Make codes read reliably on a real line

Reading depends on the whole system

One good read does not prove line performance. These articles separate the image, the code quality, the reader settings and formal quality grading.

Guides in this direction

• Choosing machine vision lighting for DataMatrix codes marked on metal — Try low-angle dark field on recessed dot-peen marks, a diffuse dome on curved or mirror-like metal and coaxial light on a flat reflective face, add crossed polarizers where glare remains, and keep the setup that reads your worst parts across their poses. A clean decode is not a grade: where your application specification requires one, a verifier grades the mark to ISO/IEC 29158:2025 or to the edition the specification names.
• Replacing a fixed Cognex DataMan or KEYENCE SR reader: what has to match — Record what the installed reader delivers, from codes and field at the working distance to PLC data, timing, wiring, power and mounting, and check each item against one exact variant of the new reader. Our analog tool screens camera parameters only, so treat the models it shows as starting points and decide the swap with a paired test on your parts and PLC.
• Choosing an industrial code reader: fixed or handheld, label or direct part mark — Decide four things: what moves, label or direct mark, code type with module width, and the link to the controller. Then prove the exact variant with a read test on real codes.
• Why a code does not read, and what to check first — Save a failed frame and a good one, then change one thing per test. A smear suggests motion blur, while a sharp, well-framed image that fails points to the decoder.
• Working out the camera resolution a code needs — Divide the code's size, without its quiet zone, by its module count to get the module size. Size the camera from your decoder's pixels-per-module limits, then recheck them with the installed lens.

Related

• Solve a machine vision engineering task

How this material was prepared

Prepared by MVisionPro from the stated sources and the MVisionPro calculation engine. A physical test is claimed only when the material says so explicitly. Read the editorial method.

Editorial status: verified. Content updated 2026-09-23.