JP3972630B2 - Ethernet variable transmission system - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an Ethernet-like variable transmission method for detecting a change in data when transmitting data communication between control devices using a TCP / IP protocol on a transmission line using Ethernet, and transmitting the contents to the other party.
[0002]
[Prior art]
2. When data communication between control devices using the TCP / IP protocol is performed on a transmission line using the current technology Ethernet (registered trademark of Xerox bus structure LAN), as shown in FIG. There is state change data transmission in which state change data is generated by detecting a change and the contents are transmitted to the other party. The status change data transmission is a method of transmitting data to a partner apparatus by setting the address of the memory in which the data has changed, the bit position, and whether the bit is ON or OFF as a set.
[0003]
As shown in FIG. 4, the Ethernet driver 10 detects the change in data and creates the change data 11 by using the TCP / IP protocol on the transmission line using the conventional Ethernet. A transmission request a is made to (Ethernet I / F) 20. The Ethernet I / F 20 transmits b the status change data 11 to the partner apparatus 30 in accordance with the transmission request a. The counterpart device 30 receives the status change data 11 and acknowledges (ACK) c to the Ethernet I / F 20. The Ethernet I / F 20 receives this response c, notifies the Ethernet driver 10 of transmission completion d, and completes transmission. The state change data transmission is performed by creating state change data every time there is a state change.
[0004]
[Problems to be solved by the invention]
When state change data is transmitted by the state change data transmission method using the conventional TCP / IP protocol, there are the following problems.
(1) When transmission of state change data fails, the state change data that failed to be transmitted cannot be retransmitted. When the TCP protocol line is disconnected, the Ethernet I / F may fail to transmit the status change data. The serial line protocol has a function to retransmit data that failed to be transmitted when transmission fails, but the TCP protocol requires that the line be reconnected first even if the line is disconnected. There is a very high probability that retransmission in the protocol will fail.
(2) The state change cannot be detected when, for example, the state of the bit changes instantaneously from OFF → ON → 0FF until the transmission is completed after the state change data is transmitted. In the normal state change detection method, if state change data is not being transmitted, it is compared with the previous value whether there is a change in data in a steady cycle, and if change is detected, state change data is created and transmitted. When the transmission completion is notified from the Ethernet I / F, the status change data is set to the previous value, and status change data transmission is completed. In this method, state change detection is not performed in a steady cycle during state change data transmission, and therefore state change detection is not performed when a bit state change is instantaneously OFF → ON → OFF.
[0005]
The present invention has been made in view of the above-mentioned problems. Retransmission of status change data whose status change data failed to be transmitted, or status change frequently occurs between the transmission of this status change data and the completion of retransmission. In this case, it is an object of the present invention to provide an Ethernet-like change transmission system that detects change in the meantime, creates change data, and re-transmits the change data so that the change data can be transmitted in the order of creation.
[0006]
[Means for Solving the Problems]
The present invention requests an Ethernet interface for a first transmission request for transmitting state change data generated by an Ethernet driver detecting data change, and the Ethernet interface uses the TCP / IP protocol to send the state change data to the other party. In the Ethernet status change transmission method to be sent to the device, the Ethernet driver is provided with status change data storage means for saving status change data, the status change data transmission failed due to disconnection of TCP protocol line etc., and the Ethernet interface notifies the transmission failure when, the Ethernet driver has a retransmission function of the second transmission request again Ethernet interface state change data placed and stored in state change data storing means, to the Ethernet driver, the first transmission of the state change data detecting a state change from the time of transmission of the request every predetermined time It registers the state change creation processing unit and created forms the state change data creating state change data Te and state change data registration means is provided, said first transmission request Deformation transmitted at the second transmission request from the time of A third transmission request for requesting the Ethernet interface to transmit the state change data registered in the state change data registration means generated until the completion of data transmission after the second transmission request is transmitted ; Features.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1
FIG. 1 shows an operation explanatory diagram of an Ethernet-like variable transmission system having a retransmission function at the time of transmission failure according to the first embodiment. In the figure, 10 is an Ethernet driver for transmitting status change data, 20 is an Ethernet interface (Ethernet I / F), 30 is a counterpart device to which status change data is transmitted, and 11 is a status change created by detecting data changes. The data, 12 is the state change data storage means, 13 is the state change data taken out from the state change data storage means 12, and 14 is the state to release the state change data 13 stored in the state change data storage means 12 after transmission is completed. This is a variable data release means.
[0009]
This Ethernet variable transmission system will be described together with the operation. The Ethernet driver 10 stores the state change data 11 created by detecting the data change in the state change data storage unit 12 and sends a request a for the state change data 11 to the Ethernet I / F 20. The Ethernet I / F 20 transmits b the status change data 11 to the partner apparatus 30 in accordance with the transmission request a. If there is no acknowledgment (ACK) received from the counterpart device 30, the Ethernet I / F 20 resends the state change data 11 to b1 and b2. If there is no response from the partner device 30 even after two retransmissions, the Ethernet I / F 20 notifies the Ethernet driver 10 of the transmission failure e and notifies the partner device 30 that the connection is disconnected. When receiving the connection disconnection notification f, the partner apparatus 30 requests the Ethernet I / F 20 to reconnect. The Ethernet I / F 20 receives this connection reconnection request g, notifies the counterpart device 30 of reconnection permission, and completes the line reconnection of the Ethernet TCP protocol.
[0010]
When the Ethernet driver 10 is notified of the transmission failure from the Ethernet I / F, after the Ethernet TCP protocol line reconnection is completed, the status change data 13 (= 11) stored in the status change data storage means 12 is stored. The data is transmitted to the read Ethernet I / F 20 and a transmission request i for the state change data 13 is made. The Ethernet I / F 20 sends j the status change data 13 to the partner apparatus 30 in accordance with the retransmission request i. The counterpart device 30 receives the status change data 13 and acknowledges (ACK) k to the Ethernet I / F 20. The Ethernet I / F 20 receives this response k, notifies the Ethernet driver 10 of the completion of transmission, and completes transmission. The state change data 13 stored in the state change data storage unit 12 is released by the state change data release unit 14 upon completion of transmission.
[0011]
According to the first embodiment, the Ethernet I / F 20 may fail to transmit the state change data 11 when the TCP protocol line is disconnected. However, the Ethernet driver may change the state change data storage unit 12. By storing the state change data 11 in the case where a transmission failure is notified from the Ethernet I / F 20, it is possible to request transmission of the state change data stored and placed again. By using the retransmission function of the Ethernet driver 10, important data such as control data can be reliably transmitted to the counterpart device as state change data. Also, if the Ethernet cable is physically disconnected, the TCP protocol will not succeed even if the line is reconnected, but even in such a case, the TCP protocol can be replaced by replacing the cable with a normal one. As long as the line can be reconnected, it is possible to transmit the status change data that failed to be transmitted.
[0012]
Embodiment 2
FIG. 2 is an operation explanatory diagram of an Ethernet-like change transmission system having an instantaneous change detection guarantee function capable of detecting and transmitting an instantaneous change from the time of failure of transmission of change data to a retransmission according to the second embodiment. Indicates. In the figure, 10 is an Ethernet driver for transmitting status change data, 20 is an Ethernet I / F, 30 is a counterpart device, 11 is status data created by detecting data changes, and 12 is status data 11. State change data storage means, 13 is state change data extracted from the state change data storage means 12, and 14 is state change data release for releasing the state change data 13 of the state change data storage means 12 after transmission of the state change data 13. means. (The same as above in FIG. 1).
[0013]
15a to 15c are state change creation processing means for checking whether there is a state change by time-up T1 to T3 of first to third state change timers (not shown) and generating state change data in the case of state change. When the bit is turned ON → OFF or OFF → ON, it has a function of guaranteeing a change in state with a pulse in 500 msec. 16a to 16c are status change transmission buffer queues (status change data registration means) in which the status change data created by the status change creation processing means 15a to 15c are registered, and 17a and 17b are taken out from the status change transmission buffer queues 16a and 16b. The state change data 18a and 18b are state change data storage means for storing the state change data 17a and 17b, and 19a and 19b are the state change data storage means state changes 18a and 18b after the transmission of the state change data 17a and 17b is completed. This is state change data release means for releasing the data 17a and 17b.
[0014]
The operation of this Ethernet-like variable transmission system will be described. The Ethernet driver 10 stores the state change data 11 created by detecting the data change in the state change data storage unit 12 and makes a transmission request a of the state change data 11 to the Ethernet I / F 20. When the transmission request a for the state change data 11 is made, the first state change timer (not shown) is operated.
[0015]
In response to the transmission request a for the state change data 11, the Ethernet I / F 20 transmits b the state change data 11 to the partner apparatus 30. If there is no affirmative response (ACK) from the partner device 30, the Ethernet I / F 20 performs retransmission b1 and b2 of the status change data 11. If there is no response from the partner device 30 even after two retransmissions, the Ethernet I / F 20 notifies the Ethernet driver 10 of the transmission failure e and notifies the partner device 30 that the connection is disconnected. When receiving the connection disconnection notification f, the partner apparatus 30 requests the Ethernet I / F 20 to reconnect. The Ethernet I / F 20 receives this connection reconnection request g, notifies the counterpart device 30 of reconnection permission, and completes the line reconnection of the Ethernet TCP protocol.
[0016]
When the Ethernet driver 10 is notified of the transmission failure e from the Ethernet I / F 20 , after the Ethernet TCP protocol line reconnection is completed, the status change data 13 (= 11) stored in the status change data storage means 12 is stored. A transmission request i is made to the read Ethernet I / F 20. The Ethernet I / F 20 transmits j the status change data 11a to the counterpart device 30 in accordance with the transmission request i. The counterpart device 30 receives the status change data 13 and acknowledges (ACK) k to the Ethernet I / F 20. The Ethernet I / F 20 receives this response k, notifies the Ethernet driver 10 of the transmission completion, and the transmission of the state change data 13 (= 11) is completed. The state change data 13 stored in the state change data storage unit 12 when the transmission is completed is released by the state change data release unit 14.
[0017]
On the other hand, the first state change timer (not shown) that has started operation at the time of the transmission request a for the state change data 11 operates the state change creation processing means 15a at time-up T1. The state change creation processing means 15a detects a change in data, and if there is a state change, creates state change data and registers this state change data in the state change transmission buffer queue 16a. In addition, the second state change timer starts its operation by time-up T1 of the first state-change timer, and operates the state change creation processing means 15b by time-up T2. The state change creation processing means 15b detects a change in data, and if there is a state change, creates state change data and registers this state change data in the state change transmission buffer queue 16b. Similarly, the third status change timer starts operating when the second status change timer expires T2, and the status change creation processing means 15c is operated when the time expires T3. The state change creation processing means 15c detects a change in data, and if there is a state change, creates state change data and registers the state change data in the state change transmission buffer queue 16c . As described above, the state change processing means 15a to 15c detect the state change every predetermined time from the time when the state change data 11 is transmitted, and the state change data is generated when the state change is detected. The status change data is registered in the status change transmission buffer queues 16a to 16c, respectively.
[0018]
If transmission of the status change data 11 fails, the TCP protocol line is reconnected and transmission of the status change data 13 (= 11) is completed and then registered in the status change buffer queue 16a. The status change data 17a is stored in the status change data storage means 18a, and transmitted from the Ethernet driver 10 to the counterpart device 30 via the Ethernet I / F 20. When the counterpart device 30 responds (ACK) o and is notified of the transmission completion p, the status change data 17a stored in the Ethernet is released by the status change data release means 19a.
[0019]
When the transmission completion p is notified, the status change data 17b registered in the status change transmission buffer queue 16b is stored in the status change data storage means 18b, and the counterpart device is connected via the Ethernet I / F 20. 30 is transmitted q and r. When the counterpart device 30 responds (ACK) s and the transmission completion is notified from the Ethernet I / F 20, the status change data 17b stored in the status change data storage means 18b is released by the status change data release means 19b. . Similarly, when the transmission completion p is notified, the status change data 17b registered in the status change transmission buffer queue 16b is taken out and transmitted (not shown).
[0020]
According to the second embodiment, the time change timer for transmitting the state change data 11 is started and the state change creation processing means 15a to 15c confirms whether there is a state change every time the state change timer expires. The state change data 17a to 17b are created and registered in the state change transmission buffer queues 16a to 16c, and the state change data storage means 12 fails to transmit from the transmission a of the state change data 11. Can be transmitted after the completion of the transmission of the state change data 13 until the state change data 13 (= 11) is completely transmitted. For this reason, in the conventional TCP protocol, a considerable amount of time is spent until the line is reconnected after transmission of the state change data fails, and the loss of control data when the state change data cannot be detected during that time is eliminated. be able to. If the transmission of the state change data 17a (17b) fails, the state change data storage means 18a (18b) waits for the TCP protocol line reconnection in the same manner as when the state change data 11 fails to be transmitted. The stored state change data 17a (17b) can be transmitted.
[0021]
【The invention's effect】
(1) According to the present invention , when the TCP protocol line is disconnected, the Ethernet I / F sometimes fails to transmit the status change data, but the driver saves the status change data. Thus, when a transmission failure is notified from the Ethernet I / F, it is possible to request transmission again of the state change data stored and stored. By using the re-transmission function of this driver, it is possible to reliably transmit important data such as control data to the partner apparatus as state change data. Also, if the Ethernet cable is physically disconnected, the TCP protocol will not succeed even if the line is reconnected, but even in such a case, the TCP protocol can be replaced by replacing the cable with a normal one. As long as the line can be reconnected, it is possible to transmit the status change data that failed to be transmitted.
(2) Further, according to the present invention , in the TCP protocol, it takes a considerable time from failure of transmission of status change data to reconnection of the line, and status change data cannot be detected during that time. In this case, there is a risk that the control data is lost, but since it is possible to reliably detect the state change data during that time, transmission without risk of the control data being lost can be performed.
[Brief description of the drawings]
FIG. 1 is an operation explanatory diagram of an Ethernet-like variable transmission system according to a first embodiment of the present invention.
FIG. 2 is an operation explanatory diagram of an Ethernet-like variable transmission system according to Embodiment 2 of the present invention.
FIG. 3 is an explanatory diagram of a procedure for creating state change data.
FIG. 4 is an operation explanatory diagram of an Ethernet-like variable transmission system according to a conventional example.
[Explanation of symbols]
10: Ethernet drivers 11, 13, 17a to 17b ... State change data 12, 18a, 18b ... State change data storage means 14, 18a, 18b ... State change data release means 15a, 15b, 15c ... State change data creation processing means 16a , 16b, 16c ... state change transmission buffer queue (state change data registration means)
20 ... Ethernet I / F (Ethernet interface)
30 ... Counterpart device

Claims (1)

The Ethernet driver requests the Ethernet interface for a first transmission request to transmit the status change data generated by detecting the data change, and the Ethernet interface transmits the status change data to the partner apparatus using the TCP / IP protocol. In Ethernet variable transmission system,
The Ethernet driver is provided with status data storage means for saving status data, and when the status data transmission fails due to disconnection of the TCP protocol line and the Ethernet interface is notified of the transmission failure, the Ethernet driver saves the status data. A retransmission function for requesting the second transmission of the state change data stored in the means to the Ethernet interface again;
Ethernet driver Zhou registering a state change creation processing unit and created forms the state change data creating detect and state change data state change every predetermined time from the time the transmission of the state change data first transmission request provided and change data registration means,
The status change data registered in the status change data registration means generated between the time of the first transmission request and the completion of the status change data sent by the second transmission request is transmitted to the second transmission request. An Ethernet variable transmission system comprising a third transmission request for requesting transmission to the Ethernet interface after completion .

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