JPS6028458B2 - Data collection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data transmission method from a slave station to a master station in a telemeter system.

A boring method is used when a plurality of slave stations are subordinate to one master station and data observed by the slave stations is transmitted to the master station.

The boring referred to here is JIS 1C General 62-3.3.
・Means bowling as defined by 3.
Transmits a data transmission command from the master station to the specified slave station,
Only the slave station to which this command has been transmitted sends back data. This method has the advantage that when one communication line is shared by multiple slave stations, the master station takes control of the line and simplifies the device configuration, but as the number of slave stations increases, , or as the amount of data at the slave station increases,
There was a drawback that the data update cycle became long.

Figure 1 is an operation time chart showing the transmission time of each station in the boring method, and the horizontal axis shows the passage of time.
la indicates transmission from the master station, 101 indicates transmission from slave station #1, 102 indicates transmission from slave station #2, and similarly, 10N indicates transmission from slave station #N.

The data update period is the time difference between 101 on the left and 101 on the right shown as transmission from slave station #1 in FIG. As the number N of slave stations increases or the transmission time of one slave station becomes longer, the data update cycle becomes longer, and changes in data that occur during that time may cause transmission omissions, as shown in Figure 1. It's obvious when you see it. The purpose of this invention is to eliminate the above-mentioned drawbacks of conventional boring methods.
The transmission mode of the slave station is divided into two types, and the slave station monitors predetermined specific data (single or plural) (the above specific data is hereinafter referred to as "monitoring data"), and changes in this monitoring data. If it has not occurred, only 1/M data of the total data of the slave station is transmitted for one bowling, so a so-called shortened transmission mode is used in which all transmission ends after M bowlings. When an outside change occurs, a so-called all-item transmission mode is used in which all data of the slave station is transmitted when the slave station is bowled, thereby preventing data changes from being omitted in transmission. Monitoring data as described above (i.e. specific data)
can be composed of data arbitrarily selected from all the data to be transmitted by the slave station. of course,
All data may be used as monitoring data. Generally, among all the data to be transmitted from a slave station, there is data representing analog quantities, that is, data consisting of multi-bit digital codes, and information such as whether a fuse is in a conductive state or blown. There is data such as data that can be represented by a 1-bit digital code, and for example, out of all data, only data that can be represented by a 1-bit digital code may be used as monitoring data. For monitoring data, a storage circuit is provided in the slave station to store the previously transmitted data, and the contents of this memory are compared with the current input of monitoring data in a comparison circuit, and if this comparison results in a mismatch. It is detected that a change outside of the monitoring data has occurred. The invention will now be further explained with reference to the drawings. FIG. 2 is an operation time chart showing the transmission of a specific slave station in an embodiment of the present invention. In the example shown in the figure, the total number of data to be transmitted by this slave station is fixed at 2M, and In the shortened transmission mode, 4 pieces of data are transmitted for one bowling,
For example, the 1st (11th), 12th (12th), 13th (13th), 5n+4, 5th (5th category) (where n is 3, 1)
, 2, 3...) respectively, the data (M.1, NO.2, N
O. 3, No. 4), (No.5, No.6, No.7
, No. 8), (Ship.9, No.10, Shame.11, M.
12), (No. 13, No. 14, No. 15, No.
．． 16), (No. 17, No. 18, No. 19, N
o. 20).

In other words, assume that M=5 in the explanation in the previous section. If all the data in the above 2 boxes is to be used as monitoring data, this slave station should be equipped with means for detecting changes in the above 20 pieces of data, and if a change outside of any of the data is detected (as shown in Figure 2). The example shows a case where a change occurred in the monitoring data between the third and fourth boring)
For the next bowling (the fourth bowling in the example of FIG. 2), all data of 2 is transmitted using the all-item transmission mode. That is, in the above explanation regarding FIG. 2, all the data to be sent by the slave station is No. 1~No.
Figure 2 shows the case where all the data in Figure 2 is used as monitoring data, and the stored contents of the previously sent data and the current data are constantly compared. There was no change in the monitoring data during the first, second, and third bowlings, so a total of three bowlings resulted in No. 2 of the solid data. 1~No. When the 12 data of No. 12 was transmitted, it was detected that a change occurred in the monitoring data between the third bowling and the fourth bowling, and in the fourth bowling, no. 1~N
o. An example is shown in which all 20 pieces of data are transmitted. In normal cases, it is not necessary to use all of the 2 fixed data as monitoring data; for example, data that changes slowly can be easily interpolated from the data before and after it even if there is a change during the data update cycle. Therefore, only data that can be expressed as a 1-bit digital code, such as data such as whether a fuse is in a conductive state or blown, is used as monitoring data, and if there is a change in the monitoring data. It is only necessary to use the all-item transmission mode. Therefore, as can be easily understood from FIG. 2, according to the method of the present invention, the data collection time for going around all the slave stations is close to 1/M of the data collection time for going around all the slave stations using the conventional method. It can be shortened, and changes in important data will not be missed.

In the above explanation, the shortened transmission mode and all-item transmission mode were explained separately, but it is possible to achieve the same purpose by transmitting changes in monitoring data without transmitting data for all items in the above-mentioned all-item transmission mode. is clear, and in this specification, the transmission mode when no change occurs in the monitored data is tentatively referred to as the first transmission mode, and the transmission mode when a change occurs in the monitored data is tentatively referred to as the second transmission mode. I'll decide.

How to determine the first transmission mode and the second transmission mode is a matter of design, and it is important to transmit as much data as possible through one communication line and to minimize the changes that should occur outside of the data to be transmitted. The data should be appropriately designed so that the data can be transmitted without time delay, and the shortened transmission mode and all-item transmission mode shown in FIG. 2 are examples of this. Furthermore, although the above description has been made regarding the case of a boring type telemeter, it is clear that the present invention is generally applicable to cyclic data transmission methods. For example, data that does not change suddenly like analog data is transmitted in 1/n increments, and monitoring data is transmitted in 1/n increments when no change occurs, and all data is transmitted when a change is detected. The above-mentioned first transmission mode and second transmission mode can be designed to do so.

As is clear from the above description, the present invention has the advantage that the data update cycle can be shortened.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an operation time chart showing the transmission time of each station in the boring system, and FIG. 2 is an operation time chart showing the transmission of a specific slave station in an embodiment of the present invention.

In these figures, la is the transmission time of the master station, 101 is the transmission time of slave station #1, 102 is the transmission time of slave station #2, and 1-
This is the data number of the data to be transmitted by two rivers.

Figure 1 Figure 2

Claims (1)

[Claims] 1. A step of detecting whether or not a change has occurred in predetermined specific data (single or plural) since the previous transmission on the data transmission side of the telemeter system; If not, the first predetermined
The data is sequentially transmitted according to the transmission mode of A data collection method characterized by comprising a step of sending on occasion. 2. In the data collection method set forth in claim 1, the predetermined specific data is data that can be represented by a 1-bit digital code, among all the data to be transmitted from the data transmitting side. A data collection method characterized by including the total number of. 3. The data collection method according to claim 1, wherein the data transmitted according to the second transmission mode is comprised of all data to be transmitted on the data transmission side. Method.