How to choose a system integrator for an automation project: 12 questions to ask

To choose a system integrator, compare how they engineer and test, not just what they charge. The best predictor of a smooth start-up is a supplier who writes a clear specification, tests the software against a simulated machine before site, documents what they deliver and supports it afterwards. Relevant platform and industry experience matters, but process discipline separates good integrators from busy ones.

The questions below work for a single machine upgrade or a full line. Use them in a short interview with each shortlisted supplier, and ask for evidence rather than assurances.

12 questions to ask a system integrator

Experience and fit

1. Which similar projects have you delivered on our platform? Ask for the controller, software version and industry, and whether you can speak to the client.
2. Who exactly will do the engineering? Names and CVs of the lead engineer and programmer, not the sales team.
3. What will you subcontract? Panel building, site installation and specialist software are often subcontracted; that is fine if it is declared.

Engineering process

1. Who writes the functional specification, and when do we sign it? No code should start before the specification is agreed.
2. What coding standards do you follow? Ask to see a sample program; look for structure, comments and consistent naming.
3. How do you test before site? Look for simulation of the machine or process, written test cases and a proper factory acceptance test.

Quality, security and documentation

1. What quality system do you work to? ISO 9001 certification is a reasonable baseline.
2. How do you handle OT security and remote access? Expect familiarity with IEC 62443, especially requirements for service providers.
3. What documentation do we receive? As-built drawings, commented source code, I/O lists, test records and a backup procedure, all in editable formats.

Support and commercial terms

1. What happens after handover? Warranty period, response times, remote support route and cost.
2. Who owns the code? You should have unrestricted rights to modify and maintain it, without locked blocks.
3. How are changes priced and approved? A clear change process prevents disputes on site.

Signals of a mature integrator

Industry certification can help. The Control System Integrators Association runs a certification that audits integrators against best practices in ten areas, from project management and the system development life cycle to quality, service and cybersecurity. SCADA and PLC vendors also run partner programmes that require trained staff, such as the Inductive Automation integrator programme. Neither guarantees a good project, but both show investment in process.

Red flags

• A quote with no functional specification and no test plan
• Reluctance to name the engineers who will do the work
• No mention of how software is tested before arriving on site
• Locked or know-how-protected code blocks without a clear reason
• Vague support terms, or support only by calling one individual's mobile
• A price far below the others with no explanation of the difference

Comparing quotes fairly

Integrator quotes vary widely because scope is interpreted differently. Normalise them before comparing: list the deliverables you expect (specification, software, HMI, panels, installation, FAT, SAT, training, documentation, support) and ask each supplier to confirm which are included. Compare likely total cost, including your own staff time and production lost during start-up, not only the quoted price. A supplier who includes simulation testing and more FAT time may look dearer on paper and still cost less overall.

Run a short paid discovery first

For larger or unclear projects, consider paying your preferred integrator for a short discovery phase before awarding the full contract: a site visit, a review of drawings and existing code, and a draft functional specification. It costs a little up front and tells you a great deal about how they work. You see the quality of their documents, how they ask questions and whether their engineers understand your process. If it goes well, the specification becomes the basis of a fixed price. If it does not, you have a document any other integrator can quote against. Either way, the competitive quotes that follow will be based on the same, clearer scope, which makes them far easier to compare honestly.

Local, remote or both?

Local integrators are easy to visit and quick to reach site. Remote engineering partners can offer capacity and specialist skills that local markets lack, provided the work is tested in simulation and someone qualified is on site at start-up. Many plants now combine the two: a local partner for installation and site work, and a remote team for software and testing. Our guide to remote PLC programming covers how that split works in practice.

About Wartens

Wartens was founded in 2013, has delivered industrial projects since 2016 and has completed more than 100 automation projects, with ISO 9001:2015 certification across the group. We give you one contact in your country, engineering from our India centre, and remote acceptance before site work. Ask us the twelve questions: see automation engineering, read about Wartens or contact us.