By Michael Barr
Note: This article offers practical guidance for attorneys engaging technical experts. It is general commentary, not legal advice. Consult counsel about any specific matter.
An industrial controls expert witness explains machines that move, and what was supposed to stop them. These matters carry a feature most technical litigation lacks: somebody was standing next to the equipment, so the safety analysis is rarely academic.
They know the safety architecture, not just the control logic
Guarding, interlocks, light curtains, emergency stops, two-hand controls, and safety-rated controllers exist as a layered system with its own standards and its own rated performance levels. Whether a hazard was adequately controlled is a question about that layer, and it is separate from whether the process logic was correct.
An expert who reads only the ladder logic will miss the architecture the case actually turns on.
They can read the logic that was actually deployed
Programmable logic controller programs live in ladder, structured text, and function block, and the deployed program frequently differs from the archived one. Online edits, forced I/O, and bypassed interlocks are common in production and are often the whole story.
The strong witness asks for the controller upload rather than the engineering file, and knows why those can differ.
They understand who integrated it
Industrial installations usually involve a machine builder, a systems integrator, and an end user who modified things afterward. Responsibility for a hazard is frequently distributed across all three, and the technical record of who changed what and when decides how it apportions.
An expert who analyzes the machine without the integration history answers a narrower question than the case asks.
They can reconstruct the event from process data
Historians, alarm logs, controller diagnostics, and drive fault records capture what the line was doing. Each has a sampling interval and a retention policy, and both matter. Reconstructing a sequence of seconds from data recorded at a coarser interval requires stated assumptions rather than confident narration.
They know that a robot is a system, not a machine
Modern cells combine motion control, vision, force sensing, and increasingly some learned behavior, coordinated across a network. A fault can originate in any of them and manifest somewhere else. Collaborative applications add a further layer, because the safety case depends on speed and separation logic rather than on a fence.
They separate misuse from foreseeable use
Operators defeat guards because production pressure rewards it. Whether that was foreseeable, and whether the design should have anticipated it, is a central question and one where experts often overreach in both directions. The credible witness addresses it directly rather than treating any deviation as user error.
They can show the machine to a jury
These cases are demonstrable. Video, animation, and physical exemplars carry the explanation in a way testimony alone does not, and an expert who thinks about exhibits early produces better evidence than one who writes first.
Expert profiles in this field
Anonymized profiles. Names follow a conflicts check.
- Industrial PLC and SCADA systems
- Embedded software design
- Power electronics and motor drive
- Manufacturing automated test
- Electronic vehicle controls
- Secure embedded systems
How we help
We staff these matters across the boundary between controls, mechanical design, and safety process, because that is where responsibility usually sits. Our machine controls and robotics expert witnesses work alongside our materials and mechanical experts where a physical failure has a control system behind it, and our failure analysis practice covers the combined investigation.
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