JPH02209041A - Method for detecting faulty slave station - Google Patents

Abstract

PURPOSE:To detect a slave station to be faulty early without any wait time by recognizing it at which slave station fault takes place depending on a decremented count in a count area of a circulated communication frame, returning an address of a normal slave station at present immediately and detecting the faulty slave station. CONSTITUTION:A master station 10 uses a readout section 31 to read a count from a count area 22 of a circulated communication frame, sets a rearranged number to a transmission destination address area 20 of the circulated communication frames of the number to be decremented with an instruction setting section 32 when the count is decremented sequentially, writes an instruction representing the return of its own station to a return instruction write area 23 and sends the result and writes the address of its own station to an address write area 24 of the communication frame and returns it from the slave station of the said rearrangement. Then the address of the normal slave station is recognized from the address written in the address write area 24 of the communication frame received sequentially.

Description

[Detailed description of the invention] [Summary] Regarding a method for detecting a faulty slave station in a loop network in which a master station and a plurality of slave stations are connected in a loop, a faulty slave station detection method that can quickly detect a faulty slave station In order to provide a method, in the master station, the initialization unit sets an initial value in the count value area of the communication frame and transmits it, and in each slave station, the read addition setting unit sets the initial value from the count value area. The value is read out, 1 is added to it, and the value obtained by adding 1 is set in the count value area and transmitted, and it is also stored as a sort order. In the master station, the reading unit reads out the value of the circulating communication frame. Read the setting value from the count value area, grasp the number of slave stations,
If there is a change, use the command setting section to set the sequential order number in the transmission destination address area of the communication frame circulating the changed number of times, and send the address of the own station back to the return command writing area. When the slave station receives this, it detects whether the address corresponds to the order of its own station in the sorting order address detection own station address setting section, and if it is addressed to its own station, it uses the address of the communication frame. The master station writes and transmits the address of its own station in the write area, and the master station sequentially receives these communication frames, and the slave station address recognition unit reads and recognizes the normal slave station address from the address write area. Configure it as follows.

[Industrial Application Field] The present invention provides a loop network in which a master station and a plurality of slave stations are connected in a loop through a transmission path, in which a master station can detect a failed slave station quickly (a failure that can be detected). This invention relates to a slave station detection method.

[Conventional technology]

FIG. 6 is a diagram showing an example of a loop type network, FIG. 7 is a diagram showing a frame format of a communication frame in the case of polling in a conventional example, and FIG. 8 is a sequence diagram for detecting a faulty station in a conventional example.

As shown in FIG. 6, in a loop type network, a master station 10 and five stations from a slave station 11 at address A to a slave station 15 at address E are connected in a loop through a transmission path, and a slave station at address B 12. Detection of a faulty station by the master station 10 when the slave station 15 at address E becomes faulty and is bypassed will be described below as an example.

Conventionally, to detect a faulty station, as shown in FIG. 7, the destination address area 20. A return command writing area 23 in which a command to return the address of the own station is written in the control area of the circulating communication frame having the source address area 21, and an address writing area 24 in which the address of the own station is written.
The master station 10 writes its own address in the source address area 21, first writes the address A of the first slave station 11 in the destination address area 20, and writes the address A of the first slave station 11 in the return command writing area 23. A command to return the address of the own station is written and transmitted as shown in FIG.

Then, the slave station 11 writes its own address A into the address writing area 24 and sends it back.

This allows the master station 10 to know that the slave station 11 is not at fault.

Next, the second slave station 12 is added to the destination address area 20.
Write address B of , and transmit as shown in FIG. 8 in the same manner as above.

Since this funder station 12 is bypassed due to a failure, no return is made.

The master station 10 waits for a return, but times out and learns that the slave station 12 is at fault.

Next, the address C of the third slave station 13 is written in the destination address area 20, and the transmission is performed in the same manner as above, as shown in FIG.

Then, the slave station 13 writes its own address C into the address writing area 24 and sends it back.

This allows the master station 10 to know that the slave station 13 is not at fault.

Similarly, it is determined that the slave station 14 (address D) is not at fault, and that the slave station 15 (address E) is at fault.

[Problem to be solved by the invention]

However, in the conventional method of detecting a faulty slave station, the master station 10 waits until a timeout occurs in the master station 10 before detecting the address being written in the address writing area 24 and sent back, so there is a problem that the detection is delayed. be.

An object of the present invention is to provide a faulty slave station detection method that allows a master station to quickly detect a faulty slave station.

[Means to solve the problem]

FIG. 1 is a diagram showing the principle of the present invention.

As shown in FIG. 1(A), there is a count value area 22 in which a count value is written in a circulating communication frame that has a destination address area 20 and a source address area 21, and a command to return the address of the own station. A return command writing area 23 for writing and an address writing area 24 for writing the address of the own station are provided.

Further, as shown in FIG. 1(B), the master station 10 includes an initialization section 30. Reading unit 31. Command setting section 32. The slave station address recognition unit 33 is connected to the plurality of slave stations 11, 12, 13 .・・・
- is provided with a read addition setting section 40 and a sort order address detection own address setting section 41.

Then, in the master station 10, the initialization unit 3o sets an initial value in the count value area 22 of the communication frame and transmits it, and in each slave station, the read addition setting unit 40 sets the count value. Read the count value from area 22, add 1,
The value obtained by adding 1 is set in the count value area 22 and transmitted, and is also stored as the arrangement order.

In the master station 10, the readout section 31 reads out the set value from the count value area 22 of the circulating communication frame to determine the number of slave stations.

In this way, the number of slave stations is always kept track of, and if there is a change, the command setting unit 32 sequentially sets the number in the order of arrangement in the transmission destination address area 20 of the communication frame that circulates according to the changed number. is set, and a command to return the address of the own station is written in the return command writing area 23 and transmitted.

The slave station that receives this detects whether the address corresponds to the order of arrangement of the own station in the order address detection own address setting section 41, and if it is addressed to the own station, writes the address in the address writing area of the communication frame. 24 and send it.

Then, the master station 10 sequentially receives these communication frames, and the core slave station address recognition section 33 reads and recognizes the normal slave station address from the address writing area 24.

[For production]

According to the present invention, the master station 10 uses the reading unit 31 to read the count value from the count value area 22 of the circulating communication frame, and by checking whether the count value decreases or not, the master station 10 always prevents the blockage from becoming an obstacle and bypassing the communication frame. Detecting whether there are any slave stations present.

Then, when the count value decreases, the command setting unit 32 sequentially sets the serial number in the transmission destination address area 20 of the communication frames circulating in the decreased number, and the own station in the return command writing area 23. A command to return the address of the communication frame is written and transmitted, and the slave stations in the corresponding arrangement order write their own addresses in the address writing area 24 of the communication frame and send them back.

Then, the address of the normal slave station is recognized from the address written in the address writing area 24 of the communication frames sequentially received.

Therefore, a faulty slave station can be detected.

In this case, the faulty slave station can be detected without waiting time, so the detection time can be shortened.

〔Example〕

FIG. 2 is a diagram showing the frame format of a communication frame in an embodiment of the present invention, FIG. 3 is a block diagram showing the configuration of the main part of a master station in an embodiment of the present invention, and FIG. 4 is an embodiment of the present invention. FIG. 5 is a block diagram showing the configuration of a slave station, and FIG. 5 is a sequence diagram for detecting a faulty station according to an embodiment of the present invention.

In the case of the present invention, the second
As shown in the figure, a count value area 22 is further provided than in the conventional example shown in FIG.

In addition, the master station 10 shown in FIG. 6 includes an initialization section 30, in addition to a data processing section 34 that performs normal processing, as shown in FIG.
Reading unit 31. Command setting section 32゜Slave station address recognition section 3
3 will be provided.

Further, as shown in FIG. 4, the slave stations 11 to 15 shown in FIG. 6 include a reading section 42, in addition to a data processing section 49 that performs normal processing. Addition section 43. Setting section 44゜ Own station address setting section 4
5. Storage unit 46. Sort order address detection/command analysis section 47
．． A comparison section 48 is provided.

Then, in the master station 10, the initialization unit 30 sets the initial value 0 in the count value area 22 of the communication frame and transmits it, and in each slave station, the readout unit 42 reads the count value from the count value area 22. Read, add 1 in addition section 43, and add l
The setting unit 44 sets the added value in the count value area 22 and transmits it, and also stores it in the storage unit 46 as the arrangement order.

Therefore, the arrangement order of the slave stations 11 in FIG. 6 is l, and the slave stations 1
The arrangement order of 2 is 2, and the arrangement order of slave stations 13, 14, 15 is 3, 4.5, and a communication frame whose count value area 22 is 5 is input to the master station 10.

In the master station 10, the reading unit 31 reads the count value area 22.
5 is read out, and it is found that the number of slave stations is 5.

If a slave station fails and is bypassed, communication frames will not be input to the bypassed slave station and the count value will be 1.
is not added, the count value in the count value area 22 decreases by the number of slave stations that have caused a problem.

By decreasing the number, the master station 10 knows that one of the slave stations has become a failure.

In this case, if slave station 12.15 becomes a failure, the order of slave stations 11 will be 1. The arrangement order of the slave stations 13 is 2, the arrangement order of the slave stations 14 is 3, and the count value in the count value area 22 is 3.

Therefore, the master station 10 writes 1 and 2.3 in the destination address area 20 of the three communication frames, writes the address of the master station in the source address area 21, and writes the return command write area of each communication frame. 23, a return command to return the address of the own station is written and transmitted.

Then, in the slave station 11, 13, 14, the order address detection/command analysis section 47 takes in the order address from the destination address area 20 of the communication frame, and the comparison section 4
At step 8, the communication frame is compared with the arrangement order stored in the storage unit 46, and if it matches, the communication frame is fetched, the return command to return the address of the own station is decoded from the return command writing area 23, and the communication frame is fetched. The local station address setting section 45 sets the local station address (
In this case, slave stations 11.13. 14, write the addresses A, C, and D of the own station, respectively), and transmit as shown in FIG.

The master station 10 sequentially receives these communication frames, and the slave station address recognition unit 33 reads out the addresses from the address writing area 24, thereby recognizing that the slave stations with addresses A, C, and D are normal. However, it learns that slave stations 12.15 with addresses B and E are at fault.

In other words, when the count value decreases, it is recognized that a failure has occurred in one of the slave stations, and the address of the currently normal slave station is immediately returned to detect the failed slave station.
There is no waiting time and a failed slave station can be detected quickly.

〔Effect of the invention〕

As explained in detail above, according to the present invention, it is recognized that a failure has occurred in one of the slave stations due to a decrease in the count value in the count value area of the circulating communication frame, and the address of the currently normal slave station is immediately set. Since the faulty slave station is detected by sending back the faulty slave station, there is no waiting time and the faulty slave station can be detected quickly.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of the present invention. FIG. 2 is a diagram showing the frame format of a communication frame in an embodiment of the present invention. FIG. 3 is a block diagram showing the configuration of the main part of a master station in an embodiment of the present invention. , Fig. 4 is a block diagram showing the configuration of a slave station according to an embodiment of the present invention, Fig. 5 is a sequence diagram of faulty station detection according to an embodiment of the present invention, and Fig. 6 is a diagram showing an example of a loop type network. , FIG. 7 is a diagram showing the frame format of a communication frame in the case of polling in the conventional example, and FIG. 8 is a sequence diagram for detecting a faulty station in the conventional example. In the figure, 10 is a master station, 11 to 15 are slave stations, 20 is a destination address area, 21 is a source address area, 22 is a count value area, 23 is a return command writing area, 24 is an address writing area, and 30 is an address writing area. Initialization unit, 31.42 is a readout unit, 32 is an instruction setting unit, 33 is a slave station address recognition unit, 34.49 is a data processing unit, 40 is a readout addition setting unit, 41 is a sort order address detection local station address 43 44 is a setting section; 45 is a local address setting section; 46 is a storage section; address setting section; 47 is a sequence address detection/command analysis section; and 48 is a comparison section. Frame A7 zoomer ll'-8 surface meg diagram

Claims (1)

[Claims] A master station (10) and a plurality of slave stations (11, 12, 13, . . .
) are connected in a loop through a transmission path, the destination address area (20) and the source address area (20)
1), a count value area (22) in which a count value is written in the circulating communication frame [(A)], a return command writing area (23) in which a command to return the address of the own station is written, and An address writing area (24) is provided in which the address of
31), command setting section (32), slave station address recognition section (3
3), the plurality of slave stations (11, 12, 13, . . . ) are provided with a read addition setting section (40), a sort order address detection own station address setting section (41), and the master station ( 10), the initialization unit (30) sets an initial value in the count value area (22) of the communication frame and transmits it, and in each slave station, the read addition setting unit (40)
Read the count value from the count value area (22),
1 is added, and the value obtained by adding 1 is stored in the count value area (22
) is set and transmitted, and is stored in the sort order, and in the master station (10), the reading unit (31) reads the set value from the count value area (22) of the circulating communication frame. Read the number of slave stations, and if there is a change, use the command setting unit (32) to set the serial number in the transmission destination address area (20) of the communication frame that circulates according to the changed number. , writes and transmits a command to return its own address in the return command writing area (23), and the slave station that receives this writes the address in the sorted address detection own address setting unit (41). If it is addressed to the own station, the master station (10) writes the address of the own station in the address writing area (24) of the communication frame and sends it. Detecting a faulty slave station, the slave station address recognition section (33) reads and recognizes the address of a normal slave station from the address writing area (24). Method.