FB_Init to define length of array in FB

2021-02-02T01:03:25.815000Z

Thanks for clarifying. I did not realize they ran at different times.
I will look into the FB_Factory and see what I can do. Thank you.

FB_Init to define length of array in FB

2021-02-01T22:38:22.558000Z

FB_Init happens when you boot up the application.
ARRAY [0..ArrLen] OF INT; happens at compile time.
What you are looking at is allocating (and hopefully deallocating memory during runtime).
This is described in "B.)"here:
https://help.codesys.com/webapp/fb_factory;product=LibDevSummary;version=3.5.15.0

FB_Init to define length of array in FB

2021-02-01T21:02:19.716000Z

Hi,is there a method to pass a number through FB_Init and use it to define the length of the array which is internal to the FB?

Example

METHOD PUBLIC FB_Init : BOOL
VAR_INPUT
    bInitRetains : BOOL; // initializing of retain variable
    bInCopyCode : BOOL; // instance is copied to copy code
    ArrLength : INT; // additional input: number of the COM interface, that is to be observed
END_VAR

This^.ArrLen := ArrLength;

Where ArrLen is used in the FB as shown, to define array length?

FUNCTION_BLOCK FB_Example
VAR CONSTANT
    ArrLen : INT;
END_VAR

VAR
    Array1 : ARRAY [0..**ArrLen**] OF INT;
END_VAR

I understand Codesys forces you to use a constant to define the Array length and I cannot write to a constant. So I am hoping for a workaround. The idea is to make the FB use the correct amount of memory for the array on instantiation.

It would make sense that since the function block is instantiated with FB_Init I should be able to define the length of the array with the FB_Init.

Thanks.

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