Transmission apparatus, transmission system and data transmission method

Abstract

The invention provides a delivering device, a delivering system and a data delivering method. The delivering device (1) connects the system bus interface (11) as the interface of the computer (5) and the internal bus (16) of the communication interface (12) as the interface of the network, and the memory bus (17) for connecting the shared memory (14), which has: FCS generating potion (156), a final checking code FCS checking potion (153) of a data potion for calculating the additional frame while transmitting the frames, for normally checking the data according to the checking code of the data potion corresponding to the additional frame; and a receiving buffering potion (154), which remain the data of the receiving frame; the receiving buffering potion (154) can simultaneously processes the write-in and read-out and possesses the volume of the data which can at least retain the maximum frame length; only normal data is transmitted to the shared memory (14). So that the invention provides a method without the data updating period of a dispersed shared memory which can assure the data reliability of the delivering system and the shared memory.

Description

technical field [0001] The present invention relates to a transmission device, a transmission system, and a data transmission method, and in particular to a highly reliable transmission device suitable for transmitting data in a network system in which computers connected via a system bus (bus) are connected to each other via a network. Transmission system and data transmission method. Background technique [0002] In plant control, communication is known in which transmission devices connected to each other via a LAN (Local Area Network) periodically transmit the contents of a shared memory held by each transmission device to ensure data simultaneity. [0003] The transmission system that executes the above-mentioned communication is constructed by connecting respective computers connected via a system bus to each transmission device via a LAN. At this time, each delivery device constituting the delivery system has a built-in shared memory that allocates an area of ​​equal...

AI Technical Summary

Problems solved by technology

For this reason, shortening of the update cycle of data becomes difficult

[0012] In addition, in order to reduce the processing load of the MPU, when the communication I / F calculates the total value of data, if unnecessary data (garbage) occurs on the internal bus or inside the communication I / F during transmission, There is a possibility that the total value and FCS of the frame data are calculated by using the abnormal data, and the receiving side may mistakenly recognize it as normal

[0013] In this way, when the check of the total value of the frame data stored in the above-mentioned standard IP header is applied, the processing load of the MPU increases and the update cycle of the shared memory becomes longer.

In addition, when the communication I / F is provided with the check function of the total value of the frame data, useless data generated between the communication I / F cannot be detected by the memory.

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