JPS61127248A - Network system equipped with communication circuit disconnecting location detect function - Google Patents

Abstract

PURPOSE:To detect surely a communication circuit disconnecting location by providing each terminal computer with setting means of a receiving waiting time which increases on a basis of priority set up in advance as well as with means to output a communication circuit disconnecting signal while there is no signal input within a receiving waiting time and the like. CONSTITUTION:Each terminal computer 31-315 sets an address number of hexadecimal notation: that is C1H, C2H, C3H...CFH respectively which are set to a host computer 1 together with number of 1-15 showing a priority to send the communication circuit disconnecting signal. Besides it, a receiving waiting time counting from 21 to 35 unit time interval is set to the each terminal computer 31-315, for example, by staggering its unit interval by one unit hour. And a CPU31 of each terminal computer 31-315 will count a time lacking in input by a time counter 35 and will output the communication disconnecting signal as well as address number when its count time reaches the receiving waiting time which is set respectively.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a communication line in which a plurality of terminal computers are connected to a host computer in a loop through one communication line, and the host computer controls each terminal computer. Related to a network system with a disconnection point detection function.

[Technical background of the invention and its problems] Conventionally, in this type of computer system, information output from the host computer is inputted to the host computer via each terminal computer. When the information received was not returned to the host computer, it was determined that the communication line was disconnected. However, this method has a problem in that even if it can detect a disconnection in the communication line, it cannot detect the location.

For this reason, the present inventors first installed a timer for counting reception waiting time that is reset and starts counting in response to the input of a signal in each terminal computer, and when the timer times up in each terminal computer, the communication line is disconnected. We have considered a system in which a signal is output together with an address number, and the host computer receives the communication line disconnection signal and the address number to detect a disconnection point in the communication line. (Refer to the specification and drawings of Japanese Patent Application No. 58-159251.) By the way, in such a computer system, when a new terminal computer is added between each terminal computer, A problem arises in which all reception waiting times set on the terminal computer must be reset. In other words, each terminal computer outputs a communication line disconnection signal when a signal input does not arrive within the reception waiting time, and the timing at which this signal is output is fixed according to the order of the terminal computers. Since the time is increased in increments, when another terminal computer is added in between, the reception wait time of that added computer is set to the reception wait time of the existing terminal computer that is one after that computer, and This is because it is necessary to shift the reception waiting time of the subsequent existing terminal computers by a fixed amount of time.

[Purpose of the Invention] This invention was made to solve these problems. Even if a terminal computer is added, there is no need to reset the reception waiting time, and the communication line It is an object of the present invention to provide a network system with a communication line disconnection point detection function that can reliably detect disconnection points.

[Summary of the Invention] This invention connects a plurality of terminal computers to a host computer in a loop via one communication line, sets an address for each terminal computer, and connects the terminal computers using address information from the host computer. In a network system in which the designated terminal computer and the host computer input and output information, each terminal computer has: a means for setting a reception waiting time that increases based on a preset priority; and a means for setting the reception waiting time. (a) The host computer is equipped with means for outputting a communication line disconnection signal together with its own address number when no signal is input within the reception waiting time set in . means for comparing the priority order of the terminal computer that outputs the signal with that of the terminal computer immediately preceding the terminal computer that has received the address number; (C) means for determining that the communication line between the previous terminal computer and the terminal computer that outputs the communication line disconnection signal is disconnected; In some cases, the terminal computer that outputs the communication line disconnection signal within the time difference between the reception wait time set for the previous terminal computer and the reception wait time set for the terminal computer that outputted the communication line disconnection signal. (d) means for checking whether or not a communication line disconnection signal is output from the previous terminal computer; means for determining that the communication line between the terminal computer and the terminal computer that outputs the communication line disconnection signal is disconnected; and (e) if the communication line disconnection signal is output as a result of the check by the above means, the communication line disconnection; A means/means for comparing the priorities of the terminal computer that outputs the signal and the terminal computer immediately before it is provided, and after the comparison process by the comparing means, the same processes as in (b) to (l) above are performed. By repeating this process, the location of a disconnection in the communication line is detected.

[Embodiments of the invention] Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a host computer 1 is connected to, for example, 15 terminal computers 31, 32, 33, .
is connected serially. The host computer 1 is provided with a central processing unit (CPLJ) 11, an interface 12, an optical transmission link optical transmission module 13, and an optical transmission link optical reception module 14. In addition, each of the terminal computers 31 to 3rs has a CPU.
31, an interface 32, an optical transmission link optical transmission module 33, an optical transmission link optical reception module 34, and a time counter 35 are provided.

The host computer 1 converts the parallel information output from the CPtJll into serial information using the interface 12, outputs it to the communication line 2 via the optical transmission module 13, and supplies it to the optical reception module 34 of the terminal computer 31. At the same time, the terminal computer 3
The serial information output from the optical transmitting module 33 of 15 to the communication line 2 is converted into parallel information by the interface 12 via the optical receiving module 14, and then sent to the CPU.
11.

The terminal computer 31 transmits information on the terminal computer 31 to the host computer 1 when transmitting the information flowing through the communication line 2 to the next stage terminal computer 32 as it is, and when executing a data transmission command with the corresponding address information. To accommodate both,
It is configured to logically OR the signal that directly transfers the signal flowing to the next stage terminal computer 32 in terms of hardware, and the signal that is sent to the host computer 1 by executing the data transmission command together with the corresponding address information. ,
This OR signal is supplied via the optical transmitting module 33 to the optical receiving module 34 of the terminal computer 32 at the next stage. Thereafter, information from the host computer 1 is processed in the same way as each terminal computer 32 to 315. The terminal computers j1 to j315 are CIH and C, respectively.
A hexadecimal address number 2H1C3H...CFI-1 is set, and this address number is set together with numbers (1) to (15) indicating the priority order for sending a communication line disconnection signal to the host computer 1. ing. That is, the terminal computer 31 has a priority of (1) and the address number is CIH, the terminal computer 32 has a priority of (2) and the address number is 02H, and the following priority and address numbers are set in the same way, and the last The terminal computer 315 has priority number (15) and address number CF)-1. In addition, each of the terminal computers 31 to 315 is provided with 21 to 35 units of time, respectively.
For example, the reception waiting time up to a unit time is set to be shifted by one unit time. That is, the terminal computer 3
1 is 21 unit time, terminal computer 32 is 22 unit time, terminal computer 33 is 23 unit time, and so on, increasing by 1 unit time, and the last terminal computer 1s is 3 unit time.
It is set to 5 units of time. Note that one unit time is determined by the processing power of the computer, and is on the order of several milliseconds to several tens of milliseconds.

As shown in FIG. 2, the CPU 31 of each of the terminal computers 31 to 315 counts the time with no signal input using a time counter 35, and when the counted time reaches the reception waiting time set for each, a communication line disconnection signal is issued. The 03H signal and address number are output. Note that if a signal is input before the count time reaches the reception waiting time, the time counter 35 is reset and restarted.

The CPU 11 of the host computer 1 sends address information CIH-CF to each terminal computer 31 to 315.
H is output sequentially at, for example, two unit time intervals. The various functions of the CPL 111 perform the processing shown in FIG.

That is, send the specified address to the terminal computer,
And performs reception processing of the transmitted address. As a result, it is checked whether the receiving address and the sending address match. If they match, specify the next address to send to and send again to the terminal computer. Further, if there is a mismatch, it is checked whether or not a 03H signal, which is a communication line disconnection signal, is received. If this communication line disconnection signal is received, the priority order of the terminal computer that sent the communication line disconnection signal is searched from a table stored in the internal memory. Next, compare the priority of the corresponding terminal computer with the priority of the previous terminal computer, and if the priority of the previous terminal computer is higher, the priority of the corresponding terminal computer and the previous terminal computer are compared. It is determined that the communication line between the two is disconnected.

In addition, when the priority of the previous terminal computer is lower, the difference between the reception waiting time of the corresponding terminal computer that sent the communication line disconnection signal and the reception waiting time of the previous terminal computer is calculated, and the difference is calculated. Set in memory as a timer. If a communication line disconnection signal is received from the previous terminal computer before the timer counts up, the priority order of the terminal computer that sent the communication line disconnection signal is stored in the internal memory again. Then, processing is performed to compare the priority order of the corresponding terminal computer with the priority order of the previous terminal computer. At this time as well, if the priority of the previous terminal computer is higher, it is determined that the communication line between the corresponding terminal computer and the previous terminal computer is disconnected. When the priority of the previous terminal computer is lower, the difference between the reception waiting time of the corresponding terminal computer that sent the communication line disconnection signal and the reception waiting time of the previous terminal computer is calculated, and the difference is stored in memory as a timer. In other words, when the priority of the previous terminal computer is lower, the generation of a communication line disconnection signal from that terminal computer is checked within one hour of the set timer, and the priority of the previous terminal computer is set. This process will be repeated until the computer has the highest priority.

In addition, if the priority of the previous terminal computer is lower and the communication line disconnection signal from that terminal computer does not occur within one hour of the set timer, the corresponding terminal computer and the previous terminal It is determined that the communication line with the computer is disconnected.

Therefore, for example, when the host computer 1 outputs address information C1H, the terminal computer 31 receives it and outputs an ACK code and predetermined information. Then, two units of time after outputting the previous address information C1H, the host computer 1 outputs address information C2H. Thus, the terminal computer 32 inputs data as shown in FIG. 4(a) to the optical receiving module 34. Then, the terminal computer 32 is connected to A as shown in FIG. 4(b).
Output the CK code and information. In this way, from now on, the host computer 1 updates the address information C3H every two units of time.
-CFH is output, and each terminal computer 33 to 3rs receives the corresponding address information and outputs an ACK code and predetermined information.

Therefore, the host computer 1 detects the presence or absence of input of the ACK code to enable each terminal computer 31 to
It is possible to detect whether or not 315 is operating normally. On the other hand, in each of the terminal computers 31 to 31s, the time counter 35 is reset and restarts the time counting operation every time various signals such as address information, ACK code, predetermined information, etc. are input. Therefore, when the communication line is working normally, the time counter 35 of each terminal computer does not count the set reception waiting time. However, for example, if a disconnection accident occurs in the communication line 2 between the terminal computer 31 and the terminal computer 32, no signals will be input to the subsequent terminal computers 32 to 315 including the terminal computer 32. Therefore, when 22 units of time have elapsed since the previous signal input, for example, the address information C1H specifying the terminal computer 31 as shown in FIG. 5(a), the time counter 35 of the terminal computer 32 is It counts 22 units of time, which is the reception waiting time, and outputs a communication line disconnection signal 03H and an address number C2H as shown in FIG. 5(b). After one unit of time has elapsed, the terminal computer 33 outputs a communication line disconnection signal 03H and an address number C3H. The host computer 1 then compares the priority of the terminal computer 32 that first outputted the communication line disconnection signal 03H with the priority of the terminal computer 31 immediately before it. As a result of this comparison, since the previous terminal computer 31 has a higher priority and a shorter reception waiting time, it can be determined that the old communication line between the terminal computers 31 and 32 has been disconnected. In this manner, when a disconnection accident occurs in the communication line while the 15 terminal computers 31 to 31s are connected, it is possible to detect not only the occurrence of the accident but also the location of the disconnection.

For such a computer system, two new terminal computers 31s and 3t are added as shown in FIG.
If y is added, these two terminal computers 3s
s, 3t 7 address number DOH, D1H1 priority (1B) (17), reception waiting time 36
Set to unit time and 37 unit time, respectively. And the host computer 1 has these two terminal computers 3
16.317 is installed between the terminal computer 32 and the terminal computer 33.

In this way, for example, if the communication line 2 between the terminal computer 32 and the terminal computer 316 is disconnected, the terminal computer 33 will first send the communication line disconnection signal 03H and the address 23 units of time after the disconnection. Number C3H is output. This is because the reception waiting time is the shortest among those behind the location where the disconnection occurred. Therefore, the host computer 1 compares the priority order with the previous terminal computer 317. As a result, it is found that the priority of the previous terminal computer 317 is lower, so the host computer 1 next uses the reception waiting time 37 unit time set for the previous terminal computer 317 to The reception waiting time of the computer 33 is processed by subtracting 23 units of time, and within the resulting 14 units of time, the communication line is disconnected from the terminal computer in front of the computer 33, that is, either 317.31ts or 32.3t. Check whether there is a signal output.

Then, after about 13 units of time, terminal computer 316
A communication line disconnection signal 03H and an address number DOH are output from. As a result, the host computer 1 determines that a disconnection accident has occurred before the terminal computer 316, and compares the priorities of the terminal computer 316 and the previous terminal computer 32. As a result, the previous terminal computer 32 has a higher priority, so the host computer 1
16 is determined to be disconnected.

In this way, even if a new terminal computer is added on the way, not only the disconnection of the communication line 2 but also the location of the disconnection can be reliably detected. Further, even if a terminal computer is added, there is no need for troublesome work such as setting the reception waiting time of the terminal computers 33 to 31s later than the installed position of the added terminal computer. Then, it is sufficient to simply store the installation position of the added terminal computer in the host computer 1. In this way, a new terminal computer can be added without changing the information set in the existing terminal computers 31 to 315, and a disconnection point in the communication line 2 can be reliably detected.

In the above embodiment, two terminal computers were added, but the number of terminal computers is of course not limited to this.

[Effects of the Invention] As detailed above, according to the present invention, even if a terminal computer is added, there is no need to reset the reception waiting time, and the disconnection point of the communication line can be reliably detected. Accordingly, it is possible to provide a network system with a communication line disconnection point detection function.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention. Fig. 1 is a block diagram before adding a new terminal computer, Fig. 2 is a flowchart showing the main processing of CPIJ of the terminal computer, and Fig. 3 is a host computer. FIG. 4 is a waveform diagram showing the relationship between input signals and output signals to the terminal computer, FIG. 5 is a waveform diagram showing the disconnection detection operation of the communication line of the terminal computer, and FIG. FIG. 6 is a block diagram when a new terminal computer is added. 1... host computer, 2... communication line, 31
~31s...Existing terminal computer, 31B, 31
7...Added terminal computer, 11.31...
CPU (central processing unit), 35... time counter. Applicant's agent Patent attorney Takehiko Suzue Figure 2

Claims (1)

[Scope of Claims] A plurality of terminal computers are connected to a host computer in a loop via one communication line, and an address is set for each of the terminal computers, and the terminal computers are controlled by address information from the host computer. In a network system in which the designated terminal computer and the host computer input and output information, each terminal computer includes: a means for setting a reception waiting time that increases based on a preset priority; Means is provided for outputting a communication line disconnection signal together with its own address number when no signal is input within the reception waiting time set by the setting means, and the host computer is configured to: (a) communicate from each terminal computer; means for comparing the priority order of the terminal computer that outputs the signal with the previous terminal computer when receiving the line disconnection signal and address number; means for determining that the communication line between the previous terminal computer and the terminal computer that outputs the communication line disconnection signal is disconnected when When the ranking is lower, the communication line disconnection signal is sent within the time difference between the reception waiting time set for the terminal computer immediately before it and the reception waiting time set for the terminal computer that outputs the communication line disconnection signal. means for checking whether or not a communication line disconnection signal is output from a terminal computer preceding the terminal computer that outputs the terminal computer, and (d) if a communication line disconnection signal is not output after checking by this means means for determining that the communication line between the previous terminal computer and the terminal computer that outputs the communication line disconnection signal is disconnected; and (e) if a communication line disconnection signal is output as a result of the check by the above means; is provided with a means for comparing the priorities of the terminal computer that outputs the communication line disconnection signal and the previous terminal computer, and after the comparison process by the comparison means, the same steps as in (b) to (e) above are performed. A network system with a communication line disconnection detection function, which detects a communication line disconnection by repeating processing.