Home

Beckhoff documentation

Published from _docs/README.md — edit it there, not here. Changes made in the wiki are overwritten on the next sync.

The TwinCAT 3 side of DT_PSA_OPCV — installing it, running the machine against it, and how the PLC projects are organised.

Read the main documentation first. It covers the machine, the Unity twin, and everything that is not specific to a control platform. This set assumes you have the twin open already.

Page	Answers
01 · Setup	What the PC needs, installing TwinCAT, isolated cores, the two network adapters and the loop cable, the PLC libraries, building and connecting to the twin
02 · Usage	Running the machine: startup order, the operator panel, the web HMI
03 · Architecture	How PLC_1 and SIM_1 are organised, and why there are two

Where the TwinCAT realisation is described

Not here. Like the machine description in the main repository, the per-group TwinCAT detail is generated from the PLC projects, so it cannot drift:

Looking for	Read
What TwinCAT makes of the machine, group by group	_docs/context/machine.md
A group's verified control PLC paths and terminal mapping	_docs/context/fg-*.md
Which terminal channel every signal is on	_docs/context/plc-io.md
How the SPT framework is meant to be used	_docs/reference/spt-framework.md
Which signals are unlinked on purpose	_docs/reference/plc-io-exceptions.md

Read _docs/context/PROVENANCE.md first — it says how current the type model is and which build of the twin export it was matched against.

Behaviour is not documented here either

Sequences, the station handshake, interlocks, fault codes and the reset model are machine-level contracts and live in the main repository, at _docs/reference/. They were written from this module's ST — because that is where the behaviour was first made to work — but any control platform running this line has to honour the same ones.

This module documents its realisation of those contracts, never a second version of them.

Paths are main-repository-root relative

Every path in every generated document here is spelled from the main repository root, not from Beckhoff/ — so Beckhoff/TwinCAT_1/PLC/PLC_1 rather than TwinCAT_1/PLC/PLC_1. That is the level this project is written from, and it stays true when the module is read inside a main-repo checkout.