PLC Software Engineering | Axiotech Technical Library - Axiotech Automation Ltd

TwinCAT 3 Structured Text Software Architecture: From Machine States to Reusable Function Blocks

axiomatrix — Sat, 29 Aug 2026 10:24:52 +0000

TwinCAT 3 supports IEC 61131-3 programming and integrates PLC, motion, I/O, HMI and PC-based software in one engineering environment. That flexibility is valuable, but a machine remains maintainable only when application logic is separated from hardware detail and every module has a clear responsibility. This guide describes the architecture Axiotech uses as a starting point for new machines…

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PLC State Machines, PackML, Interlocks and Fault Recovery in TwinCAT

axiomatrix — Sat, 29 Aug 2026 10:24:52 +0000

Many PLC problems are not caused by an incorrect output instruction. They arise because the machine has no single, testable definition of what it is doing, which commands are valid and how it recovers when a condition changes halfway through a sequence. An explicit state model turns that ambiguity into engineering information. PackML can provide a common vocabulary for machine states and modes…

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TwinCAT Version Control, Automated Builds, TcUnit and Release Evidence

axiomatrix — Sat, 29 Aug 2026 10:24:52 +0000

A PLC download can change the behaviour of a complete machine. The engineering lifecycle should therefore make it possible to answer four questions: what changed, who approved it, how it was tested and exactly what was deployed. TwinCAT projects can be managed with the same disciplined principles used in modern software development, provided generated artefacts, library dependencies…

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HMI, Alarm, Recipe and Diagnostic Design for Supportable Machines

axiomatrix — Sat, 29 Aug 2026 10:24:52 +0000

An HMI is part of the control-system interface, not decoration placed over PLC tags. It should explain current state, available actions and reasons why an action is unavailable. Good diagnostics reduce recovery time without giving the operator unsafe or ambiguous controls. Structure screens around running, changeover, setup, fault recovery, quality checks and maintenance rather than copying…

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ADS, OPC UA, MES and OEE: Designing a Reliable Machine-Data Architecture

axiomatrix — Sat, 29 Aug 2026 10:24:52 +0000

Making PLC symbols available on a network is not the same as creating production information. A reliable machine-data architecture defines semantics, quality, timestamps, ownership, security and behaviour when either side is unavailable. ADS, OPC UA, databases and MES interfaces have different strengths. The correct design uses each at an appropriate boundary while protecting deterministic…

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GAMP 5-Aligned Automation Software Documentation and Validation Support

axiomatrix — Sat, 29 Aug 2026 10:24:52 +0000

Regulated automation needs more than working PLC code. The customer must be able to understand what the system is intended to do, how risk has shaped the design, what was built, how it was tested, which version was released and how the validated state will be protected through change. Axiotech can supply TwinCAT, HMI, machine-data and industrial-software engineering with a documentation and…

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