# CODESYS LT

Instructions · `LT` · verification: source checked

LT is an IEC comparison operator that performs the "less than" function. If the first operand is less than the second operand, the operator yields TRUE; otherwise it yields FALSE. The operands may be of any basic data type.

## Specification

| Property | Value |
|---|---|
| Language | iec 61131 3 |
| Code | LT |
| Dialect | CODESYS |

## Study notes

- Permitted data types of the operands: any basic data type.
- The operator result is boolean: TRUE when the first operand is less than the second, otherwise FALSE.
- Source example in ST: Var1 := 20 < 30; where 20 < 30 yields TRUE.

## Sources

1. [Beckhoff Information System](https://infosys.beckhoff.com/content/1033/tc3_plc_intro/2528988299.html) (accessed 2026-10-26)
2. [CODESYS Group](https://content.helpme-codesys.com/en/CODESYS%20Development%20System/_cds_operator_lt.html) (accessed 2026-10-26)

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