Welcome to our new forum
All users of the legacy CODESYS Forums, please create a new account at account.codesys.com. But make sure to use the same E-Mail address as in the old Forum. Then your posts will be matched. Close

Number Changing Detector Function Block

Codesys V2.3 🇬🇧
sugur
2022-08-31
2022-08-31

  • sugur - 2022-08-31

    I need a function block which detects any changing of the input (of INT, WORD). I believe that there is already such a function block in the present libraries.

     

  • sgronchi - 2022-08-31

    Perhaps you can find it in OSCAT, not in the standard libraries.
    Anyway...

    FUNCTION_BLOCK InputChangeMonitor_WORD
VAR_INPUT
    i_Value : WORD;
END_VAR
VAR_OUTPUT
    o_Changed : BOOL;
END_VAR
VAR
    old_Value : WORD;
END_VAR

o_Changed := i_Value <> old_Value;
old_Value := i_Value;

    And with threshold

    FUNCTION_BLOCK InputChangeMonitorThresholded_WORD
VAR_INPUT
    i_Value : WORD;
    i_Threshold : WORD;
END_VAR
VAR_OUTPUT
    o_Changed : BOOL;
END_VAR
VAR
    old_Value : WORD;
END_VAR

IF i_Value > old_Value THEN
    o_Changed := i_Value - old_Value > i_Threshold;
ELSE
    o_Changed := old_Value - i_Value > i_Threshold;
END_IF

IF o_Changed THEN
    old_Value := i_Value;
END_IF

    Just change WORD to INT everywhere if you need to.

     

    Last edit: sgronchi 2022-08-31

  • sugur - 2022-08-31

    Wow! That was easy. Thank you.

     

Log in to post a comment.