PLCcheck

S5 AWL Command: R (Reset)

S5 AWL instruction R (Reset): Resets a bit to FALSE when VKE is TRUE. Counterpart to S (Set).

·2 min read
S5AWLRResetRücksetzenbit logic

Diesen Artikel auf Deutsch lesen

S5 AWL Command: R (Reset)

The R instruction resets a boolean operand to FALSE when the VKE is TRUE. It is the counterpart to S (Set). R can also reset timers and counters.

Syntax

R  <operand>

S7 Equivalent

S5 AWLS7 STLS7 SCL
R A 4.0R Q 4.0 (EN) / R A 4.0 (DE)IF condition THEN output := FALSE; END_IF;

Code Example

U  E 0.1       // Stop button
R  A 4.0       // Reset motor output to FALSE

Also used for timers and counters:

U  E 0.3       // Reset condition
R  T 5         // Reset timer T5 to zero
R  Z 3         // Reset counter Z3 to zero

Related Commands

Part of the S5 AWL Command Reference. Maintained by PLCcheck.ai.

Analyze Your S5 Code Automatically

PLCcheck Pro reads your complete S5 AWL program and explains every instruction — including this one — in plain language. Upload your code and get instant documentation, S7 equivalents, and migration guidance.

Upload S5 code for free analysis → | S5→S7 Migration Guide →

Related Articles

plc-documentation

Reading and Understanding S5 AWL Code: A Practical Guide

Learn to read Siemens S5 AWL (Instruction List) code from scratch. Covers the accumulator model, bit logic, load/transfer, timers, counters, jumps, and data blocks with real code examples and line-by-line explanations.

16 min read

migration-guide

The Siemens S5/S7 Converter Tool: What It Does and What It Doesn't

Honest assessment of the Siemens STEP 7 S5→S7 conversion tool. What it converts automatically, what it cannot handle, common errors, and how to deal with the remaining 20–40% that requires manual work.

12 min read

migration-guide

S5 to S7 Migration: The Complete Guide (2026)

Step-by-step guide for migrating Siemens S5 PLC programs to S7-1500. Covers AWL→SCL conversion, timer mapping, address translation, and hardware selection.

18 min read

Analyze your PLC code with AI

PLCcheck Pro explains, documents, optimizes, and migrates PLC code — automatically.

Try PLCcheck Pro →
← Back to Blog

Not affiliated with Siemens AG. S5, S7, STEP 5, STEP 7, and TIA Portal are trademarks of Siemens AG.