the stored information and the read information of the storage section 45, the control proceeds in the direction (C), and the stored information of the storage section 45 is transferred to the information input/output line 4.
Please update to new information including the above abnormal information via 5I.
), the information stored in the storage section 45, ie, the new information, is sent to the display signal sending line 46I, and the new information is displayed on the display section 46 (6). Also, based on the fact that the information on both sides is different in the comparison operation (3), a transmission flag is set in the control unit 44 (7), and the slave station A transmits the new information to the master station B.
The controller starts controlling the data to be transmitted and enters information transmission mode.

Next, determine whether or not timer C shown in Table 1 above is set. (8) (The setting of timer C will be described later.) In this case, timer C is not set. Control proceeds in the direction of (d) and a determination is made as to whether the telephone 5 is in use (9).

Assuming that telephone 5 is not in use, the name and control are (,
), a control signal is sent to the network control signal output line 481, the network control unit 48 is activated, the subscriber telephone line is captured, and the dial number of the parent station B is transferred from the network control unit 48 to the subscriber station B. It is sent to the telephone line (10).

When the transmission of the dial number to the subscriber telephone line is completed, the control unit 44 sets timer B to monitor the response from master station B.
is set (11). After setting timer B, the response of base station B is determined by, for example, reversing the polarity of the subscriber telephone line (in subscriber switched telephone network C, generally when the called party answers, the polarity of the subscriber telephone line of the calling party is reversed). The response information is transmitted to the calling party.) Upon detection, the network control unit 48 monitors (12).

While there is no response from master station B, control proceeds in the direction of (f), and it is determined whether the time set by timer B has elapsed, that is, whether timer B has timed out (
13). If timer B is not in time, control proceeds in the direction of (g), and the response of master station B is monitored again. In this way, until there is a response from the master station B within the time set by timer B, the r
(12) → (f) → (13) → (g) → (12) J
The control operation is repeated, and when there is a response from the master station B, the process proceeds in the direction of control 75qh).

When there is a response from master station B, an information transmission request signal (ENQ signal) is received from master station B. (After the response, master station B sends an ENQ signal to slave station A when it is ready to receive information.) A timer D is set in the control unit 44 to monitor (14).

After setting timer D, control is performed to determine whether or not the 18NQ signal from master station B has been received (15).
While the NQ signal is not received, the control proceeds in the direction of (1), and it is determined whether or not the timer D has reached the time limit (16). If timer D does not time out, control proceeds in the direction of (j), and the KNQ from master station B is returned.
Signal reception is monitored. In this way, within the time set by timer D, until the ENQ signal from master station B is received, r (15)→(1) shown in the flowchart is executed.
→−(16)→(j)→(15) The control operation of J is repeated.

After responding to the call from slave station A, master station B transmits the above-mentioned ENQ signal requesting slave station A to send all information via subscriber telephone switching network C, when preparations for receiving information are completed. The signal is modulated into a signal format suitable for the purpose and sent out. In the slave station A, the 13NQ signal is received by the network control unit 48 and inputted to the modulation/demodulation unit 47 via the transmission information input/output line 47D, where it is demodulated into a signal form suitable for control processing by the control unit 44. The information is input to the control unit 44 via the transmission information input/output line 47I.

When the ENQ signal from the master station B is received within the time set by the timer D, the control proceeds in the direction (k), and the new information written in the storage section 45 is transferred to the information input/output line 45I.
is read out via the transmission information input/output line 47I, and modulated by the modulation/demodulation section 47 into a signal form suitable for transmission.
The information is transmitted to the subscriber telephone line via the transmission information input/output line 47D1 and the network control unit 48 (17).

The frame structure of the new information transmitted to the master station B is as shown in FIG.
), a slave station number code indicating the information transmission source, a monitoring information code of the monitored event (in the embodiment, an insulation information code, a load information code, and a power supply information code), and the slave station number code and monitoring information code are being transmitted. It consists of a check code for checking within the slave station A whether or not the frame has changed, and a control code (ETX) indicating the end of the frame. The slave station number code is added as information unique to the slave station A, and the check code is added after its bit configuration is determined from the contents of the monitoring information code and the slave station number code. Then, the new information constituted as a frame as described above is sent to the master station B multiple times, three times in this embodiment.

When the above new information is correctly received by the master station B, the master station B
sends a control signal (ACK signal) indicating complete reception of new information,
If the new information is not correctly received by the master station B, the master station B will send a signal (NAK signal) indicating incomplete reception of the new information.
Each signal is sent to slave station A in the same manner as the ENQ signal was sent. The slave station A receives the ACK signal or NAK signal in the same manner as the group Q signal.

Slave station A must determine whether the signal from master station B is an ACK signal or a NAK signal18), and if it is an ACK signal, the control is U>
Then, a telephone line release instruction signal is output to the network control signal output line 48I, and the network control section 48 releases the hold on the subscriber telephone line (19).

If the signal from R station B is a NAK signal, the control proceeds in the direction of (m) and adds "1" to the counter 2 set in the control unit 44 (20), and then It is determined whether or not the count value of 2 is rNJ, which is set as the number of ports for repeatedly sending new information (21), and since the count value is not rNJ at the beginning, the control is set to (n). The new information is transmitted to the master station B again. In this way, within the above setting value "81", slave station A receives ACK.
r (1
7)→(18) −+ (m) −+ (20) →(
21) -+ (n) -+ (17) The control operation of J is repeated, and when the reception of the ACK signal is confirmed, the control proceeds in the direction of (1), and in the same way as above, join + [talk line The trap is released (Step 9).

When slave station A is released from the subscriber telephone line, the set transmission flag is cleared (22), the transmission state is released, and if counter 1 and counter 2 are in the counting state (
Counter 1 will be described later. ), the corresponding counter 1
Then, the counter 2 is cleared (23), the control returns to the starting point, and the slave station A enters the status monitoring mode again.

If the new information is written in the storage section 45 and the new information is transmitted to the master station B while the telephone 5 is being used and the subscriber telephone line is blocked, the control proceeds to step (9) shown in the flowchart. Then, based on the judgment in (9), the control proceeds in the direction of (p), and first it is judged whether or not timer A for monitoring the continuous use time of the telephone 5 is set (24). . At the beginning when the flow of control proceeds in the direction (p), the timer A is not set, so the control proceeds in the direction (q), the timer A is set (25), and the timer A is set. be judged (
26].

When timer A does not time out, the control is (r
), returns to the starting point, and again reads the status of the monitored vehicle to elephant (1) and compares the information stored in the storage unit 45 with the information read above (2), but at this time Since the information stored in the storage unit 45 has already been updated to the new information, the control proceeds in the direction of (,) according to the judgment in (3) shown in the flowchart, and furthermore, in the judgment in (4), the control proceeds in the direction of (,). In this case, since the transmission flag has already been set, the control proceeds in the direction of (8), and after determining whether or not timer C is set (8), it is again determined whether the telephone 5 is in use. Judgment (9) is made.

That is, while the telephone 5 is in use within the time set by timer A, the process shown in the flowchart [(9)
→(p)→(24)→(1)→(26)→(r)→(1
)→(2)→(3) −) (a) −+ (4) −
+ (8) -+ (8) -+ (d) → (9)'' control operation is repeated, and if the telephone 5 is no longer in use and the subscriber telephone line becomes vacant, the network control unit 48 Based on the information, the control unit 44 detects that the subscriber telephone line has become vacant, and the control proceeds in the direction of (,), and thereafter the control operations described above from (10) shown in the flowchart are executed. proceed. Note that in the second and subsequent rounds of repeating the above control operation, timer A has already been set to one birth month, so after determining whether or not timer A is set (24),
The control proceeds in the direction (1), and the above control operation is repeated.

In repeating the above control operation, when the timer A times out, that is, when the telephone 5 is not used within the time set by the timer A, in the judgment (26) shown in the flowchart, The control proceeds in the direction of (u), and a signal indicating that new information has not been transmitted is sent from the control unit 44 to the display signal sending line 46I, and a display indicating that new information has not been transmitted is displayed on the display unit 46 (27). A signal is sent to the alarm signal output line 49I, and the abnormality alarm section 49 generates an alarm (28). After that, the control operation proceeds to (22) shown in the flowchart, where the transmission flag is cleared (22) and counter 1 is cleared (23L) as described above.
Control returns to the starting point. In other words, if the subscriber telephone line does not become free within the time set by timer A, the information transmission mode of slave station A is canceled without seizing the subscriber telephone line, and new information is not transmitted when the slave station enters the slave station. Only a non-transmission indication and an abnormality alarm are issued.

At the stage when the dial number of the master station B is sent over the subscriber telephone line and waiting for a response from the master station B, for example, when the master station B is already communicating with another slave station, the dial number is set by timer B. If there is no response from base station B within the specified time, that is, if timer B timeout is detected in judgment (13) shown in the flowchart, control proceeds in the direction of (v), and the subscriber telephone line is acquired. is canceled (29), and "1" is added to the counter 1 set in the control unit 44 (30),
Next, it is determined whether the counted value of the counter 1 is rMJ set as the number of calls of the master station B (3
1) When , r M, and J are not reached, the control is (
Proceeding in the direction of w), a timer C is set in the control unit 44 to set the re-call time interval for the subscriber telephone line (3).
2) Next, it is determined whether or not the timer C has timed out (33). At first, since the timer C has not timed out, the control proceeds in the direction of (,) and returns to the starting point. After that, the control is shown in the flowchart [(1)→(2)→(3)→(,)→(4)→(,
) → (8)'' At this time, timer C has already been set, so in the judgment of (8) shown in the time chart, the control advances in the direction of (y), and the timer C timer starts again. - is determined (33).

Until the timer C reaches timeout, that is, until the re-dialing time for the subscriber telephone line is reached, the process shown in the flowchart is (33)→(,)→(1)→(2)→
(3)→(&)→(4)→(,)→(8)→(y)→(
33) When the control operation of J is repeated and timer C times out, that is, when the re-transmission time comes, the control proceeds in the direction of (z) in the judgment (33) shown in the flowchart. Thereafter, the control operations described above from (9) shown in the flowchart proceed.

In the control operation from (9), if slave station A calls master station B and the state in which there is no response from the master station B continues,
The control operation is r (12) → (f) → (13) → (v) →
(29)→(30)→(31) Proceed in the direction of J, and this process is repeated. Then, by repeating the control operation, the addition to the counter 1 progresses, and when it is determined that the counted value has reached rMJ (31), the control advances in the direction of (aa), and the flowchart follows. The control operations described above proceed from (27) shown.

To summarize the above operation, when slave station A calls master station B at the stage of transmitting new information written in storage unit 45, if there is no response from master station B, timer C is set. The operation of calling the master station B is repeated at the time interval (cycle) and the number of times (M times) set by the counter 1, and if there is no response from the master station B after repeating this operation, The display unit 46 displays that new information has not been transmitted, the abnormality alarm unit 49 issues an alarm, the transmission flag is cleared, and the information transmission mode of the slave station A is released.

A communication path between slave station A and master station B through subscriber telephone switching network C is set up, and when slave station A is waiting for an INQ signal from master station B, for example, when a response from master station B is received from the telephone. If the call from slave station A is made by an incorrect dial and the called party is not the master station B, etc., the call will be received from the master station B within the time set by timer D. ENQ
No signal is sent. Therefore, in this case, the control is (ab) based on the judgment (16) shown in the flowchart.
From then on, the control operation described above from (29) shown in the flowchart proceeds, and the master station B is called M times set by counter 1 at the time interval set by timer C. If the ENQ signal is not received by the slave station A, the display unit 46 displays a message indicating that new information has not been transmitted, the abnormality alarm unit 49 issues an alarm, and the transmission flag is cleared to prevent the slave station A from transmitting information. mode is canceled.

In addition, at the stage when slave station A sends new information to master station B and slave station A waits for a confirmation signal (ACK signal or NAK signal) from master station B, the N times set in counter 2 are If a NAK signal is sent from master station B in response to the sending of new information, the control is started by determining whether the count value of counter 2 is (-NJ or not (21)). ), and after clearing the counter 2 counting "N" (J4), the control is shown in the flowchart (29)
After that, the control operations described above from (29) proceed. In other words, new information is sent to master station B N times set by counter 2, and if no ACK signal is received for any of them, the acquisition of the subscriber telephone line is temporarily released and the timer set by timer C is sent. After the time has elapsed, the subscriber telephone line is acquired again, the master station B is called, and new information is sent.
This control operation is repeated M times set by counter 1,
In either case, if the new information is not received correctly, the display section 46 displays an indication that the new information has not been transmitted, and the abnormality alarm section 4
9, the information is transmitted, the transmission flag is cleared, and the information transmission mode of slave station A is canceled.

In the above explanation, when the control progresses and cycles in the direction (X) from the judgment (33) shown in the flowchart,
Or, if the state of the monitored event changes while the control is progressing and cycling in the direction (r) from the judgment in (26), the control changes to the direction (c) based on the judgment in (3) shown in the time chart. The information stored in the storage unit 45 is updated, and the updated information is displayed on the display unit 46, but at this time, the information stored in the storage unit 45 is updated.
Since the transmission flag of slave station A has already been set and it is in the information transmission mode, the information transmission mode of slave station A does not change, just by repeating the operation (7) shown in the flowchart. Then, the latest state change that occurred during the above control cycle is transmitted to the master station B.

In the above explanation, the case where an abnormality was detected in either sensor 1, 2.3 was explained as an example.
The above control operation is also carried out when the abnormal state is resolved and the normal state is restored in a state where one of the two detects an abnormal state and the storage section 45 stores the abnormal state information. That is, the above can be easily understood since the information stored in the storage unit 45 is updated even in such a case. Furthermore, if the abnormal state continues after detecting the abnormal information and transmitting the abnormal information to the master station B, the information stored in the storage unit 45 will not be changed with the abnormal information, so the slave station A is a place where it is easy to understand that when the monitored event is abnormal, the same abnormal information is not sent again when the event is in the status monitoring mode, and furthermore, when the content of the abnormal state changes (e.g. When an overload condition of electrical equipment is being detected (or when a new insulation defect condition occurs), new abnormality information is sent to the master station B each time. This can also be easily understood since the information stored in the storage unit 45 is updated.

In addition, counter 1 counts the number of repeated calls made by slave station A when new information is not correctly transmitted to master station B after slave station A has acquired the subscriber telephone line. It is clear from the flowchart that the reason why the new information is not transmitted correctly does not matter.

This means that M times set as the number of repeated transmissions (including the first transmission) means the cumulative number of repeated transmissions due to all causes.

In the embodiments described above, the equipment to be monitored was electrical equipment, but the present invention can be applied to any type of equipment to be monitored as long as it is a system that remotely monitors the status using a telephone exchange network. However, the type of equipment to be monitored does not change the gist of the present invention.

Furthermore, in the embodiments described above, the information is sent by the so-called event transmission method, which is carried out when there is a change in the state of the monitored event. It may also depend on the transmission method, and the difference in the information sending method does not change the gist of the present invention.

As described above in detail, according to the present invention, for example, in a remote monitoring system for electrical equipment, when the telephone on the side that sends the monitoring information (slave station side) is in use, the monitoring information can be transmitted. If there is no response from the receiving side (master station side), if the other party called by the slave station is not the master station and the other party answers, or even if it is the master station but the master station answers with its telephone, the slave station calls When the above-mentioned monitoring information transmitted from the station is not correctly received by the master station, the information to be transmitted is repeatedly sent and the subscriber telephone line is re-captured at each set time. Therefore, it is extremely rare that monitoring information that should be transmitted is not sent or incompletely transmitted, and even if such a situation occurs, a message to that effect will be displayed, so you can centrally monitor the electrical equipment that should be monitored. This invention is extremely useful for monitoring, and the present invention has extremely significant effects.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a remote electrical equipment monitoring system according to an embodiment of the present invention, FIG. 2 is a flowchart of the operation of the system shown in FIG. 1, and FIG. 3 is a diagram showing the format of transmitted information. (Main symbols) A...Slave station B...Master station C...Subscriber telephone switching network 1.2.3...Sensor 4...Transmitter 5...Telephone 41.42.43 ...Abnormality monitoring section 44...Control section 45...Storage section 46...
・Display section 48...Network control section 49...Abnormal alarm section procedure amendment 1. Display of 10.1 Showa Care'l! I The first part of the petition is I! ICI'l
Relationship with Application Person's name (name) 1i+';,, +Seii (4 agent residence Co., Ltd.) 2-6-2 Marunouchi, 2-6-2 Marunouchi, Cho-dai I11-ku, Tokyo 330, Shizusu Building --- 1- Amendment The following matters have been amended in the specification and drawings of the present application. 2. On the 4th line from the bottom of page 13, does it say "Because no abnormality information is output to 43D"? 1: "Because no abnormality information is output to 43D" ] Correct. 3. Correct the attached sheet for "Figure 1, Figure 3" in the drawing.

Claims (1)

[Scope of Claims] 1. In a system that sends monitoring information to a remote location using a telephone switched line network, a slave station installed on the side of equipment to be monitored that performs the following (A) to ( A monitoring information transmission method for a remote monitoring system that performs the control shown in F). (A) At the stage of transmitting monitoring information, it is determined whether the telephone line in which the slave station is accommodated is being used by a telephone installed for telephone calls, and if it is in use, it is determined for a set period of time. The above judgment is repeated to monitor whether the above telephone line becomes free, and when the above telephone line becomes free during the above set time, the said telephone line is captured, and the above mentioned telephone line becomes free during the above set time. (B) At the stage when the telephone line has been captured and the sending of the dialed number of the master station has been completed, (C) Control that determines whether or not there is a response from the master station within the set time, and releases the telephone line that is being captured if there is no response from the base station within the set time; (C) When the master station At the response stage, the master station sends an information transmission request signal (hereinafter referred to as ENQ signal) during the set time.
(D) At the stage when the monitoring information is sent to the master station , a control signal indicating complete reception of the reception confirmation signal from the master station (hereinafter referred to as A)
This is called a CK signal. ) or a control signal indicating incomplete reception (hereinafter referred to as a NAK signal),
When it is an ACK signal, the captured telephone line is released,
If it is a NAK signal, the above monitoring information is retransmitted and this operation is repeated. (E) In the control of (D) above, the number of times the above monitoring information is sent is counted and the counted value becomes the set value. (F) The number of times the telephone line is released under the control of CB), (C) and CE) above is cumulatively added, and the cumulative addition becomes the set value. Until then, the control of capturing the telephone line at set time intervals, calling the master station, and sending the monitoring information to the master station was repeated, and when the cumulative addition value reached the set value, the untransmitted display of the monitoring information was displayed. 2. Monitoring information transmission of the remote monitoring system according to claim 1, wherein the monitoring information sending control is started when the monitoring information changes. method. 3. Claim 1 in which the equipment to be monitored is electrical equipment
The monitoring information transmission method of the remote monitoring system described in .