JPH11259782A - Status change transmission system for ras data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission system which surely reports RAS information to a destination station by status change transmission. SOLUTION: A local station transmits status change RAS data to the destination station as RAS information, and the destination station transmits response RAS data as a response to it. The local station transmits RAS data again when a response doesn't come within a certain time after transmission of status change RAS data. The number of times of transmission of status change RAS data is stored, and the local station transmits RAS data again also if responses whose number corresponds to the number of times of transmission don't come from the destination station within a certain time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a communication system for transmitting information between transmission control devices, and more particularly, to a RAS data transmission system in a transmission device.

[0002]

2. Description of the Related Art In a plant, a remote monitoring control system for automation and labor saving of a wide area system such as electric power, water and sewage, gas, traffic, and environmental monitoring is indispensable for centralized management.

In this remote monitoring system, a plurality of transmission control devices are connected to a network, and commands and information for plant management are exchanged between the transmission control devices. There are two types of data transmission schemes: fixed-cycle transmission and state-change transmission.

FIG. 10 is a diagram for explaining these methods. When data is transmitted from the transmission device A to the transmission device B in a configuration in which the transmission device A and the transmission device B are connected by a line as shown in FIG. 10A, a fixed period shown in FIG. In the case of the transmission method, data is transmitted periodically at a constant transmission interval. In the case of the state change transmission system shown in FIG. 10C, data is transmitted only when the information content to be transmitted from the transmission device A to the transmission device B changes.

In the case of fixed-cycle transmission, if the transmission interval is set short, the same data will be transmitted a plurality of times.
The reliability of the transmission is higher than the state change transmission. However, since the occupancy rate of the transmission path increases and the same data is transmitted a plurality of times, the transmission efficiency is low.

Therefore, in the transmission device of the remote monitoring system,
Measurement data and the like whose values change in real time are transmitted by periodic transmission, and control data and the like whose values change only at a specific time are transmitted by state change transmission. In addition, RAS (Reliability, Availability, S
erviceability) Information is transmitted using periodic transmission to increase reliability.

[0007]

The RAS information, which is information for improving the reliability of the system, is one of the most important transmission data in the whole system, and therefore, is set to ensure that the data is transmitted. The transmission is performed using periodic transmission, the transmission priority is set to the highest, and the transmission interval is set to the shortest time. So this R
The RAS data for notifying the AS information occupies a considerable weight in all the transmission data flowing on the transmission path. Therefore, contention between control data transmission and RAS data transmission frequently occurs. At this time, transmission of control data having a low priority is awaited, and as a result, the processing capability of the entire control system is reduced.

[0008] The RAS information indicates a change in the cause of a failure in the system (failure occurrence / recovery). This state changes very rarely in view of the operating time of the system. Therefore, when RAS data is transmitted periodically,
Since the same data is frequently transmitted, the transmission efficiency is extremely poor.

The present invention has been made in consideration of the above problems, and has as its object to provide a transmission system that enables reliable transmission to a partner device when the state of RAS information changes.

[0010]

SUMMARY OF THE INVENTION A transmission apparatus according to the present invention is presumed to be used in a station in a remote monitoring and control system, and includes RAS data transmission means and response RAS data reception means.

[0011] The RAS data transmitting means, when there is a change in the RAS information of the first station using the transmission device, the RAS data transmission means
The RAS data including the S information is transmitted to a second station in the remote monitoring control system.

The response RAS data receiving means receives the second RAS data from the second station as a response to the changed RAS data.
Response RAS data including the RAS information of the other station.
The state-changed RAS data and the response RAS data include, for example, header information for distinguishing the state-changed RAS data from the response RAS data.

[0013] If there is no response from the second station within a certain period after the transmission of the state-changed RAS data by the RAS data transmitting means, for example, the RAS data transmitting means returns the state to the second station. Transmit the modified RAS data.

Further, the transmission apparatus according to the present invention may be configured to further include RAS data transmission number management means. This RAS data transmission number management means is provided with the above-mentioned state change R
After a lapse of a certain period from the latest transmission of the AS data, if the number of responses from the second station to the changed RAS data is smaller than the number of times of transmission of the changed RAS data, the RA
The S data transmitting means transmits the RAS data to the second station again.

The present invention also includes a method for transmitting RAS information between stations in a remote monitoring control system. in this case,
The first station, when its own RAS information changes,
The state change RAS data including the S information is transmitted to the second station, and the second station that receives the state change RAS data transmits the state change RAS data to the second station.
Transmitting response RAS data including the RAS information of the second station to the first station as a response to the S data, wherein the first station receives the response RAS data from the second station, It confirms that the status change RAS data transmitted by itself has been notified to the second station.

According to the present invention, even if the RAS data of the first station is transmitted by the RAS transmission of the first station when the RAS information of the first station is changed, the first station transmits the RAS data of the first station. Whether or not the transmitted RAS data has been transmitted to the second station can be determined based on whether or not the response RAS data is transmitted as a response to the data.

Further, when the configuration change RAS data is transmitted again when there is no response to the status change RAS data, the RAS information is reliably transmitted to the second station. Further, when the RAS data transmission number management means is provided, the latest RAS information can be reliably transmitted to the second station.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of the present invention, transmission of RAS data performed by MTCA, which is one of transmission devices used in a remote monitoring system, will be described below.

MTCA (MICREX Tele-Communication Ad)
apter) is a product made by Fuji Electric that aims to simplify system maintenance and management, improve driving operability, and enhance operation management information in response to the expansion of communication services accompanying the liberalization of lines and the spread of FA and PA. Transmission device. In MTCA, in order to meet the demand for high-speed transmission of large amounts of data, HDLC (High Level
Data Link Control procedure) is adopted.

By connecting this MTCA as a transmission device to a controller for controlling each device in the plant via a network, a transmission monitoring system of small to medium scale can be configured.

FIG. 1 is a diagram showing an example of the system configuration. The MTCA is a transmission device applied as a master station or a slave station of a 1: 1 system, and has a function related to communication in the system. As shown in FIG. 1, the master station 10 and the slave station 20 are connected by a telephone line or a private dedicated line 30 by MTCAs 11-1 and 11-2, respectively.
In 0 and the slave station 20, the MTCAs 11-1 and 11-2
And measuring instruments and switches 40-1 and 4 in the plant
0-2 are controlled by M
P / PE link 13- which is the standard control LAN of TCA
1, 13-2.

When any failure (RAS factor) occurs in the slave station 20, RAS data specifying the RAS factor is transmitted from the slave station 20 to the master station 10, and the master station 10 determines the RAS data based on the received RAS data. Display and notification (alarm) to the operator, and when the system scale is large, the location is specified. As a result, maintenance for trouble factors such as replacement and repair can be performed quickly, and the system can be quickly restored.

Hereinafter, as an embodiment of the present invention, a case will be described in which the RAS data can be reliably transmitted to the partner station by the state change transmission in the system as shown in FIG.

In the following description, a system having a configuration in which a master station and a slave station are connected 1: 1 as shown in FIG. 1 will be described for simplification of description, but the present invention is not limited to this. It is also possible to adopt a configuration in which a station uses a transmission device capable of connecting to a plurality of slave stations.

The timing for transmitting RAS data in the present system is as follows: at the time of initial start, when the state of the RAS factor changes and the value of the RAS data changes,
There are three cases when the transmission is recovered from the transmission impossible state (modem abnormality, line disconnection, traffic congestion, etc.).

First, a description will be given of the case of the initial start, which is the activation of the apparatus by turning on the power or resetting. FIG. 2 is a diagram illustrating a case where RAS data is transmitted as one of the initialization processes at the time of initial start.

As one of the initial processes, the own station that has performed the initial start sends an H signal to the partner station that is the transmission partner.
Asynchronous balanced mode (A
SABM which instructs to set up communication by BM)
Send a command. And own station is this SA than the other station
When a UA response indicating that the SABM command has been accepted is received as a response to the BM command, RAS data is transmitted next. Note that the MTCA has a specification in which data cannot be transmitted immediately after the initial start. Therefore, the transmission of the RAS data is performed 30 seconds after the reception of the UA response.

Next, transmission of RAS data when a change occurs in RAS factors such as occurrence / recovery of a failure and a corresponding change in RAS data will be described. Figure 3 shows RA
It is a figure which shows transmission of RAS data when a change occurs in the RAS factor in S information.

When a minor failure such as a P / PE link device abnormality occurs, a change occurs in the state of the RAS factor,
When the value of the RAS information changes accordingly, the station transmits RAS data including the RAS information to a specific partner station.

In the case of FIG. 3, if any trouble occurs,
The own station transmits the RAS data changed by the failure to the other station. In addition, the failure is recovered, and RA
When the value of the S information changes, the own station transmits RAS data to the other station again. At this time, if there is a further change in the RAS factor before the transmission of the RAS data (for example, recovery immediately after the occurrence of a failure), the own station transmits the RAS data including the latest RAS information only once.

FIG. 4 shows a RAS having a 1W (word) configuration.
FIG. 3 is a diagram illustrating a configuration of information. In the configuration of FIG. 4, one bit is assigned to each RAS cause, and each bit is 0 or 1, indicating the state of the corresponding RAS cause. For example, in the RAS information shown in FIG. 4, the bit 9 is a minor MTCA failure, and the bit 14 (EH) is a PE.
The P / PE link error is associated with the link duplication abnormality, bit 15 (FH) as a RAS cause, and when a failure occurs in these RAS causes, the corresponding bit includes RAS information in which 1 is set. The RAS data containing the RAS information whose corresponding bit is reset to 0 upon recovery from the failure is transmitted to the partner station every time the state of the RAS factor changes.

Finally, transmission of RAS data when recovery from a transmission impossible state such as a modem abnormality, line disconnection, line congestion, etc. will be described. FIG. 5 is a diagram showing transmission of RAS data at the time of recovery from a transmission impossible state.
The S data is transmitted when the own station recovers from the transmission impossible state as shown in FIG. 5A and transmits the RAS data to the partner station. In some cases, the own station transmits RAS data to the partner station that has started.

In the case of FIG. 5 (a), when the transmission is restored from the above transmission disabled state, the own station immediately transmits RAS data to the other station to notify that the line has been restored and transmission is possible.

In the case of FIG. 5B, the partner station is in a transmission disabled state for some reason, so that even if the own station transmits the SABM command, no response is returned. In this case, the own station continues to transmit the SABM command many times until there is a response from the partner station. Then, after the partner station performs an initial start and restores transmission, a UA response is transmitted as a response to the SABM command from the own station to establish communication in the asynchronous balanced mode between the two stations. Send

As described above, in this embodiment, even when one station is in a communication disabled state, RAS data is reliably transmitted to the partner station immediately after the line is restored. Next received RA
The response to the S data will be described.

In this embodiment, the receiving station that has received the RAS data returns RAS data including its own RAS information to notify the transmitting station that the RAS data has been received.

In the following description, in order to distinguish the two RAS data, the RAS data transmitted when a RAS data transmission factor occurs, such as when the RAS factor has changed, has been described above. RAS data, status change RA
The RAS data returned from the station that has received the S data to the source of the state-changed RAS data as a response is called response RAS data.

FIG. 6 (a) shows that the own station, which has received state change RAS data from the partner station, sends a response RA to the partner station as a response.
It is a figure explaining the case where S data is returned. A RAS data transmission factor such as a change in the RAS factor occurs at the partner station,
When the state-changed RAS data is transmitted, the own station receiving the RAS data transmits response RAS data indicating that the RAS data has been received from the partner station as a response thereto. Upon receiving the response RAS data, the partner station confirms that the own station has received the state-changed RAS data transmitted by itself.

As described above, when the partner station returns the response RAS data to the transmission of the state-change RAS data, the transmitting station that has transmitted the state-change RAS data transmits the response RAS data to the state-change RAS data. It is possible to determine whether or not the state-changed RAS data has been reliably transmitted to the partner station based on whether or not a reply has been received.

The response RAS data and the change RAS data have different data structures. Change RAS data to RA
The reason why the S data and the response RAS data have different configurations is that there is a case where the own station cannot receive the RAS data of the partner station in the case of FIG. 6B.

FIG. 6B shows a case where the partner station transmits RAS data, and the own station which has received the RAS data is reset for some reason before returning a reply to the partner station. Performs an initial start, establishes communication with the partner station by transmitting a SABM command and receiving a UA response that is a response thereto, and then transmits RAS data to the partner station as one of the initial processes at the initial start as described above. Send.

When the state-changed RAS data and the response RAS data have the same configuration, in the case of FIG. 6B, the RAS data transmitted from the partner station to the own station disappears with the reset of the own station. Nevertheless, the partner station receiving the RAS data by the initial start from its own station considers this to be a response to the RAS data transmitted by itself, and thus determines that its own RAS data has been transmitted to its own station.
Processing such as retransmission of S data is not performed. Therefore, the RAS data of the other station is not transmitted to the own station.

To avoid this, in the present embodiment, the response R
The AS data and the change RAS data have different data configurations. FIG. 7 is a diagram showing an example of the data configuration of the information RAS and the response RAS. FIG. 7A shows the information frame configuration of the HDLC, and FIG. 7B shows an example of the configuration of the information field in the information frame. Things.

The status change RAS data and response RAS data are transmitted in the form of an HDLC information frame. As shown in FIG. 7A, this HDLC information frame includes a flag F (8 bits), an address field A (8 bits), a control field C (8 bits), an information field I (8 × N bits), The configuration includes error control information FCS (16 bits). The flag F indicates the start and end of this frame and is a bit string for synchronizing frames between transmission and reception. The address field A is an address for designating the transmission destination of the frame, the control field C is for designating the contents of the command or response of the frame, and the error control information FCS is a CRC (cyclic redundancy check) code of the frame used for error control. .

The information field I is an N-byte (N = 10 in this embodiment) long field in which the information content transmitted by this frame is stored. In this embodiment,
As shown in FIG. 7B, this information field includes a 4-byte header portion and an ECC which is the inverted data of the header portion.
A two-byte RAS information as shown in FIG.

The header section stores control information, and includes FC (Function Code) indicating packet function contents, HL (Header Length) indicating header length, DL (Data Length) indicating data packet length, It is composed of the sequence number NO (Number) of the data packet. Among them, in the present embodiment, the value of the sequence number NO is changed to the state change R
Different values are set in the AS data and the response RAS data to distinguish them. In the case of FIG. 7B, 00H is set to the state change RAS and 01H is set to the response RAS to the sequence number NO. The MTCA, which is the transmission device of each station, refers to the sequence number NO to make the received RAS data
It identifies S data or response RAS data.

The ECC section is used for error checking of data on the receiving side. When the data in the header section does not match the data in the ECC section, that is, when the value in the header section is compared with the ECC section,
If the value does not become 0H when exclusive OR is performed with the value in the unit, the receiving station discards this data.

By having the above-described configuration of the RAS data and the response RAS data, the station that has received the RAS data can reliably identify whether the RAS data is the RAS data or the response RAS data. It is also possible to detect transmission errors.

Next, the retry function will be described. The transmission device according to the present embodiment has a retry function of transmitting state change RAS data again when response RAS data is not returned from a destination within a predetermined period after transmitting state change RAS data.

FIG. 8 is a diagram for explaining the retry function. The own station that has transmitted the state change RAS data to the partner station sets 1 to a system variable F and waits for a response from the partner station.
This system variable F is a variable for counting the number of times of transmission of the state-changed RAS data.

Normally, the state-changed RAS data is transmitted to the partner station, and the partner station returns response RAS data as a response. The own station receiving this response RAS data is
Recognizing that the S information has been transmitted to the partner station, subtract 1 from the variable F.

However, the state-changed RAS data transmitted by the own station is not transmitted to the partner station for some reason, or even if the partner station receives the state-changed RAS data, the state becomes abnormal before the response to the RAS data or the line is changed. The response RAS data may not be able to be returned for some reason such as disconnection. At this time, the response RAS data is not returned to the own station. In this case, the local station checks the value of the variable F, and if the variable F remains 1 after a certain period (10 seconds in FIG. 8) has elapsed after transmitting the status change RAS data, that is, the transmitted status change RAS If no response RAS data is returned from the partner station, the state change RAS data is transmitted to the partner station again. In addition, by transmitting the state-changing RAS data at regular time intervals, even when the partner station supports only periodic transmission,
Communication compatibility can be ensured.

The partner station returns the response RAS data if it has recovered from the abnormality at the time of retransmission of the state-changed RAS data. Upon receiving this, the own station subtracts 1 from the variable F and resets F to 0. If the other station has not yet recovered at the time of this retransmission, there will be no response from the other station, so the own station will further change the state after a certain period (10 seconds) from the retransmission.
The AS data is transmitted to the partner station.

As described above, the station that has transmitted the state-changed RAS data receives the response RAS data from the destination station and receives the state-changed RAS data.
Until it is confirmed that the S data has been transmitted to the partner station,
Since the state-changed RAS data is transmitted repeatedly, the state-changed RAS data is reliably sent to the partner station. Therefore, even in the case of state change transmission, RAS information can be reliably transmitted to the partner station.

Next, management of the number of times of transmission of RAS data will be described. For example, the state of the RAS factor changes immediately after transmitting the state-changed RAS data, and the state-changed RAS data is transmitted a plurality of times before receiving the response RAS data from the partner station, such as transmitting the state-changed RAS data again. Sometimes. In this case, even if the station that has transmitted the state-changed RAS data receives the response RAS data from the partner station, the station that has received the state-changed RAS data, that is, the latest state-changed RAS data transmitted by itself, I can't confirm if I received it. In the present embodiment, in such a case, the number of transmitted state-change RAS data is stored, and if there is no response for the number of times of transmission, the state-change RAS data is re-transmitted.
It has a function of managing the number of RAS data transmissions for transmitting data.

FIG. 9 is a view for explaining the transmission data number management function. In FIG. 9, it is assumed that the own station immediately recovers from the minor failure after transmitting the state-change RAS data due to the occurrence of the minor failure, and transmits the state-change RAS data indicating the fact again. In this case, every time the state-changed RAS data is transmitted, the number of transmissions is incremented by +1 to the system variable F that counts the number of times the state-changed RAS data is transmitted, and 1 is added in the first transmission, and 1 in the second transmission. 2 is set in the variable F as the number of times of transmission of the state change RAS data.

After transmitting the latest (the second time in FIG. 9) state-changed RAS data, the own station waits for a response from the partner station for a certain period (10 seconds in FIG. 9). If the other station is operating normally, the number of times the state change RAS data has been received from the own station (FIG. 9)
(2 times in the case of) The response RAS data is transmitted as the response. Then, each time it receives it, its own station subtracts the number of transmissions from the variable F by one. When response RAS data for all state-changed RAS data is received, the variable F
Is 0.

However, for some reason, the partner station may not be able to transmit the response RAS data in response to the status change RAS data. In the case of FIG. 9, it is assumed that after transmitting response RAS data as a response to the first state-changing RAS data, the partner station cannot respond to the second state-changing RAS data due to an abnormality or the like. In this case, the variable F of the own station becomes F ≧ 1, and the own station checks the value of this variable F after a lapse of a fixed period from the transmission of the last state-change RAS data, so that You can judge whether you got a response. And if F
If ≧ 1, that is, if all responses to the changed RAS data have not been received from the partner station, the own station retransmits the changed RAS data to the partner station. In the case of FIG. 9, since F = 1, the own station sends the state-changed RAS data to the partner station again. In this case, since the retransmission is performed, the value of F remains at 1 without being updated. As the RAS information in the re-transmitted state-changed RAS data, the latest RAS information indicating the state of the RAS factor at the time of the retransmission is transmitted.

The retransmission of the state-changed RAS data is performed until F = 0, that is, until all the responses to the transmitted state-changed RAS data are received from the partner station. This allows
The own station can surely notify the other station of the latest RAS information.

[0060]

As described above, according to the present invention, even if the status change transmission for transmitting the status change RAS data is performed when the RAS information is changed, the response RAS data is returned as a response to the status change RAS data. It can be determined whether or not the state-changed RAS data has been transmitted to the other station, based on whether or not is transmitted from the other station.

When the response to the state-changed RAS data from the partner station is not received, the state-changed RAS data is transmitted to the partner station again, so that the RAS information is reliably transmitted to the partner station. Furthermore, since the number of times of transmission of RAS data can be managed, the latest RAS information can be reliably transmitted to the partner station.

As described above, according to the present invention, R
Since the state change transmission of the AS information can be realized, the occurrence rate of contention between the RAS data and other data in the system such as control data is lower in each stage than in the periodic transmission. Therefore, other data in the system does not suffer from transmission failure due to contention with the RAS data, thereby improving the transmission efficiency and processing capacity of the entire system.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a system configuration based on MTCA.

FIG. 2 is a diagram showing transmission of RAS data at the time of an initial start.

FIG. 3 is a diagram illustrating an RA when a change occurs in a factor of RAS information;
It is a figure showing transmission of S data.

FIG. 4 is a diagram illustrating a bit configuration of RAS information.

FIG. 5 is a diagram showing transmission of RAS data at the time of recovery from a transmission impossible state.

FIG. 6 is a diagram illustrating a case where a local station that has received state-changed RAS data from a partner station returns response RAS data to the partner station as a response.

FIG. 7 is a diagram illustrating an example of a data configuration of a state change RAS and a response RAS.

FIG. 8 is a diagram illustrating a retry function.

FIG. 9 is a diagram illustrating management of the number of times of state-change RAS data transmission.

FIG. 10 is a diagram illustrating fixed-cycle transmission and state-change transmission performed between transmission control devices.

[Explanation of symbols]

 Reference Signs List 10 master station 11 MTCA 12 controller 13 P / PE link 20 slave station 30 line 40 device

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04Q 9/02 H04L 13/00 307Z

Claims (5)

[Claims] 1. A transmission device used in a first station in a remote monitoring and control system, wherein when the RAS information of the first station changes, the RAS is changed.
RAS data transmitting means for transmitting state-changing RAS data containing information to a second station in the remote monitoring and control system; RAS information of the second station as a response to the state-changing RAS data from the second station And a response RAS data receiving means for receiving response RAS data including the following. 2. The RAS data transmitting means, if there is no response from the second station within a certain period after the transmission of the RAS data, transmits the RAS data again to the second station. The transmission device according to claim 1, wherein: 3. After a lapse of a certain period from the latest transmission of the state-changed RAS data, when the number of responses from the second station to the state-changed RAS data is smaller than the number of times of transmission of the state-changed RAS data, 2. The RAS data transmission means further comprising RAS data transmission number management means for causing the second station to transmit state change RAS data again.
Or the transmission device according to 2. 4. The status change RAS data and the response RA
4. The transmission apparatus according to claim 1, wherein the S data includes header information for distinguishing the changed RAS data from the response RAS data. 5. A method for transmitting RAS information between stations of a remote monitoring and control system, wherein the first station has its own RA
State change RAS including RAS information when S information changes
The second station that has transmitted the data to the second station,
Transmitting response RAS data including the RAS information of the second station to the first station as a response to the AS data, wherein the first station receives the response RAS data from the second station; The status change RAS sent by itself
Confirming that data has been communicated to said second station.