JP2000032012A - Polling communication method and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system where the number of limited polling times of a master station can be effectively utilized by performing the polling communication after shortening the polling cycles set to the slave station groups of higher priorities compared with the polling cycle set when all slave stations have the same priority based on the polling communication priority that is decided in a priority deciding step. SOLUTION: An office number generation circuit 1 starts its processing at each time that is set by a timer 2 with priority set at the highest level L. Then the number of slave stations having levels L is checked. If no slave station has level L, the priority level is subtracted by 1. If one or more slave stations have levels L, the value of a pointer (p) is decided. As a result, the value of the pointer (p) is set at 1 when the pointer (P) value is equal to the number of slave stations of the same priority level with the priority level subtracted by 1. Then the number NL of slave stations of the levels L is checked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a station configuration comprising one master station and N slave stations, when the polling time per slave station of the master station cannot be shorter than the current situation, a slave station that polls. The present invention relates to a polling communication method and a polling communication system in which stations are divided into levels and priorities are assigned, so that the slave station polling cycle of the highest priority group can be shorter than the polling cycle when all the slave stations have the same level.

[0002]

2. Description of the Related Art Some conventional polling communication methods and polling communication systems assign a priority to each slave station and perform communication with each slave station based on the priority. There is also a polling communication method in which the priority is set to the same level and polling is sequentially performed. According to the communication method of setting the priority to the same level, one polling cycle Pm of a certain slave station C is N * T (N: number of stations, T: polling time per slave station), and the number N of stations is equal to N * T. If the number is large, the polling period Pm becomes a very large value. For example, when a failure occurs in a slave station, it may be too late to wait N * T time. Also, if a failure occurs in a slave station, if only the failed slave station is polled,
The situation of other slave stations cannot be grasped at all.

[0003]

Since the conventional polling communication method and the conventional polling communication system are configured as described above, when the number of times of polling of the master station is limited, if the number N of slave stations is large, polling is performed. Period Pm
If a communication system that performs polling only with a specific slave station is used, communication with other slave stations cannot be performed at all, and the limited number of times of polling of the master station cannot be used effectively. There were challenges.

Accordingly, an object of the present invention is to provide a slave station having a low priority level in a situation where the number of times of polling of the master station is limited, but the polling cycle is longer than the conventional polling cycle, but no polling is performed at all. It is an object of the present invention to provide a polling communication method and a polling communication system which can effectively utilize a limited number of polling times of a master station so as not to be in a state of being left out.

[0005]

According to the polling communication method of the present invention, the priority assigning step of assigning priorities to the slave stations to be polled, and the priority assigned to each slave station in the priority assigning step are the same. The number of said slave stations in priority order;
Based on the same priority slave station number, for each of the same priority slave station groups, and for each of the slave station numbers within the same priority order, polling communication with respect to a higher priority slave station group. A priority determining step of prioritizing the priorities and determining a polling communication order for the higher priority slave station group and a lower priority slave station group; and the polling communication order determined in the priority determining step. And a polling communication step of performing polling communication by shortening a polling cycle for the higher priority slave station group than a polling cycle when all the slave stations have the same priority.

A polling communication system according to the present invention comprises:
Perform polling communication between one master station and multiple slave stations,
In the polling communication system in which the master station collects information from the plurality of slave stations, the master station has a priority assigned to the slave station, the number of the slave stations having the same priority, and the same priority. For each slave station group of the same priority, and for each slave station number within the same priority, a slave station group of a higher priority and a child of a lower priority When the polling communication order for the station group is determined, the polling communication order for the higher priority slave station group is prioritized, and the polling cycle for the higher priority slave station group is set to the same priority for all the slave stations. Station number generating means for shortening the polling cycle.

A polling communication method and a polling communication system according to the present invention are arranged so that, in a polling communication method performed between one master station and a plurality of slave stations, for example, the polling time per slave station of the master station is lower than the current state. If it cannot be shortened, the polling slave stations are divided into levels and priorities are assigned, and the assigned priorities of the slave stations, the number of the slave stations having the same priority, and the slave station numbers having the same priority are assigned. The polling communication order for the higher priority slave station group is prioritized for each slave station group having the same priority and for each slave station number within the same priority, and the higher priority Determining the polling communication order for the slave station group and the lower priority slave station group,
Based on the determined polling communication order, the polling cycle of the higher priority slave station group is shorter than the polling cycle when all the slave stations are at the same level, and the lower priority slave station is used. However, the polling cycle is longer than the conventional polling cycle, but no polling is performed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below. FIG. 1 is a block diagram showing a configuration of a polling communication system to which a polling communication method according to the present embodiment is applied. This polling communication system includes a master station B and N slave stations C. The master station B and the slave stations C are connected by transmission lines N1 and N2, and one master station B is composed of N slave stations. In this configuration, station information a of C (station number s = 1 to N) is collected by polling.

The master station B includes a station number generating circuit (station number generating means) 1, a timer 2 for generating time information, a station number transmitting circuit 3, and an information receiving circuit 4. The station number generating circuit 1 has information such as a level 11, a number 12, a pointer 13, and a station number list 14. The station number generation circuit 1 is a circuit that generates a station number n to be polled every time T generated by the timer 2. The station number transmission circuit 3
This is a circuit for transmitting the station number n generated by the station number generation circuit 1 to N slave stations C. The information receiving circuit 4 is a circuit that receives the station information a of the slave station n.

Each slave station C has a station number receiving circuit 5, a comparing circuit 6, a local station number storing means 7 for storing the local station number,
An information transmitting circuit 8 and a local station information storing means 9 for storing generated local station information are provided. The station number receiving circuit 5 is a circuit that receives the station number n transmitted from the master station B. The comparison circuit 6 is a circuit that compares the station number n received by the station number reception circuit 5 with the station number of the own station stored in the own station number storage means 7 to determine a match. The information transmitting circuit 8 transmits the station information a stored in the own station information storing means 9 to the master station B when the station number n received by the station number receiving circuit 5 matches the station number of the own station. It is.

Next, the operation will be described. In the polling communication method and the polling communication system of the present embodiment, in a station configuration including one master station B and N slave stations C, the polling time T per slave station of the master station B is smaller than the current state. When the length cannot be shortened, the polling slave stations are divided into levels and priorities are assigned, so that the polling cycle PL of the slave station of the highest priority group L can be shorter than the polling cycle Pm when all the slave stations have the same level. Is what you do. In this case, assuming that the number of stations belonging to the priority level A is NA, the polling period PA of the slave station of the priority level A is PA = (NA + 1) * PA + 1, PL =
(NL + 1) * T.

The station number generating circuit 1 of the master station B generates a station number n to be polled every time T generated by the timer 2, and the station number transmitting circuit 3 converts the generated station number n into N children. Send to station C. Each of the slave stations C receives the station number n transmitted from the master station B by the station number receiving circuit 5, and compares the station number n of the own station by the comparing circuit 6 with the station number s of the own station stored in the own station number storage means 7. When the station number n and the station number s match, the information transmitting circuit 8 transmits the station information a stored in the own station information storage means 9 to the master station B. In the master station B, the information receiving circuit 4 receives the station information a of the slave station n.

The station number generating circuit 1 of the master station B assigns the station numbers n (n = 1 to N) of the slave stations to L priority levels (priority levels 1 to L) 11, and Station number list S (priority level, value of pointer p or initial value) indicated by reference numeral 14 of each slave station belonging to any of the assigned priority levels, and number N indicated by reference numeral 12 of slave stations of each priority level , And the pointer p indicated by reference numeral 13. Here, it is assumed that the priority of the level 11 rises from the priority level 1 to the priority level L.

FIG. 2 shows that the priority level is set in a range from the priority level 1 to the priority level 3, the station numbers of the slave stations belonging to the priority level 3 are set to the station numbers 1 and 2, and The station numbers of the slave stations belonging to the priority level 2 are set to the station numbers 3, 4, and 5, and the station numbers of the slave stations belonging to the priority level 1 are the station numbers 6, 7 and 7. 8, the number N of slave stations when set to the station number 9, the pointer p (indicating the number of the slave station of the same priority level), and the specific values of the station number list S. .

FIG. 3 shows the relationship between the operation of the pointer p and the generated station number n when the station number generating circuit 1 operates based on the configuration of FIG.

FIG. 4 is a flowchart showing the characteristic operation of the polling communication method and the polling communication system in which the polling cycle of the slave station of the highest priority group is shorter than the polling cycle when all the slave stations are at the same level. It is. It is assumed that the initial values of the pointers p of the respective priority levels are all initially set to "1".

According to this flowchart, first, the station number generating circuit 1 starts the process for each time T generated by the timer 2. In step S101, the priority level is set to the highest priority level L. Next, in step S102, the value of the number NL of the set slave stations having the highest priority level L is checked. As a result, when the number is zero, step S
Go to 107 and change the value of the priority level to the priority level L
Is set to a value obtained by subtracting “1” from the above, and the process returns to step S102.

On the other hand, if the number is not zero, step S103
Proceed to. In step S103, the value of the pointer p (the number of the child station having the same priority level) is determined. As a result of the determination of the value of the pointer p in step S103, when the value of the pointer p is the number of slave stations having the same priority level, the process proceeds to step S106, the pointer value is set to "1", and the priority is set in the subsequent step S107. Degree level value is "1"
Return to step S102 with the subtracted value. On the other hand, if the value of the pointer p is not the number of slave stations having the same priority level, the process proceeds to step S104. Step S1
In step 04, the station number of the station number list S (priority level, pointer p) pointed to by the pointer p is set as the station number n to be polled, and the process proceeds to step S105.
The value of the pointer p is incremented by "1", and the process ends.

By the above processing, if the number of stations belonging to the priority level A is NA, the polling period PA of the slave station of the priority level A is PA = (NA + 1) * PA + 1.

Here, the operation of the station number generation circuit 1 will be further described with reference to the flow chart of FIG. 4 based on FIG. 3 based on the configuration of FIG.
In step 101 → step S102 → step S103 → step S104, the station number list S (priority level = 3, pointer value p3 = 1) is selected and the polling station number n becomes, and subsequently, in step S105, the pointer value p3 =
It becomes 2. Similarly, at time 2T, in step S104, the station number list S (priority level = 3, pointer value p3 =
2) is selected and the polling station number n becomes, and then the pointer value p3 = 3 in step S105.

At time 3T, step S101 →
Step S102 → Step S103: pointer value p3
= 3, the process proceeds to step S106, and the process proceeds to step S106.
In step S107, the priority level is set to 2 and the processing returns to step S102. In step S103 → step S104, the station number list S (priority level = 2, pointer value = 1) is selected and polled. The number n becomes, and then the pointer value becomes p2 = 2 in step S105. Hereinafter, the station number n to be polled in the same manner as shown in FIG.
→→→→ ...

The polling periods P3, P2, and P1 of the slave stations belonging to the respective priority levels 3, 2, and 1 are P3 = (N3
+1) * T = (2 + 1) * T = 3T, P2 = (N2 +
1) * P3 = (3 + 1) * 3T = 12T, P3 = (N1
+1) * P2 = (4 + 1) * 12T = 60T. Therefore, the polling period P when all the slave stations have the same level
m is (N3 + N2 + N1) * T = (2 + 3 + 4) * T =
Because of 9T, the period P3 of priority level 3 is 3/9 of Pm.
= 1/3 times. Here, T is the polling time per slave station of the master station B.

As described above, according to the present embodiment, the polling period PL of the slave stations belonging to the highest priority level L is (NL + 1) * T, and all the slave stations have the same level. The polling time is reduced by (NL + 1) / N times as compared with a certain polling period Pm = N * T.

The present invention is not limited to the above-described embodiment. For example, the number of slave stations belonging to each priority level in the above-described embodiment is dynamically changed according to the situation of the slave station. When configured in this way, the polling communication order for the higher priority slave station group and the lower priority slave station group may be dynamically changed and determined according to the situation of the slave station. Based on the determined polling communication order, priority is given to the polling communication order for the higher priority slave station group, and the polling cycle of the higher priority slave station group is the same for all slave stations. The polling cycle when the level is set can be shortened.

[0025]

As described above, according to the present invention, based on the priority assigned to the slave stations, the number of the slave stations having the same priority, and the slave station number having the same priority. For each slave station group having the same priority, and for each slave station number within the same priority, determine a polling communication order for a slave station group having a higher priority and a slave station group having a lower priority. , Based on the polling communication order,
Since the polling communication order for the higher priority slave station group is prioritized and polling communication is performed from the master station to each slave station, the higher priority is used in polling communication between the master station and each slave station. While the slave station group with the highest priority has the highest priority, the slave station with the lower priority has a longer polling cycle than the conventional polling cycle, but no polling is performed at all. The polling cycle for the slave station group is shorter than the polling cycle when all the slave stations have the same priority, so that the limited number of polls of the master station can be effectively used.

Further, the number of slave stations belonging to the same priority can be dynamically changed according to the situation of the slave stations, so that the number of slave stations of higher priority and slave stations of lower priority can be changed. The polling communication order can be dynamically changed and determined according to the situation of the slave station, and based on the determined polling communication order, the polling communication order for the higher priority slave station group is prioritized. In addition, the polling cycle of the slave station group having the higher priority can be shortened than the polling cycle when all the slave stations have the same level.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a polling communication system to which a polling communication method according to an embodiment of the present invention is applied.

FIG. 2 is an explanatory diagram showing a specific example of a priority level, a station number, a number, a pointer, and a station number list of a slave station of a polling communication system to which a polling communication method according to an embodiment of the present invention is applied; is there.

FIG. 3 is an explanatory diagram showing a relationship between a pointer operation and a generated station number when a station number generation circuit of a master station of a polling communication system to which a polling communication method according to an embodiment of the present invention is applied; is there.

FIG. 4 is a flowchart showing a characteristic operation of the polling communication method and the polling communication system according to the embodiment of the present invention.

[Explanation of symbols]

1 ... station number generating circuit (station number generating means), 11 ... priority level, 12 ... number of slave stations of the same priority level,
13: Pointer, 14: Station number list, B: Master station, C slave station.

Claims (4)

[Claims] 1. A priority assigning step for assigning priorities to slave stations to be polled, the priority of slave stations assigned in the priority assigning step, the number of the slave stations having the same priority, and the same priority. Based on the slave station number of each of the slave station groups of the same priority, and for each of the slave station numbers within the same priority, the priority of the polling communication for the slave station group of the higher priority. A priority determining step of determining a polling communication order for the higher priority slave station group and a lower priority slave station group; based on the polling communication order determined in the priority determining step, Polling that performs polling communication with a shorter polling cycle for a higher priority slave station group than when all slave stations have the same priority Polling communication method and a signal step. 2. The priority order determining step, wherein the same priority order slave station number setting step for setting the number of slave stations having the same priority order, and a slave station for setting the slave station number of each slave station having the same priority order A number setting step; a pointer setting step of setting a pointer indicating to which of the slave stations of the same priority order the polling communication order has been determined; and a pointer setting step of setting the same priority slave station number setting step. The number of slave stations determining the number of higher priority slave stations based on the number of slave stations determined, the number of slave stations determined in the slave station number determination step, and the number of slave stations determined in the pointer setting step Based on the value of the pointer and the slave station number of each slave station set in the slave station number setting step, for each slave station group having the same priority, and for each slave station number within the same priority. The higher priority order Claim, characterized in that it comprises a child station group and a lower slave station polling communication priority determination step of determining a polling communication priority for the group of priority 1
The polling communication method described. 3. The mobile station according to claim 1, further comprising a mobile station number changing step of dynamically changing the number of mobile stations belonging to the same priority according to the status of the mobile station. Polling communication method. 4. A polling communication system in which polling communication is performed between one master station and a plurality of slave stations, and the master station collects information from the plurality of slave stations, wherein the master station is a slave station. , The number of the slave stations having the same priority, and the slave station number having the same priority, for each of the slave station groups having the same priority, and within the same priority. For each of the slave station numbers, determine the polling communication order for the higher priority slave station group and the lower priority slave station group, and prioritize the polling communication order for the higher priority slave station group. And a station number generating means for making the polling cycle for the higher priority slave station group shorter than the polling cycle when all the slave stations have the same priority. Communication system.