PLC Memory Optimization: Reducing Data Block Usage
Practical techniques for reducing PLC memory usage on S7-300/400 where memory is limited. Covers DB optimization, marker cleanup, dead code removal, and string handling.
PLCmemoryoptimization
Blog
Guides, tutorials, and insights for PLC professionals.
Code & Programming(7)
8 min read
Refactoring Legacy PLC Code: From Spaghetti to Structure
How to refactor messy legacy PLC code into maintainable structure. Covers identifying spaghetti code, step-by-step refactoring, when to refactor vs. rewrite, and practical examples.
PLCrefactoringlegacy code
Common PLC Programming Mistakes and How to Fix Them
The 10 most common PLC programming mistakes found in industrial plants. Each mistake with explanation, real-world consequence, and fix. Covers S5 and S7.
PLCprogrammingmistakes
Optimizing PLC Scan Time: Practical Techniques
Practical techniques for reducing PLC cycle time. Covers code structure, conditional execution, data type selection, optimized data blocks, and interrupt-based architecture.
PLCscan timecycle time
PLC Code Review Best Practices for Industrial Plants
How to conduct a systematic PLC code review in an industrial plant. Covers what to check, how to prioritize, common issues found, and a review checklist.
PLCcode reviewbest practices
How to Create a PLC Variable/Tag Table from Scratch
Step-by-step guide for creating a PLC symbol table or tag table when no documentation exists. Covers I/O assignment, naming conventions, and tools for STEP 7 and TIA Portal.
PLCvariable tabletag table
Understanding Legacy PLC Code: Pattern Recognition Guide
How to read and understand undocumented legacy PLC code by recognizing common patterns: self-holding circuits, step sequences, safety interlocks, analog scaling, and communication blocks.
PLClegacy codepattern recognition
Migration Guides(25)
Mitsubishi A-Series to iQ-R Migration Guide
Overview of migrating Mitsubishi MELSEC A-series PLCs to the iQ-R platform. Covers software conversion (GX Works2/3), hardware changes, network migration (MELSECNET to CC-Link IE), and common pitfalls.
MitsubishiA-seriesiQ-R
Schneider Modicon to M580: Migration Overview
Overview of migrating Schneider Electric Modicon Quantum and Premium PLCs to the M580 ePAC. Covers the Unity M580 Application Converter (UMAC), hardware mapping, and EcoFit modernization services.
Schneider ElectricModiconQuantum
Cross-Platform PLC Migration: Siemens to Allen-Bradley
What to expect when migrating between Siemens S7 and Allen-Bradley ControlLogix. No automatic conversion exists — this guide covers the manual approach, key differences, and planning.
cross-platformSiemensAllen-Bradley
Converting Ladder Logic to Structured Text: Why and How
When and how to convert PLC ladder logic (LD/KOP/LAD) to Structured Text (ST/SCL). Covers the benefits, conversion patterns, what to keep in ladder, and practical examples.
Ladder LogicStructured Textconversion
IEC 61131-3 Compliance: Making Your PLC Code Portable
How to write PLC code that is portable between different manufacturers. Covers IEC 61131-3 compliance levels, vendor-specific extensions to avoid, and practical portability strategies.
IEC 61131-3portabilitycross-platform
RSLogix 500 to Studio 5000: Program Conversion Guide
Detailed guide to the software conversion process from RSLogix 500 to Studio 5000 Logix Designer. Covers the Logix Designer Export tool, Project Migrator, file preparation, and post-conversion cleanup.
RSLogix 500Studio 5000conversion
Allen-Bradley DH+ to EtherNet/IP: Network Migration Guide
How to migrate an Allen-Bradley Data Highway Plus (DH+) network to EtherNet/IP. Covers bridge solutions (1756-DHRIO, AN-X2-AB-DHRIO), full migration, MSG instruction conversion, and phased approach.
Allen-BradleyDH+Data Highway Plus
PLC-5 vs. ControlLogix: Key Instruction Set Differences
The most important instruction set differences between PLC-5 and ControlLogix that affect migration. Block Transfers, indirect addressing, PID, ASCII handling, and data types.
Allen-BradleyPLC-5ControlLogix
PLC-5 to ControlLogix Migration: Complete Guide
Complete guide for migrating Allen-Bradley PLC-5 programs to ControlLogix. Covers software conversion, hardware replacement, network migration (DH+ to EtherNet/IP), I/O mapping, and common pitfalls.
Allen-BradleyPLC-5ControlLogix
SLC 500 to CompactLogix: Step-by-Step Conversion
Step-by-step guide for converting Allen-Bradley SLC 500 programs to CompactLogix using Studio 5000. Covers the Logix Designer Export, tag cleanup, I/O remapping, and post-conversion testing.
Allen-BradleySLC 500CompactLogix
Optimized vs. Standard Data Blocks in S7-1500: What Every Migrator Must Know
Complete guide to optimized vs. standard (non-optimized) data blocks in S7-1500 and S7-1200. Architecture, performance, migration impact, PUT/GET compatibility, OPC UA, and when to use which.
S7-1500data blocksoptimized
STEP 7 Classic to TIA Portal: What Changes for the Programmer
A practical guide for experienced STEP 7 Classic programmers moving to TIA Portal. Covers the 15 most important differences in daily workflow: editor, tags, DBs, compilation, online access, debugging, and gotchas.
STEP 7TIA PortalSIMATIC Manager
Handling S5 Special Function Blocks (OB, SB) in S7
How to migrate S5 organization blocks (OB) and step blocks (SB) to S7. Covers OB number mapping, startup OBs, interrupt OBs, and SB conversion strategies.
S5S7OB
S5 Absolute Addressing vs. S7 Symbolic Addressing
Why S5 uses absolute addresses (E 0.0, MW 10, DB10.DW5) and S7 prefers symbolic names (Start_Button, Temperature, Motor.Speed). Migration strategy for converting absolute to symbolic.
S5S7addressing
Migrating S5 Counter Programs (Z/ZV/ZR) to S7
How to migrate S5 counter programs to S7. Covers ZV (count up), ZR (count down), BCD format differences, S7 equivalents (S_CU, S_CD, CTU, CTD, CTUD), and common pitfalls.
S5S7counter
Understanding S5 Data Blocks (DB0, DB1, DX0) in S7
What are S5 system data blocks DB0, DB1, and DX0? Why they exist, what they contain, and how to handle them during S5 to S7 migration.
S5S7data block
S5 Function Blocks to S7: FB/FX Migration Guide
How to migrate S5 function blocks (FB, FX) to S7. Covers parameter passing differences, formal operands vs. block interface, instance data blocks, and standard FBs (FB250, FB251).
S5S7function block
S7-300 End-of-Life 2033: Migration Timeline & Planning
Practical migration timeline for S7-300 plant operators. Year-by-year plan from 2025 to 2035, covering spare parts availability, price escalation, and prioritization of critical systems.
SiemensS7-300S7-1500
S7-300 to S7-1500 Migration: Complete Guide
Step-by-step guide for migrating Siemens S7-300 PLC programs to S7-1500 using TIA Portal. Covers hardware mapping, software migration wizard, optimized data blocks, AWL→SCL conversion, and common pitfalls.
SiemensS7-300S7-1500
STL/AWL Deprecation in S7-1500: Why You Must Convert to SCL
Why AWL/STL runs only in emulation mode on S7-1500, what that means for performance and maintainability, and how to convert your STL code to SCL. Includes conversion strategy and code examples.
AWLSTLSCL
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.
S5S7converter
S5 to S7 Address Mapping: Complete I/O Conversion Table
Complete reference for converting Siemens S5 PLC addresses to S7 format. Covers inputs (E→I), outputs (A→Q), flags (M/F), data blocks (DW→DBW×2 with bit-level mapping), timers, counters, and peripherals.
S5S7address
S5 Timer Conversion: KT Values to IEC Timers
Complete guide to converting Siemens S5 KT timer values to S7 IEC timers (TON, TOF, TP). Includes BCD format explanation, conversion table with 20+ examples, and behavior differences between S5 and IEC timers.
S5S7timer
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.
S5S7migration
Converting S5 AWL to S7 SCL: Step-by-Step
Practical guide for converting Siemens S5 AWL (Instruction List) code to S7 SCL (Structured Text). Includes conversion tables, code examples for bit logic, timers, counters, jumps, and data blocks.
AWLSCLSTL
Industry Insights(16)
Machine Directive & CE Marking After PLC Migration
Does replacing a PLC require a new CE assessment? When a PLC migration triggers the "substantial modification" clause, what the new EU Machinery Regulation 2023/1230 changes, and how to stay compliant.
CE markingmachine directivemachinery regulation
AI in Industrial Automation: Beyond the Hype
An honest assessment of where AI actually delivers value in industrial automation today, where it is still hype, and what plant operators should focus on. Predictive maintenance, code analysis, quality inspection, and the role of PLCs in an AI-driven future.
AIartificial intelligenceindustrial automation
Why Your PLC Code Is Your Most Undervalued Asset
Your PLC code contains decades of process knowledge worth millions — yet it appears nowhere on the balance sheet. Why industrial automation code deserves to be treated as a strategic business asset, and what happens when it is not.
PLCcodeasset
PLC Obsolescence: The Spare Parts Crisis in Industrial Automation
The PLC spare parts crisis explained: Siemens S5 (EOL 2020), S7-300 (production stopped Oct 2025), and what plant operators must do now. Lifecycle timelines, pricing trends, and mitigation strategies.
PLCobsolescencespare parts
5 Signs Your PLC System Needs an Urgent Upgrade
Five concrete warning signs that your PLC system has become a liability. Each sign with real-world consequences and what to do about it. For plant managers and operations leaders.
PLCupgradesigns
PLC Migration ROI: How to Build the Business Case
How to calculate PLC migration ROI and build a convincing business case. Covers cost savings, risk reduction, productivity gains, and a ready-to-use calculation framework.
PLCmigrationROI
Big Bang vs. Gradual Migration: Which Strategy Fits Your Plant?
Comparison of two PLC migration strategies: complete system replacement in one shutdown vs. gradual machine-by-machine migration. Decision criteria, risks, costs, and hybrid approaches.
PLCmigrationstrategy
TIA Portal vs. STEP 7 Classic: Key Differences for Migrators
Side-by-side comparison of Siemens TIA Portal and STEP 7 Classic (SIMATIC Manager). Interface, programming, hardware support, licensing, and migration path.
TIA PortalSTEP 7SIMATIC Manager
Legacy PLC Emulators vs. Full Migration: Pros and Cons
Comparison of PLC emulator/adapter solutions vs. full program migration. When emulation makes sense as a bridge, and why it is not a long-term solution.
PLCemulatoradapter
Siemens S5 End-of-Life: Complete Timeline & Implications
Complete timeline of the Siemens SIMATIC S5 PLC from introduction in 1979 to end-of-life on 30.09.2020. What the EOL means for spare parts, repairs, software, and your migration planning.
SiemensS5end-of-life
The Hidden Cost of Knowledge Loss: When Your PLC Expert Retires
What happens when the only person who understands your PLC programs leaves? Concrete scenarios, real cost calculations, and practical strategies to capture critical automation knowledge before it walks out the door.
PLCknowledge lossretirement
Make or Buy: PLC Migration In-House vs. Service Provider
Decision guide for plant operators: Should you migrate your PLC system in-house or hire an external integrator? Compares cost, risk, timeline, and quality for both approaches with a practical decision matrix.
PLCmigrationmake or buy
Undocumented PLC Code as a Safety Risk
How undocumented PLC programs create operational, safety, and compliance risks. Covers knowledge loss, uncontrolled changes, cybersecurity exposure, and what IEC 62443 and the EU Machinery Regulation require.
PLCsafetyrisk
S7-300/400 End-of-Life: What Plant Operators Need to Plan Now
Complete timeline for the Siemens S7-300 and S7-400 product phase-out. Key dates, spare parts availability, price implications, and a practical migration planning guide for plant operators.
S7-300S7-400end of life
The True Cost of PLC Migration: A Realistic Calculation
Realistic cost breakdown for migrating a Siemens S5 PLC to S7-1500. Covers hardware, software licenses, engineering hours, commissioning, and hidden costs with concrete price ranges for small, medium, and large systems.
PLCmigrationcost
Why S5 Migration Can't Wait Until 2027
The business case for migrating Siemens S5 PLCs now, not later. Covers the spare parts crisis, knowledge drain, compliance risks, and why every year of delay increases migration cost exponentially.
S5migrationend of life
Documentation(3)
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.
S5AWLSTL
Taking Over an Undocumented PLC System: A Survival Guide
Practical step-by-step guide for technicians taking over an unknown PLC system. Covers the first-week checklist: hardware audit, program backup, risk assessment, spare parts, and building system knowledge from scratch.
PLCundocumentedmaintenance
How to Document a PLC Program Without Original Documentation
Practical step-by-step method for documenting an undocumented PLC program. Covers block inventory, I/O tracing, cross-reference analysis, symbol table creation, and generating useful documentation from raw code.
PLCdocumentationundocumented