Cache data

2020-12-22T11:06:49.697000Z

VAR_GLOBAL PERSISTENT RETAIN
    aAuthData : ARRAY[0..300] OF AuthData;
    udiInsertIndex : UDINT := 300;
    udiReadIndex : UDINT := 300;
    processed : BOOL := TRUE;
END_VAR

//Adding a value:
IF xNewData THEN
    udiInsertIndex := (udiInsertIndex+1) MOD 301;
    aAuthData[udiInsertIndex] := newAuthData;
    xNewData := FALSE;
END_IF

//Checking for new values:
IF udiReadIndex <> udiInsertIndex AND processed THEN
    udiReadIndex := (udiReadIndex+1) MOD 301;
    processed := FALSE;
END_IF

//Process the new value
IF NOT processed THEN
    //Process the value and set processed when finished
    DoSomethingWith(aAuthData[udiReadIndex], processed);
END_IF

Cache data

2020-12-22T10:36:54.617000Z

{attribute 'qualified_only'}
VAR_GLOBAL PERSISTENT RETAIN
    aAuthData : ARRAY[0..300] OF AuthData;
END_VAR

How could I set-up a circular array?
Would you mind showing some resources, examples? :)

Thanks for your help in advance.

Cache data

2020-12-22T10:33:20.741000Z

If the requirement is really not to lose any then the file-based persistence manager may be too slow for you.
Use a controller with non-volatile ram setup for retain data. Then use a circular array stored in VAR PERSISTENT. The array size should be as big as the maximum number of userids you intend to buffer.

Cache data

2020-12-17T20:23:01.405000Z

Hello,

What would be an ideal solution to save data before processing them.

I mean I am reading strUserID and I want to persist them before saving them to a MySQL database.

Actually I would like to use 2 tasks. One collecting strUserID while another one handling MySQL connection and sending of them.

The problem that I would like to save the strUserID before sending them thus in case of power outage, I didn't lose any strUserID.

I don't know whether to use collections (persisted) or persistent manager (as txt) or var persistent?

Thanks for your help in advance.

BR!

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