JPH0323029B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention provides a method for monitoring whether each communication device is normal or not in a system in which a plurality of communication devices are connected in a loop through a transmission path and data is transmitted between each communication device. It is related to. [Prior Art] In such communication systems, the transmission right is acquired by transmitting a transmission right request signal, and communication is carried out under the initiative of the communication device that has acquired this. Means is used to monitor whether each communication device is normal or not. Conventionally, monitoring is performed by only one specified communication device among the communication devices. [Problem to be solved by the invention] However, with conventional means, only one communication device performs monitoring, so if a failure occurs in this communication device itself, it becomes impossible to monitor the entire system. It's causing problems. [Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention is constituted by the following means. In other words, in the above communication method, the communication device that has acquired the transmission right is determined in response to a transmission right request signal during a certain monitoring period, and the communication device that has acquired the transmission right is stored in the sub-table corresponding to each communication device. A code indicating each communication device that does not acquire the right to transmit is registered as abnormal, and the contents of this sub-table are compared with the contents of the main table in which the results during the previous monitoring period are registered to determine whether each communication device is correct or not. Then, the contents of the main table are updated based on the contents of the sub-table, and the above operation is repeated in at least a plurality of communication devices. [Function] Therefore, by comparing the contents of the main table and the sub-table, it is possible to determine whether each communication device is correct or not, and by performing this on at least a plurality of communication devices, it is possible to prevent any failure in the monitoring function. Even if this occurs, the monitoring function of the entire system will not be lost. [Example] Hereinafter, details of the present invention will be explained with reference to figures showing examples. FIG. 2 is a block diagram showing the configuration of each communication device. The communication device CE consists of a terminal device TE and a transmitting/receiving section SR. At its receiving end R, a receiving side transmission line L _R made of an optical fiber is connected to a photoelectric terminal. The communication device CE is connected via the converter O/E, and a switch SW is inserted between this and the transmitting side transmission line L _S of the optical fiber via the electro-optic converter E/O. According to the control based on the judgment, when the communication device CE has the transmission right, it selects the transmission right S of the communication device CE, and when it does not have the transmission right, it selects the reception transmission path L _R side, and this is connected to the transmission side transmission path L _S It is designed to connect to. Therefore, if the switch SW selects the receiving end R side, the communication device CE is only capable of receiving.
It is removed from the transmission path, and the signal from the reception side transmission path L _R is transmitted as is to the transmission side transmission path L _S , so that no transmission delay occurs due to the intervention of the communication device CE. Also, if the switch SW selects the sending end S side,
Both transmission paths L _R and L _S are separated, and the communication device CE can freely transmit and receive data. FIG. 3 is an overall block diagram based on the configuration of FIG. 2, in which the converters O/E and E/O are omitted, and the communication devices CE _A to CE _D are connected to the respective transmission lines L ₁ to L ₄ . In addition to connecting the _{switches in} a loop with The transmission and reception status of various signals is shown. Here, first, as shown in period _A of FIG. 3A and _{FIG .}
On the other hand, if the communication device CE _C that received this from the receiving end R sends a response signal AS _C , this is given to the receiving end R of the communication device CE _A , and the communication device
Data communication is performed between CE _A and CE _C. Next, when the communication device CE _A finishes transmitting the data signal DT _A and receiving the response signal AS _C , the communication device CE A transmits a completion signal CD _C to the communication device CE _C.
CE _C sends a confirmation signal CU _C upon receiving the termination signal CD _C
Immediately after that, the switch SW _C is set to the receiving end R side, as shown in FIG. 3B, and all the communication devices CE _B to CE _D enter the receiving mode of receiving only. After receiving the confirmation signal CU _C , the communication device CE _A :
After a predetermined period of time has elapsed for the communication device CE _C to change the switching device SW _C to state B, it sends a takeover signal CP indicating that the transmission right is to be taken over as shown in period B in Fig. 4 as a global signal (hereinafter referred to as GLS). ) and send as
When the communication device CE _A receives this via all transmission paths L ₁ to _{L 4} , it should judge that this has been received by the other communication devices CE _B to CE _D and recognize the handover signal CP as valid. This is received by the other communication devices CE _B to CE _D , and the communication device CE _B transmits the data to be transmitted to itself based on the judgment in response to the valid takeover signal CP. If it has one, it controls its own switch SW _B to select the transmitting end S side, enters the transmitting mode shown in FIG. 3C, and stands by. Next, as shown in period C in FIG. 4, the communication device CE _A transmits the data to be transmitted after the required time has elapsed until the other communication device that has the transmission _data sets the switch to state C. If the transmitter has a request signal CT _A with a unique address code indicating a request for transmission rights, it also adds a priority code () indicating the priority of the transmitted data and requests these. Send as signal CT _A (). Then, this is received by the communication device CE _B , and if the priority of the transmission data it owns is (), it is determined that it should acquire the transmission right preferentially by comparison with this, and the communication device CE _B As GLS, the request signal CT _B () to which has added the priority code () and its own address code is given as GLS.
This is received at the communication device CE _A for transmission as shown in period C of FIG. The communication device CE _A receives the received request signal CT _B ()
By comparing this with its own priority (), it is determined that the transmission right should be handed over to the communication device CE _B , and the request signal CT _B () is transmitted as is as shown in period C in Figure 4, and then the switching Set the receiver SW _A to the receiving end R side, and set it to the state shown in Fig. 3D. Request signal CT _B () transferred from communication device CE _A
When the communication device CE _B receives this, it is determined that the transmission right has been granted to itself, and after transmitting the activation signal OK that validates the request signal CT _B (), the period shown in Fig. 4 Communication equipment as shown in D.
Since CE _B sends a response request signal CS _D with the destination address and self-address codes added, if the communication device CE _D is specified by the destination code, the same device CE _D responds to the switch SW _D. is on the sending end S side, the state shown in Figure 3E is reached, and the communication device CE _D sends a confirmation signal CU _D as shown in period E in Figure 4, so the communication device CE _B receives this confirmation signal. After that, the data signal DT _B is sent to the communication device.
CE _D sends a response signal upon reception of data communication DT _B
Start sending _ASD . Therefore, data communication is performed between communication devices CE _B and CE _D , and each of the above operations is repeated in response to the end of data communication, and each communication device CE _A to CE _D Since data is transmitted sequentially starting from priority data, there is no delay in transmitting important data. In addition, takeover signal CP, request signal CT _A (), CT _B
In GLS such as (), each communication device that transmits receives and confirms what it has transmitted, and accordingly transmits an activation signal OK, so if the transmission path L ₁ ~L If there is a failure in any of _{the four} , it will not be possible to confirm its own reception, and the activation signal will not be received.
OK will not be sent, and communication devices after the failure point will not receive GLS, and only the communication devices before this will be prevented from going into a response state by receiving GLS. In addition, as GLS, each of these signals CP and CT
In addition, data such as time, alarm, and shared data are handled in the same way, and the activation signal OK is sent after receiving the self-transmitted GLS, and each communication device that receives it In response to receiving the GLS, it temporarily stores it in the buffer memory and waits for it, and in response to receiving the validation signal OK, reads and decodes the contents of the buffer memory, and performs the corresponding operation. Therefore, the reception status of GLS is determined only by the communication device that sent it, and it is only necessary to send the activation signal OK, which simplifies the communication procedure and improves the overall communication speed. . Figure 5 shows terminal equipment in communication equipment CE _A to CE _D.
This is a general flowchart showing the judgment and operation status by the TE, and is executed by a processor such as a microprocessor and memory provided in the terminal equipment TE. That is, by "initialize" 101,
A determination is made as to whether each communication device CE _A to CE _D will be a primary side with transmission rights or a secondary side without transmission rights, and a "primary side?" 102 determination is made according to the result. It will be done. Note that step 101 is performed when the power is turned on or the power supply recovers from a power outage. For example, a standby time is set for each communication device CE _A to CE _D according to its address number, and a signal is not received during this time. If not, it determines that it has the right to transmit, and if a signal from another is received, it determines that it does not have the right to transmit. If step 102 is Y (YES), the switch
After controlling the SW and performing “transmission mode setting” 111, a takeover signal “CP transmission” 112 is performed,
The signal “CP received?” 113 is used to monitor whether or not this is received via all transmission paths.
(NO) and the timer in the processor is set to “T _R elapsed?” 114 is N, Step 1 is executed.
After repeating steps 13 and subsequent steps, if step 114 becomes Y due to time-up of the timer, the process continues through step 112 through N of "Number of transmissions = M?" 115 until the maximum number of retransmissions M set by the counter in the processor is reached. Repeat the following and go to step 11
5 becomes Y, the process moves to "abnormality processing" 116, where an alarm is sent out and displayed. While step 115 is N, step 113 is Y.
If so, the validation signal "OK transmission" 121 is sent, and whether or not this is received via all transmission paths is monitored by the same signal "OK reception?" 122. While this is N, steps 114 and 115 are performed. 123 and N of " _Transmission count = M?" 124 for a certain period of time.
The following steps are repeated, and when step 124 becomes Y, the process moves to step 116. While step 124 is N, step 122 is Y.
If so, select the one with the highest priority among the transmission data it owns, and send a request signal with a code indicating this priority as "self-CT transmission" 131.
The signal "CT received?" 132 is used to monitor whether or not this is received via all the transmission paths.
Similarly, step 131 and subsequent steps are repeated via Y of ``T <sub>R</sub> elapsed'' 133 and N of ``transmission count=M?'' 134 for a certain period of time, and then the process moves to step 116 in response to Y of step 134. While step 134 is N, step 132 is Y.
If so, it is determined whether or not this is the one sent by the user using the "Self CT?" 135, and in response to Y of this, the validation signal "OK Send" 141 is sent, and the same signal is sent as in steps 122 to 124. While “OK received?” 142 is N, the “T _R elapsed?” is displayed for a certain period of time.
143 Y and “Number of transmissions = M?” 144 N
Step 141 and subsequent steps are repeated, and as step 144 becomes Y, step 11 is repeated.
Move to 6. While step 144 is N, step 142 is Y.
Then, when newly transmitted data is generated,
In order to check whether the priority of this is higher than the priority transmitted in step 131, "occurrence priority > transmitted priority?" 151 is determined, and data with the same priority is continuously transmitted. For this purpose, by comparing the highest priority among the other data to be transmitted and the priority transmitted in step 131, "Other highest priority = transmitted priority?" 152
If step 152 is N, steps 112 and subsequent steps are repeated to give other communication devices a chance to acquire the transmission right, while if step 151 is Y, steps 131 and subsequent steps are repeated and Notifies other communication devices that there is transmission data with a higher priority. When step 151 is N and step 152 is Y, "data transmission processing" 153 is performed, and steps 151 and subsequent steps are repeated, and until step 152 is N, the self-transmission data is sequentially sent from the highest priority to the highest priority. However, if a higher priority request signal CT is transmitted from another communication device and the result in step 135 is N, the mode shifts to a reception mode, which will be described later. In contrast to the above, when step 102 is N, the switch SW is controlled and the "reception mode setting" 161 is performed, and then the "transmission data available?" 16 is sent to the self.
Check 2, if this is Y, step 1
Same as 11 (transmission mode setting) 163, request signal from other communication device (CT reception?)
171 becomes Y, the priority between the self and the received one is set to "Self priority reception priority?" 17
2, and when this is N, it is determined that its own transmission priority is not equal to or lower than other transmission priorities and that it has the transmission right, and the process moves to step 131. Furthermore, if step 172 is Y, it is determined that it does not have the transmission right, and in step 171 it stores the received request signal CT as GLS in the buffer area of the memory (hereinafter referred to as BFM) by "BFM←CT" 181. , the contents of the BFM are transmitted as they are by “receive CT transfer” 182, and the process is performed in step 16.
As in 1, perform “receive mode setting” 183,
After performing "data reception processing" 184 and "monitoring processing" 185, steps 162 and subsequent steps are repeated. Therefore, in step 185, each communication device
Monitoring for CE _A to CE _D is repeated. FIG. 6 is a flowchart showing the details of step 153, and the question 201 is “Is the sending data GLS?”
If this is N, “data transmission” 20
However, when step 201 is Y, "GLS transmission" 211 is performed, and whether or not this is received via all transmission paths is monitored by "transmission GLS reception?" 212. , while this is N,
Similar to steps 114 and 115, the period “T _R
Progress? "Y of 213" and "Number of transmissions = M? ”2
Repeat steps 211 and after through 14 N;
In response to step 214 being Y, step 1
Similarly to 16, "abnormality processing" 215 is performed. While step 214 is N, step 212 is Y.
Then, as in steps 121 to 124, the activation signal "OK transmission" 221 and the same signal "OK reception?" 222 are sent for a certain period of time " _TR
Progress? ``Determination of 223, according to Y of this ``Number of transmissions = M? "Step 221 via N of 224
The subsequent repetitions are performed, and as step 224 becomes Y, the process moves to step 215. If an OK signal can be received while step 224 is N, step 222 becomes Y. FIG. 7 is a flowchart showing the details of step 184, and includes the question 301 “Is the received data GLS?”
If this is N, use “BFM for GLS”.
← After performing "Clear" 302, based on the address code, "Addressed to self?" ” 303, performs “content decoding” 304 according to Y, and repeats steps 301 and subsequent steps. Also, when step 301 is Y, the contents are the validation signal “OK?” ” 311, and if the result is N, “BFM←GLS” 312 determines BFM.
After storing GLS in step 301 and subsequent steps, as step 311 becomes Y via Y in step 301, check “BFM content available?” 321, and according to this Y, “BFM 322 is performed, and this determines whether the takeover signal is "CP?" 323, and if it is N, the process moves to step 304. In addition, response signal AS, end signal CD, confirmation signal
The CU, response request signal CS, etc. are performed during the general procedure of data transmission and reception. FIG. 1 is a flowchart showing details of step 185. In the memory of each terminal equipment TE,
A primary table and secondary table, which will now be described, are provided. In the tables below (Tables 1 and 2), A to D in the main table (hereinafter referred to as MT) and sub-table (hereinafter referred to as ST) correspond to each communication device CE _A to CE _D. In the data registered in , ○ represents a communicable state, and × represents a communicable state. Each communication device performs predetermined processing during a certain monitoring period using the method described below.
Each communication device can diagnose each communication device without any communication load. Each communication device is monitored at regular intervals, so a timer is set (step 411). When this monitoring timer starts, all registered ST data are marked with an X (step 412), and MT registered data is , you can leave it as before. The conditions at this time are shown in Table 1. However, when the communication system is initialized, that is, when the power is turned on, all MT registration data is set to × (step 401,
402).

[Table] After setting the timer (step 411) and setting all ST registration data to x (step 412),
From the determination of acquisition of the transmission right in FIGS. 5, 6, and 7 described above, it is known which communication device has acquired the transmission right. For example, when CE _i acquires the transmission right (step 421), The registered data corresponding to CE _i in the MT is referred to, and if the registered data is not x (N in step 422), the registered data corresponding to CE _i in the ST is set to 0 (step 433).
At this time, CE _i had acquired the transmission right during the previous monitoring period, and has acquired the transmission right this time as well. CE _i acquires the transmission right (Y in step 421),
When the registered data corresponding to CE _i in MT is x (Y in step 422), both the registered data corresponding to CE _i in MT and ST are set to 0 (step 431). This means that CE _i , which did not acquire the transmission right during the period, has acquired the transmission right during this period. In this case, since CE _i has recovered, that is, returned to a communicable state, a recovery notification is performed (step 432). In addition, it performs processing such as notifying recovery information and recording in memory that it can be selected as a communication partner. After performing these operations, does the certain period end (Y in step 441)?During this period,
For example, if CE _D becomes unable to communicate and CE _A recovers and becomes communicable, Table 1 changes to Table 2 below when the timer times up. In this way, since MT and ST have been changed, after the timer times up (Y in step 441),
Judgment processing (step 442) is performed to execute the contents of Table 3 below.

【table】

[Table] In other words, in the case of not responding (doing nothing), there is no change in the communication possible/disabled state both last time and this time, so nothing is done. MT is ○, ST is ×
In this case, communication was possible last time, but communication is not possible this time, so MT is set to x to notify that an abnormality has occurred, that is, it cannot be selected as a communication partner. This abnormality occurrence notification is displayed on a terminal display device, etc., and processing such as storing in a memory that the communication partner cannot be selected is executed. Through this third execution, the contents of MT are updated and become as shown in Table 4 below.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, at least a plurality of communication devices individually monitor the correctness or failure of each communication device depending on the acquisition status of transmission rights, so overall reliability is improved and the building Remarkable effects can be obtained in various registered data communications in which a large number of communication devices are connected in a loop, such as data communications between terminals of management equipment.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing the details of the monitoring process, Fig. 2 is a block diagram showing the configuration of each communication device, Fig. 3 is an overall block diagram, Fig. 4 is a diagram showing the transmission status of various signals, FIG. 5 is a general flowchart, and FIGS. 6 and 7 are flowcharts showing lower routines of FIG. 5. CE, CE _A to CE _D ...Communication equipment, S...Sending end,
R...Receiving end, SW, SW _A ~ SW _D ...Switcher, L _R
…Receiving side transmission line, L _S …Sending side transmission line, L ₁ ~
L ₄ ...transmission line.

Claims (1)

[Claims] 1. A plurality of communication devices are connected in a loop through a transmission path, and a communication device that requires a transmission right transmits a transmission right request signal by adding its own unique code, and in response to reception of the transmission right request signal. In a data communication method in which the other communication device determines that it does not have the transmission right, and the communication device that has transmitted the transmission right request signal acquires the transmission right, the communication device determines that it does not have the transmission right. Accordingly, the communication device that has acquired the transmission right is determined, and a code indicating each is registered in the sub-table corresponding to each communication device as the communication device that has acquired the transmission right as normal and the communication device that has not acquired the transmission right as abnormal. , determining whether each communication device is correct by comparing the contents of the sub-table with the contents of a main table in which results during the previous monitoring period are registered, and updating the contents of the main table with the contents of the sub-table; A data communication monitoring method characterized in that the above operations are repeated in at least a plurality of communication devices.