JPH03198549A - Multi-point monitor system - Google Patents

Abstract

PURPOSE:To collect slave station information efficiently by providing two queues as a normal slave station queue and a fault slave station queue and integrating a slave station table into the normal slave station queue when a slave station gives consecutively no reply and a reply comes to the fault slave station queue with respect to a polling from a master station. CONSTITUTION:A management means 13 of a master station 1 extracts a slave station table 9 of a fault slave station queue 12 once per n-time of polling a normal slave station queue 11 and sends the result to a transmission reception means 8. The transmission reception means 8 based on the slave station table 9 sends a polling frame 7 being a transmission invitation added with a relevant slave station address to a transmission line 6. When normal reply comes from the relevant slave station, the management means 13 returns no response number of times of the slave station table 9 to zero, revises slave station information to integrate the slave station table 9 to the normal slave station queue 11. When the relevant slave station gives no reply and number of times of no reply of the slave station table 9 is (m), the slave station table 9 is integrated into the fault slave station queue 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multi-point monitoring system in which the flow of data is centrally controlled by one master station (control station).

[Prior Art] Figure 3 shows the conventional polling system shown in, for example, "Microcomputer Interface Technical Report, Texts [1] to (5) JP, 13 () - Rikepps Publishing Co., Ltd., April 27, 1980)". It is an explanatory diagram showing a multi-point monitoring system using a selection method (send invitation reception request method). In the figure, 1 is a master station as a specific station (control station), 2 to 5 are slave stations, The master station 1 is connected to the slave stations 2 to 5 in a multipoint manner and performs communication.The master station 1 stores and manages the slave station table 9 corresponding to the slave stations 2 to 5 in a queue 10, and The station table 9 is retrieved and loaded into the transmitting/receiving means 8, and a polling frame 7, which is an invitation to send to which the corresponding slave station address is added, is sent to the transmission path 6.The slave stations 2 to 5 respond in accordance with the invitation to send their own address. The frame is sent back to master station 1.

Next, the operation will be explained. First, the master station 1 sequentially takes out the slave station tables 9 from the queue 10 and transfers them to the transmitting/receiving means 8. The transmitting/receiving means 8 transmits a polling frame 7 inviting transmission to the transmission path 6 according to the slave station address in the slave station table 9. Transmission path 6 has slave stations 2 to 2 in multi-point form.
5 is connected, the polling frame 7 is intercepted by all the slave stations, but the polling frame 7 is captured only by the slave stations whose slave station addresses match, and only the slave stations in question add slave station information. The received response frame is sent back to the master station 1 via the transmission line 6. When the transmitting/receiving means 8 of the master station 1 receives a response frame from the corresponding slave station through the above operation, it updates the slave station information in the slave station table 9 and stores it in the queue 10. The master station 1 sequentially updates the queue 10 (by performing processing, it sequentially collects the slave station information of the slave stations 2 to 5).

[Problem to be solved by the invention]

Conventional multipoint monitoring systems are configured as described above, so even if a faulty slave station among multiple slave stations that does not return a response frame to the master station occurs, it will not be removed from the queue. , there were problems such as a timeout occurring at the faulty slave station during each polling, the polling cycle of the master station becoming longer, and information update of normal slave stations being delayed.

This invention was made in order to solve the above-mentioned problems, and it is a multi-point system that does not delay the information update of normal slave stations even when a failed slave station occurs or when the failed slave station is restored. The purpose is to obtain a monitoring system.

Means for Solving Problem C] The multi-point monitoring system according to the present invention provides a normal slave station queue and a failed slave station queue in a master station, and a slave station table corresponding to a slave station table in the normal slave station queue. When a predetermined number of slave stations are polled, the slave stations corresponding to the slave station table in the failed slave station queue are polled, and if the slave stations are normal or have no continuous response below the specified number, If so, the slave station table corresponding to that slave station is added to the normal slave station queue, and if the slave station does not respond continuously beyond the specified number of slots, the slave station corresponding to that slave station is added to the failed slave station queue. A management means for incorporating a slave station table is provided.

r Effect] The master station in the present invention has two queues, a normal slave station queue and a failed slave station queue, and when a slave station continuously fails to respond to polling from the master station. will be added to the disabled child station queue.

Also, each time the normal slave station queue is processed for a predetermined number of cycles, the faulty slave station queue is processed for one station, and if there is a response, the slave station table of that slave station is incorporated into the normal slave station queue. By doing so, slave station information can be collected efficiently.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same parts as in FIG. 3 are indicated by the same reference numerals. In FIG. Stations 2-5
It has a management means 13 for storing and managing the child station table 9 corresponding to the child station in each of the queues. In addition, the management means 13 takes out the slave station table 9 according to the conditions, transfers it to the transmitting/receiving means 8, and causes the polling frame 7, which is an invitation to send, to which the corresponding slave station address is added, to be transmitted to the transmission path 6.

Next, the operation will be explained. First, the master station 1 starts with the slave station 2.
All the slave station tables 9 of ~5 are stored in the normal slave station queue 11 (.The slave station table 9 includes, for example, the slave station address, the number of non-responses, the slave station information, etc. (step 5TI), and takes out the management code 9 of the master station 1 once and sends it to the transmitting/receiving means 8 (step 5T2). Transmitting/receiving means 8
transmits the polling frame 7, which is an invitation to send, to which the corresponding slave station address is added based on the slave station table 9, to the transmission line 6 (step 5T3). Here, if there is a normal response from the corresponding slave station, the management means 13 sends the slave station table 9
The number of non-responses is returned to zero, the slave station information is updated, and the slave station table 9 is added to the normal slave station queue 11 (step 5).
T4). Furthermore, if the corresponding slave station does not respond and the number of non-responses in the slave station table 9 is m, the slave station table 9 is added to the failed slave station queue 12 (step 5T).
5). If the corresponding slave station does not respond and the number of non-responses in the slave station table 9 is less than m times, 1 is added to the number of non-responses and the slave station is added to the normal slave station queue 11 (step 5T6).
. Note that a determination of no response is made by not receiving a response frame from the slave station within a certain period of time after transmitting the polling frame 7.

Further, in the above embodiment, an example was explained in which two queues were provided, a normal slave station queue and a failed slave station queue, but the queues may be divided into a plurality of stages depending on the purpose.

Further, the setting values of the conditions for transfer and the values of the respective numbers m and n may be changed depending on the purpose (the same effect as in the above embodiment is achieved).

〔Effect of the invention〕

As described above, according to the present invention, a normal slave station queue and a failed slave station queue are provided in the master station, and the slave stations respond to the polling from the master station with successive non-responses according to the slave station table. Every time 0 slave stations are polled, one slave station corresponding to the slave station table in the failed slave station queue is polled, and if there is a response, the slave station table of that slave station is added to the normal slave station queue. This has the effect of reducing the polling frequency of disabled child stations and allowing efficient collection of information on child stations.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a multi-point monitoring system according to an embodiment of the present invention, FIG. 2 is a flowchart for explaining the operation of FIG. 1, and FIG. 3 is an explanatory diagram of a conventional multi-point monitoring system. be. In the figure, 1 is a master station, 2 to 5 are slave stations, 7 is a polling frame, 8 is a transmitting/receiving means, 9 is a slave station table, 11 is a normal slave station queue, 12 is a failed slave station queue, and 13 is a management It is a means. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In a multi-point monitoring system in which a master station sequentially polls multiple slave stations to collect slave station information, the slave station waits for a normal slave station in which a slave station table containing the addresses of the slave stations, the number of non-responses, and slave station information is stored. a faulty slave station queue in which the slave station tables of slave stations that have not responded to polling consecutively for more than a specified number of times are sequentially stored; and a slave station table extracted from the normal slave station queue. , sequentially transfer the polling frame to the transmitting/receiving means and transmit the polling frame, and when a predetermined number of slave station tables are taken out from the normal slave station queue, one slave station table is taken out from the failed slave station queue and the polling frame is transmitted. If the slave station to which the polling frame is transmitted responds, or if the slave station does not respond and the number of non-responses is equal to or less than the specified number of times, the normal slave station queue A slave station table corresponding to this slave station is incorporated into the slave station, and if the slave station does not respond and the number of times of no response exceeds the specified number of times, the slave station corresponding to this slave station is added to the failed slave station queue. A multi-point monitoring system characterized in that a master station is provided with a management means for incorporating tables.