FB_CodeActivation — CoDeSys ST

Universal Function Block for toggling outputs via numeric code input on HMI (e.g. EasyBuilder / Weintek).
Use it to activate options, modes, access levels, or any feature that requires a numeric unlock code.

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How it works

The operator enters a numeric code on the HMI screen and presses Confirm.

• If the code matches one of the configured codes → the corresponding output toggles ON/OFF and a success notification appears for 3 seconds.
• If the code does not match any entry → an error notification appears for 3 seconds.
• Entering the correct code a second time disables the output (toggle behavior).

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Interface

VAR_INPUT

Variable	Type	Description
xConfirm	BOOL	Rising edge triggers code check (HMI confirm button)

VAR_IN_OUT

Variable	Type	Description
rInputCode	REAL	Entered code — automatically reset to 0 after a match

VAR_OUTPUT

Variable	Type	Description
xOutput1	BOOL	Output 1 active
xOutput2	BOOL	Output 2 active
xOutput3	BOOL	Output 3 active
xOutput4	BOOL	Output 4 active
xCodeOk	BOOL	Notification: correct code entered (high for 3 s)
xCodeError	BOOL	Notification: wrong code entered (high for 3 s)

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Configuration

Activation codes are defined inside the FB as VAR:

rCode1 : REAL := 2134;   // Output 1
rCode2 : REAL := 3421;   // Output 2
rCode3 : REAL := 2314;   // Output 3
rCode4 : REAL := 2341;   // Output 4

Change these values to your own codes before building.

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Usage example

// Global / HMI variables
VAR_GLOBAL
    gConfirm    : BOOL;
    gInputCode  : REAL;
    gOut1       : BOOL;
    gOut2       : BOOL;
    gOut3       : BOOL;
    gOut4       : BOOL;
    gCodeOk     : BOOL;
    gCodeError  : BOOL;
END_VAR

// PLC_PRG
VAR
    fbCode : FB_CodeActivation;
END_VAR

fbCode(
    xConfirm   := gConfirm,
    rInputCode := gInputCode,
    xOutput1   => gOut1,
    xOutput2   => gOut2,
    xOutput3   => gOut3,
    xOutput4   => gOut4,
    xCodeOk    => gCodeOk,
    xCodeError => gCodeError
);

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Toggle logic

Code entries	State
0 times	Output OFF
1 time	Output ON
2 times	Output OFF (reset)

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Requirements

• CoDeSys V3 (tested on V3.5)
• Standard library: Standard.library (R_TRIG, TON)
• HMI: any panel that can write a REAL variable and a BOOL trigger (EasyBuilder / Weintek recommended)

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Author

Nikita Poliakov — Automation & Instrumentation Engineer
2+ years delivering end-to-end control systems for food and meat-processing equipment.
LinkedIn | work.nikita@bk.ru

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License

MIT