Attention

These docs are a bit ambitious. The steps described are accurate but IronPLC cannot yet run programs.

P4015

Code

P4015

Message

User-defined type has the same name as a standard library type

This error occurs when a user-defined type has the same name as a standard library type.

IEC 61131-3 defines standard library function blocks (such as TON, TOF, TP, CTU, CTD, CTUD, R_TRIG, F_TRIG, RS, SR) that are built into the language. User-defined types cannot use these reserved names.

Example

The following code will generate error P4015:

FUNCTION_BLOCK TON  (* Error: TON is a standard library type *)
VAR_INPUT
    value : INT;
END_VAR
END_FUNCTION_BLOCK

The name TON is reserved for the standard library On-Delay Timer function block.

To fix this error, use a different name for your function block:

FUNCTION_BLOCK MyTimer  (* Correct: Custom name *)
VAR_INPUT
    value : INT;
END_VAR
END_FUNCTION_BLOCK

Standard Library Function Blocks

The following names are reserved for standard library function blocks:

• Bistable: SR, RS

• Edge Detection: R_TRIG, F_TRIG

• Counters: CTU, CTD, CTUD

• Timers: TON, TOF, TP