# CODESYS NOT

Instructions · `NOT` · verification: source checked

NOT is an IEC bitwise operator that inverts each bit of its operand. An input bit of 0 produces an output bit of 1, and an input bit of 1 produces 0. It is written in Structured Text as, for example, Var1 := NOT 2#1001_0011; and can also be represented in FBD.

## Specification

| Property | Value |
|---|---|
| Language | iec 61131 3 |
| Code | NOT |
| Group | bitwise |
| Dialect | CODESYS |

## Study notes

- Permitted data types: BOOL, BYTE, WORD, DWORD, LWORD.
- The operator performs a bitwise NOT on a bit operand.
- Example: Var1 := NOT 2#1001_0011; gives the result in Var1: 2#0110_1100.
- The operator is shown in both ST and FBD representations.

## Sources

1. [Beckhoff Information System](https://infosys.beckhoff.com/content/1033/tc3_plc_intro/2528902283.html) (accessed 2026-10-26)
2. [CODESYS Group](https://content.helpme-codesys.com/en/CODESYS%20Development%20System/_cds_operator_not.html) (accessed 2026-10-26)

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JSON: https://machineschema.com/instruction/iec-not.json  
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