JPH0116076B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a slave station abnormality detection method in a one-to-N polling type remote monitoring and control system in which all slave station abnormalities are detected by reducing the detection time.

The reality is that remote monitoring and control systems generally employ a polling method, which is a one-to-N peer control method. This is because in the case of a one-to-one control system, the more slave stations there are as controlled stations, the more transmission lines are required, and the control circuit of the master station, which is the control station, becomes enormous. In the polling method, the master station and slave stations are connected using a change activation method. In other words, each time a master station calls multiple slave stations one after another, the slave stations send responses to the master station one after another, but when a change in the status of a slave station occurs, the slave station The information is transmitted to the master station using a change-transmission method, and the master station reads information from the slave station preferentially by determining the information from the slave station.

In the polling-based remote monitoring and control system described above, the master station detects abnormalities in slave stations, but the conventional method has the disadvantage that it takes an unnecessarily long time to detect abnormalities in all slave stations. There is.

In other words, in a system where the transmission line is half-duplex, an abnormality in a slave station occurs when the master station calls the same slave station multiple times in a row, and if the slave station does not respond to these calls, the slave station It was detected as an abnormality and an alarm was displayed. This slave station abnormality detection method is adopted because in the polling method, the slave station cannot transmit a response to the master station unless the slave station paging signal is correctly received at the slave station, and also because the transmission line is half-duplex. If the transmission line is switched between the master station and the slave station, transmission line disconnection will inevitably occur. This is because line abnormalities cannot be detected as control congestion, control line disconnection, display congestion, or display circuit disconnection for each slave station. For example, if a control jam or control circuit disconnection occurs, the slave station cannot receive the slave station calling signal, so information about the control traffic jam or control circuit disconnection detected at the slave station cannot be sent to the master station. Therefore, abnormalities in the slave station are determined by checking whether there is no response to a calling signal from the master station. However, displaying an alarm just because a slave station abnormality has been detected in a single test may result in excessive alarms.
Generally, an alarm is displayed only when a slave station abnormality is detected three times in a row. Anomalies in slave stations are detected as described above, but it is clear that it takes a lot of time to perform anomaly tests on all slave stations. This means that all slave station abnormalities cannot be detected promptly.

An object of the present invention is to provide a slave station abnormality detection method that can quickly detect abnormalities in all slave stations.

For this purpose, the present invention focuses on the fact that the probability that all slave stations become abnormal at the same time is smaller as the number of slave stations increases.
The master station sends a paging signal to all slave stations one time (1
If there is no response to the call from any of the slave stations to the master station, the master station detects it as an abnormality in all the slave stations (common abnormality). That is, detection of an abnormality in a slave station begins by determining whether or not all slave stations are abnormal, and if all slave stations are not abnormal at the same time, the conventional abnormality detection for each slave station is performed for the first time.

The present invention will be explained below with reference to FIGS. 1 to 4.

First, FIG. 1 shows the general configuration of a master station according to the present invention. As shown in the figure, a slave station calling circuit 1, a transmitting circuit 2, a receiving circuit 3, and a calling slave station reply verification circuit 4 are shown, and only the main parts related to the present invention are extracted. According to this, slave station calling circuit 1
The slave station calling signal from the slave station is transmitted onto the transmission line via the transmitting circuit 2, while the response or reply from the slave station to the calling signal is received by the receiving circuit 3 via the transmission line and then sent to the called slave station. Reply verification circuit 4
This is done in such a way that it is verified by That is,
The calling slave station reply verification circuit 4 detects the presence or absence of a response at the verification timing from the slave station calling circuit 1, and outputs an abnormal signal for all slave stations and a slave station abnormal signal for the slave stations depending on the verification result. is configured to do so.

FIG. 2 shows details of an example of the calling slave station reply verification circuit 4 together with the configuration of the slave station.
As shown in the figure, all n slave stations B have the same configuration,
It can be connected in parallel to the downlink and uplink transmission lines 5 and 6. During the abnormality test, a calling signal including a device address is transmitted on the downlink transmission line 5, and only the slave stations that match the device address are connected to the uplink transmission line 6 and transmit a response to the master station A. ing. That is, under normal conditions, when the transmission/reception control circuit 8 of the slave station B recognizes that the device address received by the receiving circuit 7 is unique to its own station, the transmission switching circuit 10 is closed and the slave station B does not transmit. A response to a call from circuit 9 is transmitted to master station A.

However, if some kind of abnormality occurs in the transmission lines 5, 6 or the slave station, the receiving circuit 3 in the master station A will be damaged as a result.
It is clear that the mobile station cannot receive a response or a reply regardless of whether a response or reply is actually transmitted from the slave station. Therefore, if the calling slave station reply verification circuit 4 verifies the presence or absence of a response, an abnormality in the slave station can be detected. This test is performed by determining whether or not there is a response from the slave station related to the call within a certain amount of time from the sending of the paging signal, but conventionally, the slave station abnormality was established for the slave station. This was detected by the counter 4b and the slave station abnormality storage/display circuit 4c. That is,
Counter 4b and slave station abnormality memory/display circuit 4c
is reset by the response presence detection signal from the called slave station response presence/absence detection circuit 4a, and the slave station abnormality memory/display circuit 4c is reset by the response no detection signal outputted from the called slave station response presence/absence detection circuit 4a by the counter 4b. It is set when a certain number (usually a value of 3) is counted consecutively. Although this makes it possible to detect abnormalities in individual slave stations, the present invention detects abnormalities in all slave stations by adding some circuits to the calling slave station reply verification circuit 4 configured as described above. It is.

In this example, the conventional called slave station reply verification circuit 4 is provided with an all slave station response non-detection circuit 4d, an AND gate 4e, and an all slave station abnormality storage/display circuit 4f, thereby detecting all slave station abnormalities. That is, if the all slave station response non-response detection circuit 4d is set by the calling signal for the first slave station from the slave station calling circuit 1 and reset by the response presence detection signal, the circuits 4d are sequentially called. If there is no response from any of the slave stations, the all slave station response non-detection circuit 4d will not be reset. Therefore, the state of the all slave station response non-detection circuit 4d is stored in the all slave station abnormal memory/display circuit 4f via the AND gate 4e at a timing slightly later than the verification timing for the nth slave station. Therefore, it is detected whether all the slave stations are abnormal or not. That is, when the all slave station abnormality storage/display circuit 4f is in the set state, it can be determined that all the slave stations are abnormal, and when it is in the reset state, at least one of the slave stations can be determined to be normal. It is. Therefore, when in the reset state, abnormality detection for each slave station is performed as in the past. Incidentally, when the all slave station abnormality storage/display circuit 4f is placed in the set state, that state is reset by the first response detection signal thereafter.

Figures 3 and 4 show operation time charts to supplement the above explanation. Figure 3 shows the case when all slave stations are normal, and Figure 4 shows the case when all slave stations are abnormal. shows. As is clear from FIG. 4, it can be seen that all slave station abnormalities are quickly detected according to the present invention. Although Fig. 4 shows a case in which calls are made multiple times to all slave stations, in general, when all slave station abnormalities are detected, subsequent calls are made to the slave stations. It can be said that it is unnecessary to make a call for this purpose.

Although the present invention is as described above, the present invention is applicable not only when the transmission line is half-duplexed but also when it is duplexed.

As explained above, in the present invention, prior to detecting an abnormality in each slave station, which requires a lot of time, the master station calls the slave station once and then repeats the same calling procedure to the slave stations. By performing this sequentially, the master station can detect that an abnormality has occurred in all slave stations at the same time. Therefore, the present invention has the advantage that all slave station abnormalities are detected more quickly than the conventional method.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a general configuration of a master station according to the present invention, FIG. 2 is a diagram showing details of an example of a calling slave station reply verification circuit in the master station together with the configuration of a slave station, and FIG. , and FIG. 4 are diagrams showing operation time charts for supplementary explanation of the present invention. A...Master station, B...Slave station, 1...Slave station calling circuit, 2...Sending circuit, 3...Receiving circuit, 4...Calling slave station reply verification circuit, 4a...Calling slave station response presence/absence Detection circuit, 4b...Counter, 4c...Slave station abnormality memory/display circuit, 4d...All slave station response no detection circuit, 4f...All slave station abnormality memory/display circuit.

Claims (1)

[Claims] 1. In a remote monitoring and control system using a one-to-N polling system, in which the slave station returns a response to the call to the master station in response to sequential calls from the master station to the N slave stations, the master station calls the N slave stations from the master station. If there is no response from any slave station in one paging cycle that finishes polling sequentially, it is detected as a common abnormality, and if there is no common abnormality, the call is answered only from a specific slave station in multiple paging cycles. A slave station abnormality detection method in a remote monitoring and control system, characterized in that an individual abnormality in the particular slave station is detected on the condition that there is no continuous response.