This sample shows how to access files reading and/or writing from the CycleUpdate method, thus in a cyclic way.

This sample contains the following projects and module instances.

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A static library (TcAsyncFileIo) providing the file access.
Code for file access could be shared, thus this code is located in a static library used by the driver projects.

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One driver (TcAsyncBufferReadingDrv) providing two instances

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ReadingModule: Uses the static library to read the file AsyncTest.txt

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WriteDetectModule: Detecting write operations and initializing reads

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One driver (TcAsyncBufferWritingDrv) providing one instance

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WriteModule: Uses the static library to write the file AsyncTest.txt

When starting the sample, the writing module starts writing data to the file, which will be located in the Bootproject-Path (usually C:TwinCAT3.xBootAsyncTest.txt). The input variable “bDisableWriting” could be used in inhibit writing.

The objects are connected to each other: After writing is done the WritingModule triggers the DetectModule of the TcAsyncBufferReadingDrv. This initiates a read operation by the ReadingModule.

Please monitor the “nBytesWritten” / “nBytesRead” output variables of the WritingModule / ReadingModule. Additionally, log messages are generated on level “verbose”. As usual, these could be configured using the TraceLevelMax Parameter of the modules.

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One driver (TcAsyncFileFindDrv) providing one instance

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FileFindModule: Uses the static library to list files of a directory

Use the input variable “bExecute” to trigger the action. The Parameter “FilePath” holds the directory to list (default: “c:TwinCAT3.1Boot*”).

Please monitor the trace (Loglevel “Verbose”) for list of found files.