JPH0241058A - Diagnostic device for data transmission system - Google Patents

Abstract

PURPOSE:To easily specify a fault location by adding a simple diagnostic section to a terminal equipment without health check. CONSTITUTION:A DC branch section 13 of a simple diagnostic section 12 branches a signal on a transmission line and sends it to a detection section 14. The detection section 14 checks H, L of the set level and detects a signal or noise, a watchdog timer 15 is started. The timer 15 raises an alarm if a reception signal RD or a reply signal SD is not detected within a prescribed time. In this case, if the system is normal, at least one SD or RD exists before the timer 15 expires, no alarm is raised. However, if the transmission is stopped due to a fault of the application software, no replay exists and the timer 15 expires and an alarm is raised.

Description

[Detailed Description of the Invention] [Summary of the Invention] Regarding a diagnostic device for a data transmission system,
The purpose is to provide a diagnostic method that can detect abnormalities in both software states.In a diagnostic method for a data transmission system in which a center device and multiple terminal devices are connected by a transmission line, the device is powered on and communicates between the devices. H2L when possible
Means for monitoring a signal that takes one level and takes the other level when communication is impossible and outputs an alarm when the signal takes the other level, and means for detecting transmitted and received signals on the transmission line. Then, the terminal device is configured to include a simple diagnostic section including means for outputting an alarm when the means does not detect a transmitted or received signal within the monitoring time.

[Industrial application field]

The present invention relates to a diagnostic device for a data transmission system, and more particularly to a diagnostic device for simultaneously and easily monitoring abnormalities in both hardware and software between data terminals.

If reception becomes impossible on the receiving side due to a line problem between the sending side and the receiving side or a problem with the sending side device, it is necessary to promptly detect this state and perform recovery work.

[Conventional technology]

In a data transmission system that includes a center device and data terminal devices (generally multiple) as shown in Figure 5, if H and L of the data ready (DR) line are checked, and L (low), a warning light is activated. I am trying to display it. DR is H (high) if the device is powered on and communication is possible;
This indicates a hardware failure in which communication is not possible due to the device power being disconnected or the transmission line being disconnected. Note that FIG. 5 shows the case of unilateral transmission from the center to the terminal, where the transmission device is specifically a modem, and the transmission line is a dedicated line, a public line, or a combination thereof.

Even if data ready is H, it does not necessarily mean that communication is normal. For example, even if the power is on, if the application software does not run due to some kind of failure, no communication will take place. In order to deal with such software abnormalities, a health check is sometimes provided. This is firmware that constantly checks, for example, whether polling signals are arriving normally or whether responses to transmission requests are coming normally.

[Problem to be solved by the invention] Conventionally, monitoring between opposing devices has mainly been between lines including transmission devices (DR method), and monitoring has been performed mainly between lines including transmission devices (DR method), and monitoring has been performed from software troubles excluding abnormalities such as equipment power outage. In order to detect defects in transmission conditions such as processing stoppages, dedicated software (health check) is used to establish a transmission diagnostic procedure between the sending side and the receiving side, which is always waiting to receive information.
It was necessary to prepare.

However, there are many types of terminals, and there are also existing products, so not all terminals are equipped with a self-diagnosis function (dedicated software mentioned above), and for this reason, there may be cases where no notification (announcement) is made in the event of an abnormality. be. This poses a problem in that it is difficult to identify the location of the failure, and the problem is that it is left to the judgment of the operator and the results of trial-and-error tests.

The main body of end-to-end (END-TO-END) confirmation and equipment/line monitoring used in conventional network management is only to check whether there is a problem on the line, and the terminal side Under the circumstances where it cannot be said that an automatic diagnosis function is necessarily added to a terminal or a parent device, it is desired to develop a method that can easily perform trouble confirmation analysis including software processing of the opposing device as seen from the terminal or parent device.

An object of the present invention is to provide a diagnostic method that can easily detect abnormalities in both hardware and software, particularly on the terminal side.

[Means to solve the problem]

As shown in FIG. 1, in the present invention, a terminal device 10 is provided with a simplified diagnostic section 12. Reference numeral 11 denotes a data terminal, which is the main body of the terminal device 10. Reference numeral 20 denotes a center device, which is generally connected to a large number of terminal devices IO through transmission lines. The dedicated software (health check) is usually included in the center device, so the simple diagnostic section 12 does not need to be provided in the center device.

FIG. 2 shows the configuration of the simple diagnostic section 12. 13 is a DC branch section, 14 is an H/L level detection section, and 15 is a monitoring timer.

[Effect]

The DC branching section 13 of the simple diagnosis section 12 branches the signal on the transmission line and sends it to the detection section 14 . This signal is a receiving signal (RD in the case of R5232C) at a level that changes in detail.
In addition to the response signal (SD), noise is also included. The detection unit 14 checks the sent levels H and L, and starts the monitoring timer 15 when the above signal or noise is detected. The monitoring timer 15 times out after a predetermined period of time, for example 15 seconds, and outputs an alarm if no SD or RD is detected within this 15 seconds.

The above-mentioned predetermined time is the period or interval of SD or RD plus an appropriate margin α, and is a period in which there should normally be at least one SD or RD within this predetermined time. Therefore, if it is normal, there will be at least one SD or RD before the monitoring timer 15 times out, and the timer will be reset and start counting again, so no alarm will be output. However, if the transmission stops due to an abnormality in the application software mentioned above, there will be no response.
The timer 15 times out and an alarm is announced to the center device 20 and the like.

If such a simple diagnostic unit 12 is provided independently and attached to a terminal that does not have a health check, it can be found that a soft error has occurred on the transmission line of the terminal, which is effective in identifying the location of the failure. . Also, data ready DR H,
Since the abnormality alarm function by L is on each terminal, the alarm is DR.
It is possible to distinguish whether the fault is a hardware fault or a software fault, depending on whether the fault is from the diagnostic unit 12 or from the diagnostic unit 12.

〔Example〕

FIG. 3 shows an embodiment of the present invention. In the same figure (a), 10 is a terminal device, 11 is its main body, 12 is a simple diagnostic unit, 18
is a modem. Further, 2o is a center device, and L is a transmission line. The same figure (b) shows the structure of the simple type diagnosis part 12, and 1
3 is a branching section, 16 is a disconnection detection section, 14 is a level detection section, 1
5 is a monitoring timer.

The operation will be explained with reference to the time chart in FIG.
When becomes L, an output is generated and becomes an alarm output from the monitoring timer 15 (Case 1).

In the conventional device, this simply turns on the lamp, but in the present invention, an announcement is made to the center device or the like.

Next, the level detection section 14 detects the presence or absence of SD/RD, but this is only effective if the detection result is within the monitoring time (15 seconds) of the timer 15. When the terminal is powered on at time t0, monitoring begins, but since it is unstable at first, it is masked for a certain period of time T. The timer starts at the first SD/SD after power-on.
It starts with RD or noise and then enters the monitoring period after T. If there is no SD/RD within the monitoring period T2, the monitoring timer 15 generates an alarm output and makes an announcement to the center device, etc. (Case 2).

If SD/RD is detected within the monitoring time T2, the timer 15 is reset and no alarm output occurs. Timer reset (R
), the timer is set again (S), the timer starts counting again, and the check to see if there is SD/RD within the time Tz is restarted. The same applies below.

Checking whether SD/RD is present within the monitoring period T2 is performed using a clock synchronized with SD/RD. Areas other than those in the vicinity of this clock are masked, and the level in the vicinity of the clock is monitored, and if it is equal to or higher than the dark value, it is determined to be SD/RD, thereby separating noise and signals. This clock is not used for level detection for timer start.
If the level simply becomes higher than the threshold, it is determined that there is a signal.

Therefore, this detection result indicates SD/RD or noise.

In this example, the maximum value of the period of SD and RD is 10 seconds, and a tolerance value of 50% is added to this to make 15 seconds, which is taken as the monitoring time.

〔Effect of the invention〕

As explained above, according to the present invention, it is easy to identify failures even when various failure events occur at short intervals in a network, and it is also effective in the fields of network configuration management and operation management. It greatly contributes to management work.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the principle of the present invention, Fig. 2 is a detailed explanatory diagram of a part of Fig. 1, Fig. 3 is a block diagram showing an embodiment of the present invention, and Fig. 4 is an explanation of the operation of Fig. 3. FIG. 5 is an explanatory diagram of a conventional example. In FIGS. 1 and 2, 10 is a terminal device, 12 is a simple diagnostic section, 20 is a center device, L is a transmission line, 14 is a level detector, and 15 is a monitoring timer. An explanatory diagram of the principle of the present invention. Fig. 1. A detailed explanatory diagram of a part of Fig. 1. An explanatory diagram of a conventional example. Fig. 5.

Claims (1)

[Claims] 1. In a diagnostic method for a data transmission system in which a center device (20) and a plurality of terminal devices (10) are connected by a transmission line (L), the devices are powered on and communication is possible between the devices. means (16, 15) for monitoring a signal (DR) which takes one of the H and L levels when communication is impossible and takes the other level when communication is impossible, and outputs an alarm when the signal takes the other level. Also, means (14) for detecting the transmitted and received signals (SD, RD) on the transmission line, and means (15) for outputting an alarm when the means (14) does not detect the transmitted and received signals within the monitoring time. A diagnostic device for a data transmission system, characterized in that a simple diagnostic section (12) is provided in a terminal device (10).