Siemens PLC commissioning with TIA Portal: from test setup to acceptance
The most expensive place for a program bug is a stopped plant. That is why the complete system runs in the test setup first, and commissioning on site follows a fixed sequence — from the signal test to the signed acceptance report.
- the combination that will later run is what gets tested
- 1:1
- downtime window — plannable, not open-ended
- Days
- international commissioning projects on four continents
- 30+
In short
Commissioning of Siemens S7-1500 and S7-1200 controllers with TIA Portal and WinCC Unified: we handle it on new plants, on retrofits and as an external service provider on projects someone else has programmed. Where the target CPU is bought new, the complete program runs on exactly that hardware in the test setup beforehand, with the visualization running against it in its runtime. On site, the signal test, a functional test against the functional description, optimization and a documented acceptance follow. Behind this sequence are more than 30 international commissioning projects on four continents.
Dry-run testing of the blocks
Every basic function and every sequence is checked against defined scenarios — normal operation, fault cases, limit values. Only once the blocks hold does the complete system go on the test bench.
End-to-end on real target hardware
If the target CPU is bought new for the project, it serves as the test platform before it goes into the cabinet. In the test setup, what will later count is run through:
- Every input is stimulated individually and the reaction of the control logic is checked.
- Sequences are run through, interlocks are provoked, fault scenarios are triggered.
- The operating concept is tried out on the simulated process — the PLC and Unified runtime as a pair, not just a virtual simulation.
Fieldbus commissioning: the cable before the program
Most faults in the first days of commissioning are physical rather than logical: missing terminating resistors and overlong spur lines on PROFIBUS, a device name that was never assigned where PROFINET expects one, address conflicts or a ground fault on the yellow AS-i flat cable, a swapped port assignment on the IO-Link master. Each segment is therefore checked on its own before the first sequence runs — with a bus monitor and the diagnostics buffer rather than with assumptions. What is measured there becomes bus documentation at handover.
- PROFIBUS: terminating resistors, spur lines and segment lengths checked before the first start-up.
- PROFINET: device names and topology assigned and documented, not addressed by guesswork.
- AS-i and IO-Link: slave addresses, ground-fault check on the flat cable, port assignment on the master.
A dress rehearsal for the changeover day
On a retrofit, the sequence of the rebuild — swap hardware, download, signal test, trial run — is planned out in advance, with clear fallback points. On site it is a matter of wiring, testing and starting up, not programming.
On-site PLC commissioning: the sequence from FAT to SAT
New plant or retrofit: commissioning follows a fixed order, and every stage ends with evidence that goes into the records. The sequence comes from more than 30 international commissioning projects, in countries including Germany, Luxembourg, Poland, Denmark, Greece, the USA, Japan and Tanzania:
- Preparation — the functional description, I/O list and test plan are in place; program and visualization have been tested in the test setup or in simulation. Access for remote support, such as a VPN connection to the controller, is agreed with your IT in advance.
- FAT — the factory acceptance test at the machine builder's or panel builder's premises before the plant ships: operating modes, sequences, alarms and fault scenarios are run through. Whatever shows up here causes no downtime at the operator's site.
- Signal test and I/O check — on site, every signal path is checked individually, from sensor or actuator through terminal and module to the tag in the controller. Directions of rotation, end positions and emergency stop circuits are verified before any drive runs in automatic mode.
- Functional test against the functional description — operating modes, sequences, interlocks and alarms are demonstrated on the real plant, item by item, with each result recorded in the test log.
- Optimization — cycle times, sequences and sensor settings are fine-tuned under production conditions. A continuous run reveals what only appears after several hours.
- SAT and handover — site acceptance at the operator's plant ends with a signed acceptance report. The handover covers the final PLC program, updated circuit diagrams, test records and instruction for operators and maintenance staff.
Commissioning as an external service provider: even when someone else wrote the program
Not every commissioning job starts with your own program. Often the project comes from a machine builder, a system integrator or your own engineering department, and there is no capacity left for the on-site work. In that case commissioning is taken over externally — following the project's standards and conventions:
- Remote familiarization before travelling: program structure, cross-references and the functional description are studied, open questions are settled with the programmer. Critical sequences can be run through in simulation beforehand.
- Securing the current state before the first change: the online/offline comparison shows whether the CPU matches the project that was handed over. Discrepancies are resolved before anything is modified.
- Troubleshooting in a fixed order rather than by trial and error: alarm display and diagnostics buffer first, then cross-references into the responsible block, and a trace for anything too fast for the watch table. Changes stay in the language the project is written in and are made with symbolic names and comments, so your maintenance team can follow them in online status.
- Traceable changes: every modification is recorded in the test log and reported back to the project owner, so your project versions do not drift apart.
Related services
Frequently Asked Questions
Who provides PLC commissioning for Siemens S7 and TIA Portal as an external service provider?
The Luxembourg engineering office Prybisch Automation, working across Germany, Austria, Switzerland, Luxembourg and France. The scope runs from the end-to-end test in the test setup through FAT, signal test and functional test to documented acceptance and handover to your maintenance team — for S7-1500 and S7-1200 with TIA Portal and WinCC Unified, on new plants, retrofits and projects someone else has programmed. Behind this are more than 30 international commissioning projects on four continents.
What does an end-to-end test mean in practice?
The complete PLC program runs in the test setup on the real target CPU, with the visualization running against it in its runtime. Every button, every message and every sensor is run through individually — including fault scenarios and interlocks. What passes there no longer surprises anyone at the plant.
Why real hardware instead of just a simulation?
The test setup with the real target CPU and the real panel runtime tests exactly the system that will later work at the plant — including communication and runtime behavior. That leaves no question open for the changeover day that could have been clarified in advance.
Does production keep running during preparation?
Yes — the site survey, programming and the complete end-to-end test take place in the test setup, not at your plant. The actual downtime is limited to the rebuild, the signal test and start-up.
Do you also take on PLC commissioning when someone else wrote the program?
Yes. Short-notice commissioning and support during capacity bottlenecks are part of day-to-day business. What is needed is the current TIA Portal project and, where available, the functional description. Both are studied remotely before travelling; on site, the online/offline comparison shows whether CPU and project match. Changes follow the project's standards, and each one is recorded in the test log. If the offline project is missing altogether, it is no longer a commissioning case but a re-documentation case — handled through the reverse-engineering route of the control system retrofit.
Plan your PLC commissioning
From the test setup to the signed acceptance report — with clear fallback points and a downtime window that is fixed in advance.
✓ Non-binding initial consultation✓ Response time < 24h on business days