JPH06152612A - Polling control system - Google Patents

Abstract

PURPOSE:To attain quick restoration by preventing deterioration in the service for another terminal equipment and monitoring terminal equipments when a controller polls sequentially plural terminal equipments. CONSTITUTION:An ENQ is sent to a terminal equipment 7 not in fault by referencing a terminal state table 3 and a succeeding procedure is proceeded when an ACK (acknowledgement) or the like is sent. On the other hand, when no ACK (acknowledgement) or the like is received, a fault is set to the state terminal table 3 and a SUCCEEDING procedure is proceeded. Furthermore, the ENQ is sent to a terminal equipment 7 in fault by referencing the terminal state table 3 and a succeeding procedure is proceeded without awaiting a prescribed time, and when the. ACK or the like is sent, an EOT is sent at a succeeding polling, the terminal state table 3 is set to a normal state and the procedure is restored. On the other hand, when no ACK is sent, the transmission of the ENQ at a succeeding polling is repeated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polling control system for transmitting / receiving data to / from a plurality of terminals by polling.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
In a system in which a plurality of terminals (1) 24 are connected to the terminal (n) 24, the control device 21 is
It has been attempted to reduce the number of line control circuits 22 by sequentially communicating with the terminal 24 while switching lines without having an interface with the terminal 4.

In this case, the terminal 24 cannot transfer the data to the control device 21 by the contention method. That is, it is not known from the terminal 24 side whether the line control circuit 22 of the control device 21 is assigned to its own terminal 24. Therefore, data is transferred by the polling method.

When data is transferred from the terminal 24 to the control device 21 by this polling method, the terminal 24 receiving this ENQ responds to the ENQ from the line control circuit 22 of the terminal control device 21 with an ACK (response) or TEXT. Send (text data). At this time, x in FIG. 9B
As shown in FIG. 5, there is the following coping method for the terminal 24 that does not send ACK or TEXT.

(1) The polling of the terminal 24, that is, the transmission of ENQ is stopped from the next time. (2) Polling the terminal 24, that is, ENQ
Will continue to be sent after the next time.

The structure and operation of FIGS. 8 and 9 will be briefly described below. FIG. 8 shows a block diagram of the prior art. Figure 8
In, the control device 21 controls the plurality of terminals 2 via the line.
4 to send and receive data by sending and receiving data, and to provide a service, the line control circuit 22 and MPX / D
It is composed of an MPX (multiplexer / demultiplexer) 23 and the like.

The line control circuit 22 uses the MPX / DMPX2
3, the line (or line) is switched to transmit / receive data from a plurality of terminals (1) 24 to the terminal (n) 24 by the polling method.

The MPX / DMPX 23 is a terminal (1) 24.
To the terminal (n) 24. From terminal (1) 24 to terminal (n) 24
Is a terminal that communicates with the control device 21 via a line to receive a service.

The operation of the configuration of FIG. 8 will be briefly described with reference to FIG. FIG. 9A shows a polling procedure when the terminal 24 is normal. In FIG. 9A, S21
, The control device 21 transmits ENQ to the terminal (1) 24. The terminal (1) 24 sends an ACK or TEX in S22.
Send T.

In S23, the control device 21 transmits the ENQ to the terminal (2) 24. The terminal (2) 24 is A at S24.
Send CK or TEXT. In S25, the control device 21 transmits the ENQ to the terminal (3) 24. Terminal (3)
24 transmits ACK or TEXT in S26.

As described above, the terminal (1) 24, the terminal (2) 24, and the terminal (3) 24 sequentially send ACK or TEXT to the control device 21 in response to the polling from the control device 21, and a series of data is sent. Transfer. And
Data is transferred by polling repeatedly from the beginning.

FIG. 9B shows a polling procedure when a failure occurs in the terminal 24. In FIG. 9B,
In S31, the control device 21 transmits the ENQ to the terminal (1) 24. The terminal (1) 24 sends an ACK or T in S32.
Send EXT.

In S33, the control device 21 transmits the ENQ to the terminal (2) 24. Since a failure has occurred in the terminal (2) 24, nothing is transmitted in S34. The control device 21
The timer that was activated when the ENQ was sent in S23 is S3.
Since the time was over (TO) at 4, the terminal (2)
It is determined that there is no response due to some failure in 24, and the process proceeds to the next polling.

In step S36, the control device 21 transmits the ENQ to the terminal (3) 24. The terminal (3) 24 is A at S37.
Send CK or TEXT. As described above, the terminal (1) 24 and the terminal (3) 24 sequentially send ACK or TEXT to the control device 21 by polling from the control device 21, but the terminal (2) 2 in which the failure has occurred.
Since there is no response from 4, the control device 21 needs to wait until the time is over.

[0015]

In the coping method (1) described above, when the terminal 24 is restored, the polling from the control device 21 to the own terminal 24 is stopped.
There is a problem that the service cannot be provided from the control device 21 even if the device is restored. Therefore, it is necessary to notify the control device 21 that the terminal 24 has been restored by some operation.

Further, in the above-mentioned method (2), the terminal 24 waits for the transmission of ACK or TEXT from the terminal 24 until the terminal 24 recovers, detects the time-out after transmitting ENQ each time. However, there is a problem that the service of another terminal 24 is deteriorated because the next polling cannot be performed.

The present invention solves these problems.
When the control unit sequentially polls multiple terminals, a terminal status table that stores non-responding terminals and a status register that stores the status of the terminals are provided and operated to prevent deterioration of service to other terminals. Also, the purpose is to monitor the terminal and promptly perform recovery.

[0018]

[Means for Solving the Problems] Means for solving the problems will be described with reference to FIG. In FIG. 1, a control device 1 transmits / receives data to / from a plurality of terminals 7, and is composed of a line control circuit 2, an MPX / DMPX 4, and the like.

The line control circuit 2 is a circuit for controlling data exchange with a plurality of terminals 7 by polling, and has a terminal state table 3 and the like. The terminal status table 3 is for setting whether the terminal 7 is normal or faulty.

The terminals (1) 7 to (n) 7 perform data transmission / reception with the control device 1 via a line.

[0021]

According to the present invention, as shown in FIG. 1, the control device 1 refers to the terminal state table 3 and sends an ENQ to the terminal 7 which is not a failure, and the terminal 7 sends ACK or TEXT.
Is transmitted to the next terminal 7, while the terminal 7
When no ACK or TEXT is received after a lapse of a predetermined time, it is determined that the terminal 7 has a failure, the failure is set in the status terminal table 3 and the operation proceeds to the next terminal 7.
The control device 1 refers to the terminal state table 3 and sends ENQ to the faulty terminal 7, proceeds to the next terminal 7 without waiting for a predetermined time, and sends ACK or TEX from the terminal 7.
When T is sent, EOT at next poll
After transmitting (response corresponding to the transmission of ACK or TEXT), the terminal state table 3 is normally set and restored. On the other hand, when ACK or TEXT is not transmitted, the terminal 7 is transmitted to the terminal 7 at the next polling. The transmission of ENQ is repeated.

Further, the control device 1 refers to the terminal state table 3 and normally sets the terminal state table 3 when the break signal transmitted when the ENQ is not received from the faulty terminal 7 is in the space state. Then, it is restored and the process proceeds to the next terminal 7.

Further, the control device 1 refers to the terminal state table 3 and assigns DENQ (ENQ for diagnosis) to the faulty terminal 7.
Is transmitted, and the process proceeds to the next terminal 1 without waiting for a predetermined time, and when the ACK is transmitted from the terminal 7, the terminal state table 3 is normally set to recover.

Therefore, when the control device 1 sequentially polls a plurality of terminals 7, the status of the terminal status table 3 storing the non-responsive terminals 7 and the status of the terminals 7 are monitored to recover from a failure. It is possible to prevent deterioration of service to the terminal 7 and to promptly restore the terminal 7 by monitoring the terminal 7.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the construction and operation of an embodiment of the present invention will be sequentially described in detail with reference to FIGS.

FIG. 1 shows a block diagram of an embodiment of the present invention.
In FIG. 1, a control device 1 transmits / receives data to / from a plurality of terminals (1) 7 and (n) 7, and here, a line control circuit 2, an MPX / DMPX 4,
And a status display circuit 5 and the like.

The line control circuit 2 switches the MPX / DMPX 4 and connects it to the terminal (1) through a line (line).
7, the terminal (n) 7 is sequentially polled to control data transmission / reception, and the terminal status table 3 is internally provided to perform polling and the like with reference to the terminal status table 3.

The terminal status table 3 is a table in which the terminal (1) 7 to the terminal (n) 7 set and store a normal status or a failure status. The MPX / DMPX 4 is a multiplexer / demultiplexer and is used to connect a line to any one of the terminals (1) 7 to (n) 7.

The status display circuit 5 includes the terminal (1) 7
The state of the line of the terminal (n) 7 is detected from the above, and is held in the internal stator register 6 or the like.

The status register 6 holds the state of the line from the terminal (1) 7 to the terminal (n) 7. The state (level) of the terminals (1) 7 to (n) 7 held in the status register 6 is read by the line control circuit 2 via the internal bus.

The terminals (1) 7 to (n) 7 send and receive data to and from the control device 1 via a line. Next, the operation of the configuration of FIG. 1 will be described in detail with reference to the flowchart of FIG.

In FIG. 2, S1 determines the table of the target terminal. This is done by referring to the terminal status table 3 that the line control circuit 2 of FIG. 1 has internally to determine whether the polling target terminal 7 is normal or faulty. If it is normal, the polling process for the normal terminal 7 is performed in S2 to S4. On the other hand, in the case of a failure, the polling process for the terminal 7 in failure is performed in S5 to S8. This will be described below.

(1) Polling process for normal terminal 7: S2 sends ENQ. This is because the line control circuit 2 in FIG. 1 refers to the terminal state table 3 and finds that the terminal 7 to be transmitted is normal. Therefore, the MPX / DMPX 4 is switched to this terminal 7 and ENQ is transmitted via the line.

In step S3, the reception of data is awaited. This is S
The line control circuit 2 which has transmitted the ENQ in 2 transmits data (ACK (response) or TEXT
(Text data)). When data is received, the data (ACK or TE
XT) has been received, the series of polling ends. On the other hand, in the case of time-out (when the timer started at the time of sending the ENQ in S2 has timed out and cannot receive data even after a predetermined time has elapsed), the terminal state table 3 of the target terminal is set to a failure in S4. The fact that a failure has occurred in the terminal 7 is stored, and the next time is not waited until the time is over.

As described above, referring to the terminal status table 3, when the terminal 7 is normal, ENQ is transmitted and the terminal 7 responds to this by transmitting ACK or TEXT.
At this time, a failure occurs in the terminal 7 and an ACK or TEX
If T cannot be transmitted even after a predetermined time has elapsed and the transmission is over, a failure is set in the terminal status table 3, and from the next time onward, the polling process for the terminal 7 with the failure (2) described later is performed, and waits until the time is over. The failure is monitored, the recovery of the failure is monitored, the deterioration of the service to the other terminals 7 is prevented, and the recovery is promptly performed when the failure is recovered.

(2) Polling process for the faulty terminal 7: In S5, the status register 6 is read. Since this is found to be the faulty terminal 7 by referring to the terminal status table 3 due to the fault in S1, the contents of the status register 6 of this terminal 7 (ACK or TEXT in the latch in S25 of FIG. The bit "1" is set in response to the reception of the data, and the bit "0" is read when the data is not received. When there is data, that is, when either ACK or TEXT is received from the terminal 7 and "1" is set in the status register 6, the EOT is transmitted in S6 (ACK or TEXT).
After transmitting the EOT which is a response corresponding to the reception of XT) and completing the transmission process, the terminal state table 3 of the target terminal is normally cleared in S7, and it is confirmed that the terminal 7 has recovered from the failure. Set. As a result, the terminal 7 becomes normal at the next polling, and the normal processing of (1) is performed. On the other hand, when there is no data, that is, when neither ACK nor TEXT is received from the terminal 7 and “0” is set in the status register 6,
ENQ is transmitted in S8. Then, in response to this ENQ transmission (S23 in FIG. 3B), when the failure of the terminal 7 has been recovered, ACK or TEXT is transmitted, so this is received and the status register 6 displays " Set to 1 ”. As a result, at the next polling process, data is present in S5, EOT transmission is performed in S6, the terminal status table 3 is set normally in S7, and the normal process (1) is performed at the next polling process.

Next, a specific example in the configuration of FIGS. 1 and 2 will be described in detail with reference to FIG. FIG. 3 shows a specific example explanatory diagram (1) of the present invention. 3A shows the terminal 7
The following shows an example of failure.

In FIG. 3A, S11 is ENQ.
To send. This is because the control device 1 uses MPX / DMPX4
And the ENQ is transmitted to the terminal (1) 7 which is found to be normal by referring to the terminal status table 3.

In step S12, the terminal (1) 7 that receives the ENQ
Sends ACK or TEXT. Similarly, S13 transmits ENQ to the normal terminal (2).

In S14, a failure occurs in the terminal (2) 7,
Neither CK nor TEXT can be transmitted. S15 is a T.S. It becomes O (time over). This means that the timer started at the time of sending ENQ in S13 will time out. In response to the detection of this time-out, it is determined that the terminal (2) 7 that has transmitted the ENQ has a failure, and the terminal (2) 7 is set as a failure in the terminal status table 3.

Similarly, in S16, ENQ is transmitted to the normal terminal (3). In S17, the terminal (3) transmits ACK or TEXT. By the above, the terminal (2) 7
In response to the transmission of ENQ, a time-out occurs, and when this failure is detected, the terminal (2) 7 is set in the terminal state table 3 as a failure and stored.

FIG. 3B shows a polling procedure for the faulty terminal 7. In FIG. 3B, S
21, the control device 1 transmits ENQ to the normal terminal (1).

In S22, the terminal (1) sends an ACK or T
Send EXT. In S23, the control device 1 refers to the terminal state table 3 and transmits ENQ to the terminal (2) in failure, and then does not wait for the reception of ACK or TEXT,
Proceed to next S26.

In S24, since the terminal (2) in which the failure has occurred in S14 has been recovered by this time, ACK or TEXT is transmitted. In S25, the status display circuit 5 latches and stores the bit "1" in this terminal (2) of the status register 6 in response to the ACK or TEXT data transmitted in S24.

In S26, the control device 1 transmits ENQ to the normal terminal (3). In S27, the terminal (3) transmits ACK or TEXT. In S28, regarding the terminal (2) to which the control device 1 is going to poll, a failure is set in the terminal state table 3 in S15, and a bit "1" (data in S5 in FIG. 2) is set in the status register 6 in S25. Since it was found, the EOT is transmitted to the terminal (2) to end the series of transmission processing, and the terminal state table 3
To rewrite the fault of.

In S29, the control device 1 transmits ENQ to the terminal (2) at the next polling. In S30, the terminal (2) recovered from the failure transmits ACK or TEXT.

As described above, while the fault of the terminal (2) 7 is set in the terminal state table 3, the control device 1 is E
Although the NQ is transmitted to the terminal (2) 7, the process proceeds to the polling process of the next terminal 7 without waiting. At this time, the fact that the data was received when the ACK or TEXT was transmitted from the terminal (2) which was restored at this time is latched in the status register 6, and the EOT is set to the terminal in response to the latch at the next polling processing. (2) Send to 7 to end the transmission process and rewrite the fault in the terminal state table 3 normally. Further, at the time of the next polling processing, ENQ is transmitted to the terminal (2) 7, and the terminal (2) 7 ACKs or TEs.
It means that the XT is transmitted, the normal state is restored, and the restoration is completed.

Next, the configuration and operation of another embodiment of the present invention will be described in detail with reference to FIGS. this is,
Corresponding to the fact that the break signal is sent when the terminal (2) 7 recovers from the failure, the status register 6 is set to level H, and the failure of the terminal status table 3 is normally set based on this. It is another embodiment when returning to normal.

FIG. 4A shows a flowchart of the control device. In FIG. 4, S31 determines the table of the target terminal. This is done by referring to the terminal status table 3 that the line control circuit 2 of FIG. 1 has internally to determine whether the polling target terminal 7 is normal or faulty. If it is normal, the polling process for the normal terminal 7 is performed in S32 to S34. On the other hand, in the case of a failure, the polling process for the terminal 7 in failure is performed in S35 and S36. This will be described below.

(1) Polling process for normal terminal 7: S32 sends ENQ. This is because the line control circuit 2 in FIG. 1 refers to the terminal state table 3 and finds that the terminal 7 to be transmitted is normal. Therefore, the MPX / DMPX 4 is switched to this terminal 7 and ENQ is transmitted via the line.

In S33, the data reception is awaited. this is,
The line control circuit 2 that has transmitted the ENQ in S32 transmits the data (ACK (response) or TE
Wait for reception of XT (text data). When the data is received, the data can be normally received from the terminal 7, and the series of polling ends. On the other hand, in the case of time-out, the terminal state table 3 of the target terminal is set to the failure in S34, the fact that the failure has occurred in the terminal 7 is stored, and the next time is not waited until the time-out.

As described above, referring to the terminal status table 3, if the terminal 7 is normal, ENQ is transmitted and, in response, the terminal 7 transmits ACK or TEXT.
At this time, if a failure occurs in the terminal 7 and transmission is not possible even if the time is over, a failure is set in the terminal status table 3,
From the next time onward, the polling process for the faulty terminal 7 of (2) described later is performed so as not to wait until the time is over, the restoration of the fault is monitored, and the deterioration of the service to other terminals 7 is prevented. , To recover quickly when the failure is recovered.

(2) Polling process for the faulty terminal 7: In S35, the status register 6 is read.
Since this is found to be the faulty terminal 7 by referring to the terminal state table 3 due to the fault in S31, the contents of the status register 6 of this terminal 7 (b in S63 of FIG.
Bit "1" is set when the reak signal is at the H level (representing the state where the terminal 7 is normally recovered from the failure), and bit "0" is read when the signal is at the L level. In the space state, that is, when the H level of the break signal is received from the terminal 7 and "1" is set in the status register 6, the terminal state table 3 of the target terminal is normally cleared in S36. The recovery from the failure is set and the terminal 7 becomes normal, and the normal processing of (1) after S32 is performed. On the other hand, in the mark state, that is, when the L level of the break signal is received from the terminal 7 and "0" is set in the status register 6, it is determined that the failure of the terminal 7 is not recovered. , End without doing anything.

FIG. 4B shows a flowchart on the terminal side. In FIG. 4B, in S41, the ENQ reception time is over. This is because terminal 7 is
It is determined that the next ENQ is not yet received even if the timer is started after the NQ is received and the timer expires, that is, the control device 1 skips the ENQ transmission due to the failure of the terminal 7. (Failure of S31 in FIG. 4, mark state of S35).

In S42, since the ENQ reception time has expired in S41, a break is transmitted to notify the control device 1 that the failure of the terminal 7 has been recovered.
In response to the control device 1 receiving this break signal, the status register 6 becomes in the space state.

Next, a specific example in the configuration of FIGS. 1 and 4 will be described in detail with reference to FIG. FIG. 5 shows a specific example explanatory diagram (2) of the present invention. FIG. 5A shows the terminal 7
The following shows an example of failure.

In FIG. 5A, S51 is ENQ.
To send. This is because the control device 1 uses MPX / DMPX4
And the ENQ is transmitted to the terminal (1) 7 which is found to be normal by referring to the terminal status table 3.

In step S52, the terminal (1) 7 that has received the ENQ
Sends ACK or TEXT. Similarly, S53 transmits ENQ to the normal terminal (2).

In S54, a failure occurs in the terminal (2) 7,
Neither CK nor TEXT can be transmitted. S55 is a T.S. It becomes O (time over). This means that the timer started at the time of sending ENQ in S53 will time out. In response to the detection of this time-out, it is determined that the terminal (2) 7 that has transmitted the ENQ has a failure, and the terminal (2) 7 is set as a failure in the terminal status table 3.

Similarly, in S56, ENQ is transmitted to the normal terminal (3). In S17, the terminal (3) transmits ACK or TEXT. By the above, the terminal (2) 7
In response to the transmission of ENQ, a time-out occurs, and when this failure is detected, the terminal (2) 7 is set in the terminal state table 3 as a failure and stored.

FIG. 5B shows the polling procedure for the faulty terminal 7. In FIG. 5B, S
In 61, the control device 1 transmits ENQ to the normal terminal (1).

In S62, the terminal (1) sends an ACK or T
Send EXT. In S63, the control device 1 receives the H level of the break signal from the terminal (2) in which the failure is recovered, and sets "1" in the status register 6 (sets the space state).

In S64, the control device 1 subsequently transmits ENQ to the normal terminal (2). S65 is the EN of S64
The terminal (2) receiving Q sends ACK or TEXT.

In S66, the control device 1 transmits ENQ to the normal terminal (3). In S67, the terminal (3) transmits ACK or TEXT. By the above, the terminal (2)
While the fault 7 is set in the terminal state table 3,
The control device 1 skips the ENQ without transmitting it to the terminal (2) 7, and when the failure of the terminal (2) 7 is recovered and the H level (space status) of the break signal is received, the terminal status table 3 fails. From ENQ
Is sent, and the restored terminal (2) 7 sends ACK or TE.
It means that the XT is transmitted, the normal state is restored, and the restoration is completed.

Next, the configuration and operation of another embodiment of the present invention will be described in detail with reference to FIGS. 6 and 7. this is,
The DENQ is sent to the terminal (2) 7 having the failure and the ENQ is sent to the next terminal 7 without waiting, and when the ACK is received from the terminal (2) 7 which has received the DENQ, the status register 6 is latched. Incidentally, the ENQ is transmitted to the terminal (2) next time.

FIG. 6A shows a flowchart of the control device 1. In FIG. 6A, S71 determines the table of the target terminal. This is the line control circuit 2 of FIG.
It refers to the internal terminal status table 3 and determines whether the polling target terminal 7 is normal or faulty. If it is normal, the polling process for the normal terminal 7 is performed from S72 to S74. On the other hand, in the case of a failure, the polling process for the terminal 7 in failure is performed in S75 and S77. This will be described below.

(1) Polling process for normal terminal 7: S72 sends ENQ. This is because the line control circuit 2 in FIG. 1 refers to the terminal state table 3 and finds that the terminal 7 to be transmitted is normal. Therefore, the MPX / DMPX 4 is switched to this terminal 7 and ENQ is transmitted via the line.

A step S73 waits for data reception. this is,
The line control circuit 2 which has transmitted the ENQ in S72 transmits the data (ACK (response) or TE
XT) is received. When the data is received, the data can be normally received from the terminal 7, and the series of polling ends. On the other hand, in the case of time-out, the terminal state table 3 of the target terminal is set to the failure in S74, the fact that the failure has occurred in the terminal 7 is stored, and the next time is not waited until the time-out.

As described above, referring to the terminal status table 3, if the terminal 7 is normal, ENQ is transmitted, and in response to this, the terminal 7 transmits ACK or TEXT.
At this time, if a failure occurs in the terminal 7 and transmission is not possible even if the time is over, a failure is set in the terminal status table 3,
From the next time onward, the polling process for the faulty terminal 7 of (2) described later is performed so as not to wait until the time is over, the restoration of the fault is monitored, and the deterioration of the service to other terminals 7 is prevented. , When the failure is recovered, it will be promptly restored.

(2) Polling process for the faulty terminal 7: In S75, the status register 6 is read.
Since this is found to be the faulty terminal 7 by referring to the terminal state table 3 due to the fault of S71, the contents of the status register 6 of this terminal 7 (the contents held by the latch of S5 of FIG. 7B described later) ) Lead. If there is data,
That is, when ACK is received from the terminal 7 in response to DENQ and "1" is set in the status register 6, the terminal status table 3 of the target terminal is normally cleared in S76 to recover from the failure. By setting the above, the terminal 7 becomes a normal terminal, and the normal processing of (1) after S72 is performed.
On the other hand, when there is no data, that is, when ACK is not received from the terminal 7 and “0” is set in the status register 6, it is determined that the failure of the terminal 7 is not recovered ((b) of FIG. ) Indicates a flowchart on the terminal side.

In FIG. 6B, S81 is the terminal 7
Receives data. S82 is DENQ (EN for diagnosis
It is determined whether Q) has been received. If YES, DEN
Since Q is received, ACK is transmitted in S83 to notify that the terminal 7 has recovered from the failure. On the other hand, N
In the case of O, other processing is performed in S84.

Next, a specific example in the configuration of FIGS. 1 and 6 will be described in detail with reference to FIG. FIG. 7 shows a specific example explanatory diagram (3) of the present invention. FIG. 7A shows the terminal 7
The following shows an example of failure.

In FIG. 7A, S91 is ENQ.
To send. This is because the control device 1 uses MPX / DMPX4
And the ENQ is transmitted to the terminal (1) 7 which is found to be normal by referring to the terminal status table 3.

In step S92, the terminal (1) 7 that has received the ENQ
Sends ACK or TEXT. Similarly, S93 transmits ENQ to the normal terminal (2).

In step S94, the terminal (2) 7 fails and A
Neither CK nor TEXT can be transmitted. S95 is a T.S. It becomes O (time over). This means that the timer started at the time of sending ENQ in S93 will time out. In response to the detection of this time-out, it is determined that the terminal (2) 7 that has transmitted the ENQ has a failure, and the terminal (2) 7 is set as a failure in the terminal status table 3.

Similarly, in S96, ENQ is transmitted to the normal terminal (3). In S97, the terminal (3) transmits ACK or TEXT. By the above, the terminal (2) 7
In response to the transmission of ENQ, a time-out occurs, and when this failure is detected, the terminal (2) 7 is set in the terminal state table 3 as a failure and stored.

FIG. 7B shows a polling procedure for the faulty terminal 7. In FIG. 7B, S
1, the control device 1 transmits ENQ to the normal terminal (1).

In S2, the terminal (1) sends an ACK or TE.
Send XT. In S3, the control device 1 transmits DENQ (ENQ for diagnosis) to the terminal (2) whose failure has been recovered.

In S4, the restored terminal (2) transmits ACK. In S5, the control device 1 receiving the ACK sends the ACK
Is received and stored in the status register 6.

In S6, the control unit 1 sends ENQ to the normal terminal (3). In S7, the terminal (3) transmits ACK or TEXT. S8 transmits ENQ to the terminal (2) in which the failure is recovered. This is the terminal status table 3
As for the terminal (2) which is set as the failure in the status register 6, since "1" (data exists) is set in the status register 6 in S5, the data exists in S75 of FIG. After the table 3 is cleared normally, ENQ is transmitted to the terminal (2) in S72.

In step S9, the terminal (2) receives ACK or TE.
Send XT. As described above, while the fault of the terminal (2) 7 is set in the terminal state table 3, the control device 1
Sends DENQ (DENQ for diagnosis) to the faulty terminal (2) and proceeds to the next polling process without waiting. At this time, when ACK is transmitted corresponding to DENQ, "1" (with data) is set in the status register 6,
At the next polling process, the data of S75 is present and the terminal state table 3 is normally cleared and ENQ is transmitted in S76. As a result, the normal state is restored and the state is restored.

[0082]

As described above, according to the present invention,
When the control device 1 sequentially polls a plurality of terminals 7,
Since the terminal status table 3 for storing the terminal 7 having a failure and the status register 6 for storing the status of the terminal 7 are provided and operated to monitor the recovery of the terminal 7, the other terminals 7 can be operated. It is possible to prevent the deterioration of the service and to monitor the terminal 7 by polling and quickly recover. With these, (1) by sending ENQ to the faulty terminal 7 and proceeding to polling processing for the next terminal 7 without waiting, it is possible to prevent degradation of service to other terminals 7, and When ACK or TEXT is transmitted in response to ENQ, the fact is stored in the status register 6, and EOT transmission, ENQ transmission at the next polling,
ACK / TEXT transmission can be performed to restore a normal terminal, and the terminal 7 can be monitored to promptly recover.

(2) ENQ for the faulty terminal 7
By skipping the transmission of the message and proceeding to the polling process for the next terminal 7, it is possible to prevent the deterioration of the service to the other terminals 7, and at the same time, send the break signal from the terminal 7 which has recovered from the failure to the status register 6 To that effect, when the status register 6 is in the space state, ENQ transmission and ACK / TEXT transmission are performed to return to a normal terminal, and the terminal 7 can be monitored and quickly restored.

(3) DEN for the terminal 7 in which the failure has occurred
By sending Q (ENQ for diagnosis) and proceeding to polling processing for the next terminal 7 without waiting, it is possible to prevent degradation of service to other terminals 7 and to send an ACK corresponding to this DENQ. When that happens, the status register 6 stores that fact, and ENQ will be used at the next polling.
The terminal 7 can be quickly recovered by monitoring the terminal 7 by transmitting or ACK / TEXT and returning to a normal terminal.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a flowchart of the control device of the present invention.

FIG. 3 is a diagram (part 1) for explaining a specific example of the present invention.

FIG. 4 is a flowchart for explaining another operation of the present invention.

FIG. 5 is a diagram (part 2) for explaining a specific example of the present invention.

FIG. 6 is a flowchart explaining another operation of the present invention.

FIG. 7 is a diagram (part 3) for explaining a specific example of the present invention.

FIG. 8 is a configuration diagram of a conventional technique.

FIG. 9 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 1: Control device 2: Line control circuit 3: Terminal status table 4: MPX / DMPX 5: Status display circuit 6: Status register 7: Terminal

Claims (3)

[Claims] 1. A polling control system for transmitting and receiving data to and from a plurality of terminals by polling, wherein a control device (1) is provided with a terminal status table (3) for setting normality or failure of the terminal (7). (1) refers to the terminal status table (3), transmits ENQ for the terminal (7) which is not a failure, and when the terminal (1) transmits ACK or TEXT, the next terminal (1) is transmitted. On the other hand, when ACK or TEXT has not been received within a predetermined time from the terminal (7), it is determined that the terminal (7) has a failure and the status terminal table (3) is set as a failure and On the other hand, the control device (1) refers to the terminal state table (3) to transmit ENQ to the terminal (7) having the failure, and the next terminal (7) without waiting for the predetermined time. Go to 7) At the same time, when ACK or TEXT is transmitted from the terminal (7), EOT (response corresponding to transmission of ACK or TEXT) is transmitted at the next polling, and then the terminal state table (3) is set normally. And then recovered, while
A polling control method characterized in that, when ACK or TEXT is not transmitted, the ENQ is repeatedly transmitted to the terminal (7) at the next polling. 2. A polling control method for transmitting / receiving data to / from a plurality of terminals by polling, wherein a control device (1) is provided with a terminal status table (3) for setting normality or failure of the terminal (7), (1) refers to the terminal status table (3), transmits ENQ for the terminal (7) which is not a failure, and when the terminal (7) transmits ACK or TEXT, the next terminal (7) is transmitted. On the other hand, when ACK or TEXT has not been received within a predetermined time from the terminal (7), it is determined that the terminal (7) has a failure and the status terminal table (3) is set as a failure and On the other hand, the control device (1) refers to the terminal state table (3) and the break signal sent when the ENQ is not received from the faulty terminal (7). Polling control method in which the terminal status table (3) to recover by setting properly when was state, characterized by being configured to proceed to the next terminal (7). 3. A polling control system for transmitting / receiving data to / from a plurality of terminals by polling, wherein a control device (1) is equipped with a terminal status table (3) for setting normality or failure of the terminal (7), (1) refers to the terminal status table (3), transmits ENQ for the terminal (7) which is not a failure, and when the terminal (7) transmits ACK or TEXT, the next terminal (7) is transmitted. On the other hand, when ACK or TEXT has not been received within a predetermined time from the terminal (7), it is determined that the terminal (7) has a failure and the status terminal table (3) is set as a failure and On the other hand, the control device (1) refers to the terminal status table (3) to the terminal (7) having a failure and DENQ (EN for diagnosis).
Q) is transmitted, the process proceeds to the next terminal (7) without waiting for the predetermined time, and when the ACK is transmitted from the terminal (7), the terminal state table (3) is normally set and restored. A polling control method characterized by being configured to.