JPH02217039A - Poling/selecting control procedure system - Google Patents

Abstract

PURPOSE:To reduce the generation of unnecessary poling and to improve a line using ratio and system operating efficiency by allowing a master station side to automatically recognize no generation of information to be transmitted to the master station for a long time and executing slow poling processing. CONSTITUTION:The exsistence of information transmission from slave stations 42, 43 in response to poling from the master station 40 is monitored between the master station 40 and respective slave stations 42, 43 for mutually transmitting information on a network connected through a branch communication line 41, and when information transmission from the same slave station is not continuously executed, the state is counted up. When the counted result reaches a specific value, the time interval up to the execution of poling is switched to another previously specified interval value. When information is transmitted from the slave station concerned thereafter, the switched interval value is restored to the original interval value to execute poling. Consequently, unnecessary poling can be reduced and the system efficiency and the network using efficiency can be improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a control method for transmitting information (data) online over a branch communication network, particularly a polling/selecting control procedure method. .

[Conventional technology]

The polling/serenoting control procedure method is based on a combination of polling, in which the master station on a branched communication line invites the slave stations to send information, and selecting, which accepts and confirms the information transmission from the master station. It is a control procedure method.

Of these, polling in particular is conventionally used when the slave station has no information to send, in response to a solicitation from the master station.
Abandon sequence each time (a pattern code set in advance to notify the main station that there is no information to send)
This is done through the procedure of returning the item.

When there are a plurality of slave stations, the master station polls each slave station at fixed time intervals in a preset priority order.

With this method, even if information to be sent to a slave station does not occur for a long time, the master station polls the slave station at a predetermined time interval, and in response, an abandonment sequence is returned. will be repeated.

In the prior art, in response to polling from a master station to a slave station, if a particular slave station does not generate any information to be transmitted for a long period of time, an abandonment sequence is always returned in response to polling at regular intervals.

If the slave station does not have the environment and other conditions to support polling (for example, the device itself is not powered on, or the device has not been started up according to the operating procedures) , the slave station cannot return an abandonment sequence in response to polling from the master station. In this case, the main station performs a so-called slow polling process in which it detects whether or not a response to polling has been received from the relevant slave station and resets the time interval for the next polling of the relevant slave station to be larger than the normal interval. This generally reduces unnecessary polling as much as possible so as not to reduce system efficiency or network usage efficiency.

[The invention attempts to solve the problem. ? ! ! Subject: However,
In the conventional technology described above, operational preparations are made on the slave station side, and in the above case where information to be transmitted to the master station does not occur for a long time, unnecessary transmission from the master station to the slave station is required. A polling sequence and a corresponding abandonment sequence are transmitted over the communication line. This has the disadvantage that line usage efficiency is low, and unnecessary polling results in connections using branch lines, which delays the time to poll other slave stations that have transmitted information. However, the disadvantage is that the so-called system operational efficiency is also lowered.

[Means to solve the problem]

The configuration of the polling/selecting control procedure system of the present invention is such that a polling/selecting procedure is used between a master station and each slave station to mutually transmit information (data) on a network connected by a branch communication line. means for monitoring the presence or absence of information transmission to said slave station in response to polling from the station; means for counting when there is no continuous information transmission from the same slave station; means for polling the slave station by switching the time interval until the next time it polls the slave station to another interval value specified in advance; The present invention is characterized in that it includes means for returning the time interval before polling the slave station to the original interval value specified in advance and polling the slave station.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block flow chart showing one embodiment of the present invention, and FIG. 2 is a polling table P shown in FIG.
Figure 3 is a diagram for explaining the contents of the OLT, and Figure 4 is a time chart of reception of an abandonment sequence for polling.
The figure is a connection diagram of the master station and each slave station on the branch communication line, and FIG. 5 is a time chart 1 to 1 of reception of an abandonment sequence for conventional polling.

As shown in FIG. 5, in an example where a master station 40 and a plurality of slave stations 42 are connected via a branch communication line 41, in order to perform a bolink from the master station 40 to each slave station 42, first, each slave station Reference is made to the polling table POLT in which information for each is stored.

The master station side generates a polling sequence based on the slave station address (ADR8 in Figure 5) according to the polling order shown in the polling table POLT (POLNO in Figure 2), and transmits it to the polling transmitter 1 for the corresponding slave station.
Send by.

Thereafter, the polling response monitoring means 2 time-monitors the response from each slave station to the polling using the response time monitoring value (RPTMR in FIG. 2). The content of the take sent from each slave station within the monitoring time is compared with the abandonment sequence code (ABSEQ in Figure 2), and if it is not equal to the abandonment sequence code 1~, it is determined that information has been received, and the corresponding slave station In order to reset the processing related to slow polling, the slow polling processing reset means initializes the abandoned Siegen continuous reception counter (ACCNT in Fig. 2) and the slow polling flag (5LOWF in Fig. 2) in the polling table (POLT), and Process the received information.

When the response from the relevant slave station to the relevant polling is an abandonment sequence code (ABSEQ in FIG. 2), the relevant slave station abandonment sequence continuous reception determining means 6 makes a determination regarding the slow polling process for the relevant slave station. Referring to the polling table (POLT), it is first determined whether slow polling is already in progress based on the state of the slow polling flag (5LOWF in FIG. 2), and if the flag is set, the polling interval monitoring means 8
Execute. Also, if the flag is not set,
Abandonment sequence continuous reception counter (Figure 2 ACCNT)
is updated, and it is determined whether the counter value is equal to the specified value of the number of consecutive receptions of the abandoned sequence. If they are not equal, the polling inquiry means 8 is executed. If they are equal, do the following to set processing related to slow polling.

The slow polling flag (LOWF in FIG. 2, 5) in the polling table (POLT) for the relevant slave station is set, and the polling interval monitoring means 8 is executed.

The polling interval monitoring means 8
Determine the slow polling flag (5LOWF in Figure 2) for the corresponding slave station in the table (POL T ), and if the flag is not set, the normal polling flag is determined.
The polling interval is timed using the interval value (NPINT in FIG. 2).

FIG. 3 shows the sequence described above.

〔Effect of the invention〕

As explained above, in the slave station on the branch line controlled by the polling control method, when information to be transmitted to the master station does not occur for a relatively long time, the master station automatically sends information to the master station. recognition and slow polling (
By increasing the polling time interval of the corresponding slave station l\, the occurrence of unnecessary polling can be minimized, thereby increasing the line usage rate and system operation efficiency.

Monitoring means, 4. Slow polling processing reset means, 5. Reception information processing means, 6. Applicable slave abandonment sequence continuous reception determination means, 7. Slow polling processing setting means, 38. Polling interval. Surveillance means.

Claims (1)

[Claims] On a network connected by a branch communication line, a polling/selecting procedure is used between a master station and each slave station that transmit information (data) to each other, in response to polling from the master station. means for monitoring the presence or absence of information; means for counting when there is no continuous information transmission from the same slave station; Means for polling by switching the time interval to another pre-specified interval value, and a time interval for polling the slave station next time when information is transmitted from the slave station. 1. A polling/selecting control procedure method, comprising means for returning polling to an original interval value specified in advance.