JPH0349441A - Collection system for monitor data - Google Patents

Abstract

PURPOSE:To reduce the standby time of a slave station at the time of polling by collecting a data while using the 3 modes and an idle time of polling so as to allow the system to cope with a change in a monitor data. CONSTITUTION:When a monitor data such as state of various installation or various measurements in plural slave stations is collected by one master station via a data transmission line, 3 kinds of the transmission command modes are provided and the master station uses the 3 kinds of commands and uses the 3 modes to allow a slave station whose monitor data is subject to change to send automonously the data based on the setting of a timer sequentially through the use of an idle time of the polling period. The setting of the timer is made minute in such a way, then a slave station whose monitor data is subject to change sends the data automonously at an optional point of time substantially, and the waiting time is reduced.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for collecting monitoring data of a plurality of slave stations with one master station, it is an object of the present invention to provide a monitoring data collection method that reduces the waiting time of slave stations during polling. The first mode is to poll all slave stations sequentially within a predetermined cycle and collect monitoring data of the slave stations, and when the polling within the cycle has completed, the master station polls each slave station. A spontaneous data transmission command is given, and each slave station, upon receiving the spontaneous data transmission command, detects a change in data before the expiration of the timer time allocated to start monitoring data transmission during the idle time until the next polling. A second mode in which only one slave station preferentially and spontaneously starts transmitting monitoring data while other slave stations are prohibited from transmitting, and when the transmission of supervisory data in the second mode is completed. A third mode in which the same spontaneous data transmission command as in the second mode is given from the master station to each slave station, and a transmission prohibition command for the slave station whose transmission has been completed is included only once in the spontaneous data transmission command. Construct. [Industrial Field of Application] The present invention relates to a method for collecting monitoring data, and in particular to a method for collecting monitoring data from a plurality of slave stations using one master station, and further relates to a method for collecting monitoring data from a plurality of slave stations, and further relates to a method for collecting monitor data from a plurality of slave stations, and further relates to a method for collecting monitor data from a plurality of slave stations, and further relates to a method for collecting surveillance data from a plurality of slave stations. This relates to a method for one master station to collect monitoring data, such as measured values, via a data transmission line. With the recent increase in the scale of remote monitoring systems and the increase in the amount of monitoring data generated, there is a need to reduce the time required to collect data as much as possible, especially when the content of monitoring data changes. It is necessary to know what has changed as soon as possible and to respond quickly to the change. For this reason, a polling method with a high transmission rate is adopted, but as shown in Figure 5, a master station sends multiple slave stations 1 to
Since data is collected by specifying N one station at a time in order, as the number of slave stations increases, the time required to collect data becomes longer.In such cases, the data collection time can be shortened. has become an urgent need. [Prior Art] In order to shorten the data collection time in the well-known polling method as shown in FIG. In this mode, monitor data is determined in advance,
If there is no change in the monitoring data, 1/M (l as shown in the figure) of all data (D1 to D in the figure) during one polling.
/5). In this mode, all the data of one slave station can be collected by polling M times, and if there is a change in the monitoring data during that time, all the data of the slave station can be collected by polling M times. I am trying to transmit the following. [Problem to be solved by the invention] In the conventional example shown in Fig. 6, changed monitoring data can be collected more quickly than the method in which each slave station sends all data each time. Everyone has to wait until the corresponding slave station's turn comes, and the blank time during which the slave station waits for its own turn becomes a bigger problem as the number of slave stations increases. becomes. Therefore, an object of the present invention is to provide a monitoring data collection method that reduces the waiting time of a slave station during polling. [Means and effects for solving the problem] In order to achieve the above object, the monitoring data collection method according to the present invention:
There are three types of transmission command modes, and the master station transmits these three types of commands, using them as shown below. Each slave station identifies these three types of transmission commands and transmits data or suspends transmission according to the contents of the command. This will be explained below with reference to FIGS. 1 and 2. Ω plan 17) -11-U 1 (
A mode in which all slave stations are polled sequentially within a predetermined cycle to collect monitoring data of the slave stations): In this mode, the first step is the same as the conventional polling method, but the second step is It does not change, and the second polling is performed after a predetermined period has passed. Therefore, even if there is no change in the monitoring data, the monitoring data of all slave stations will be updated at the master station at a predetermined period. Therefore, there is a predetermined polling pause period within each cycle, and the second mode and the third mode are executed during this period. The reason why the first mode is necessary is as follows. a) Immediately after the power is turned on at the Il station, data is not collected from the slave stations, so it is necessary to collect and store all data from all stations. b) When a slave station turns off its power and restarts after a while, the monitoring data may have changed, so it is necessary to collect the data of that slave station. c) Since the data transmission line between the master station and the slave station may be temporarily interrupted and some data may be lost, all data must be periodically collected and old data stored. It is necessary to update the . Engineering) When the transmission function of a slave station malfunctions and data cannot be transmitted, it is easy to detect the failure because it becomes clear that there is no response from the slave station (=no-response alarm). Alliance 1st raw ball 2nd craft (when the polling within the cycle has completed one round,
A spontaneous data transmission command is given from the master station to each slave station, and each slave station shifts from each other to start monitoring data transmission during the idle time from receiving the spontaneous data transmission command to each slave station ring. mode in which only one slave station whose data has changed before the end of the allocated timer time starts transmitting monitoring data preferentially and spontaneously, and other slave stations are prohibited from transmitting data): In this mode, the first During the free time from immediately after the polling in mode 1 is completed until immediately before the next polling, a spontaneous data transmission command M2 is repeatedly transmitted from the master station to each slave station as shown in FIG. From this point on, each slave station that receives this spontaneous data command M2 at the same time allocates a slightly shifted timer time to each slave station during the above-mentioned free time, as shown in Figure 2. If there is a change in the monitoring data, the slave station will preferentially and spontaneously start transmitting the monitoring data when the allocated timer time expires, and if other slave stations are intercepting the monitoring data, they will not be able to transmit it. It is prohibited. In the example of FIG. 1, among the slave stations 1 and 3 whose monitoring data changed at the time of the third command M2, the slave station 1 preferentially transmits the data DI to the master station.
When the slave station 3 receives the data Di at the same time as the master station, it enters a transmission prohibited state.The transmission prohibition is canceled when it receives a spontaneous data transmission command from the master station. In this way, in the second mode, the timer time settings can be divided into small sections for each slave station, so it is not actually necessary to specify the slave station, and instead it is possible to set the timer time setting for each slave station in detail. This is equivalent to the command "Send it back." Ω Strategy 1 Summer i 2nd (When the transmission of monitoring data in the second mode is completed, the master station gives the same spontaneous data sending command as in the second mode to each slave station, and during the spontaneous data sending command In the second mode, a slave station with a high transmission priority has the right to always transmit before other slave stations by setting the timer. Therefore, in a case where monitoring data changes frequently in a slave station with a high priority, a slave station with a low priority will be unable to transmit data no matter how long it takes. The third mode is a mode to avoid this, and the master station that received the data DI from slave station 1 during the third command M2 switches to the third mode and finishes receiving the data DI. At this point, the command M3 shown in Figure 1 is sent to each slave station. That is, the command M3-1 includes a transmission prohibition command and prohibits transmission to the slave station l, regardless of whether there is a change in the monitoring data. In other respects, this command M3-1 is the command M
2, the slave station 3 that has changed at this point starts transmitting the monitoring data D3 after the timer time expires.

The master station, which has finished receiving the monitoring data D3 of the slave station 3, issues a transmission prohibition command to the slave station 3 in the next command M3-3 in the same way. If there is no data change in any slave station according to the command M3-3, and if there is free time before the next polling, the mode returns from the third mode to the second mode.

In this manner, in the third mode, one slave station is always designated from which data cannot be transmitted, but the same slave station is not prohibited from transmitting data consecutively. Because,
This is because monitoring data may change at a slave station whose transmission is prohibited. Therefore, after issuing the third mode spontaneous data transmission command M3, the master station continues to issue the third mode command M3 until the data return from the slave station becomes hot, and midway through, the master station issues the third mode spontaneous data transmission command M3. Since there is no need to return to the mode or the second mode, changed monitoring data can be preferentially collected for at least one command. [Embodiment] FIG. 3 shows an embodiment of a master station and a slave station used in the monitoring data collection method according to the present invention.
Transmission times I with 0! (which may be wired or wireless), the CPU 12, the ROM 13, the RAM 14, and the CPU bus 15 that interconnects them.
and a timer 16 connected to the CPU bus l5, and each slave station 20 has an interface 2l and a timer 16 connected to the CPU bus l5.
It consists of a CPU 22, a ROM 23, a RAM 24, a CPU bus 25 that interconnects these, a timer 26 connected to the CPU bus 25, and an input section 27 that inputs monitoring data to the CPU bus. Furthermore, timers 16 and 2
6 may be performed by clock counting of CPLJ22. FIG. 4 shows the frame format of data according to the HDLC method used in the present invention, and shows the control section CONT (
1 byte), a data section DATA (0 to 228 bytes) containing station number, monitoring data, control data, etc., and CR
It is composed of a check section CHECK such as C check. This frame format is used for the master station IO and each slave station 2.
0 and is stored in the ROM 23 of the CPU 12 and 22 as appropriate. Each mode in the method of the present invention when the embodiments shown in FIGS. 3 and 4 are used is as follows. Q1' and L2L: In this mode, the polling interval for each slave station and the predetermined cycle between polls are generated by timer l6, and polling is performed. The polling operation is performed based on a well-known algorithm stored in the ROM 13 using the frame format shown in FIG.
When polling the local station, the monitoring data stored in AM24 is stored in the data section DATA of the frame format and sent back. Note that the downtime between polling ends and the next polling needs to be considered individually depending on the nature of the monitoring system, the nature of the monitored object, the nature and quality of the data transmission path, etc., but it is usually 1 to 10 minutes. The value is a guide,
Depending on the situation, it may be 30 minutes or even an hour. In this mode, the CPU 12 of the master station IO knows that the polling in the first mode has been completed, so at this time, it spontaneously sends data to the control unit CONT in the frame format shown in Figure 4. A command M2 is inserted and repeatedly transmitted from the master station 10 to each slave station 20 (see Fig. 1). Each slave station that receives this spontaneous data command M2 at the same time starts the timer count of each timer 26 from that point.
As shown in FIG. 2, the timer end time of the timer 26 differs for each slave station 20, and priority is given to the slave station whose timer expires first. As an example, this timer time is about 3Oss as shown in the figure, and the shorter this timer time is set, the shorter the timer time of the highest slave station N becomes. This approach is equivalent to being able to send . If there is a change in the monitoring data before the timer 26 expires, each slave station 20 will preferentially and spontaneously transmit the monitoring data of that slave station to the master station IO when the timer expires. Let it start. At this time, other slave stations 20
will intercept the monitoring data, and in this case the CP
U22 controls to prohibit transmission even if the timer time has expired. @I44 and HiniL: In the third mode, the master station IO, which has finished receiving the monitoring data from the slave stations 20, sends a spontaneous data transmission command M3 to each slave station 20 at this point. This command M3 is basically the same as command M2, but the difference is that a command to prohibit transmission is inserted into the control unit CONT of the frame formant and sent only to the slave station that has just finished receiving it. It is. Therefore, in a slave station for which transmission prohibition is specified by the control unit CONT, the CPU 22 prohibits transmission even if the monitored data changes again, but for other slave stations, since their own station is not prohibited from transmitting, the command M2 As in the case of , if there is a change in the monitoring data, data can be sent preferentially when the local station's timer time has elapsed. After issuing the spontaneous data transmission command M3 in the third mode, the master station 1O continues to issue the command M3 in the third mode until there is no change in the monitored data and data is no longer returned due to the timer response in the command M3. will continue to be produced. Thereafter, as described above, the mode returns to the second mode or the first mode. [Effects of the Invention] As described above, in the monitoring data collection method according to the present invention, the monitoring data collection method according to the present invention utilizes the idle time in the polling cycle to sequentially collect data based on the timer settings starting from the slave station where there has been a change in monitoring data. By making the timer time settings more detailed, slave stations whose monitoring data has changed can transmit data voluntarily at virtually any time, reducing the waiting time. can be shortened.

[Brief explanation of drawings]

1 and 2 are diagrams for conceptually explaining the monitoring data collection method according to the present invention, and FIG. 3 is a block diagram showing an embodiment of a master station and a slave station used in the method of the present invention. , FIG. 4 is a diagram showing a frame format used in the present invention, and FIGS. 5 and 6 are diagrams for explaining a conventional example. In the figure, M2... second mode spontaneous data transmission command, M3...
... Third mode spontaneous data transmission command, DI, D3.
...Monitoring data, 10...Master station, 20...Slave station. In addition, the same symbols in the figures indicate the same or equivalent parts. agent

Claims (1)

[Claims] In a method in which one master station collects monitoring data of a plurality of slave stations, a first mode in which all slave stations are polled sequentially within a predetermined cycle to collect monitoring data of the slave stations. When the polling within the cycle completes, the master station issues a spontaneous data transmission command to each slave station, and each slave station, upon receiving the spontaneous data transmission command, performs monitoring during free time until the next polling. Only one slave station whose data has changed before the end of the timer time allocated to start data transmission in a staggered manner will preferentially and spontaneously start transmitting monitoring data, and other slave stations will be prohibited from transmitting. In the second mode, when the transmission of monitoring data in the second mode is completed, the master station gives the same spontaneous data sending command as in the second mode to each slave station, and during the spontaneous data sending command, A monitoring data collection method comprising: a third mode that includes a transmission prohibition command for a slave station that has completed transmission only once;