SICK Lector — NO READ Recovery (Focus & Code Type)

SICK · beginner · 20 min

A SICK Lector code reader outputting NO READ usually has the wrong focus for the working distance or the code type disabled — not a failed camera. Set focus for the exact distance and enable the symbology in SOPAS.

ℹ️ The Lector's focus is set for one working distance and does not auto-track. If the part moved closer or farther, or the code type isn't enabled, you get NO READ even though the reader is healthy.

What NO READ means

A SICK Lector image-based code reader activates its NO READ output when a read operation is unsuccessful — it saw an image but could not decode a valid code. Most NO READs come down to focus for the working distance or the code type (symbology) not being enabled, so start there before suspecting hardware.

Focus is set for one working distance

The Lector's field of view is determined by the focus position, the lens focal length, and the working distance, and critically: the focus position is valid for one working distance and the device does not auto-track (no autofocus) if the working distance changes significantly. So if the code moved closer or farther than when the reader was set up, it can go out of focus and NO READ.

Set the focus

  1. Mount and align the reader at the required working distance to the code.
  2. Press the function button for 3 seconds — when the Focus LED lights up, briefly press the function button once to activate Focus mode, or let the Auto-Setup function set the focus position automatically at the current working distance.
  3. If your model uses a manual focus adjustment tool, do not over-force it — excessive force damages the product.

Enable the code type

In SOPAS ET (SICK's configuration software, use version 3.0 or above), open the reader's configuration and make sure the relevant code types are activated on the code/symbology register tab. A reader trying to decode a symbology that isn't enabled will NO READ every part.

Step-by-step

  1. Confirm the working distance matches what the reader was set up for; if the part or reader moved, re-set focus at the current distance (function-button Focus mode or Auto-Setup).
  2. Check the symbology — in SOPAS ET, verify the code type on the label is enabled.
  3. Check presentation — code contrast, damage, quiet zone, glare, and lighting; a marginal or damaged code reads intermittently.
  4. Verify the trigger/output wiring so the NO READ/GOOD READ signals reach the line correctly.

When it's really hardware

Only after focus, symbology, and code presentation check out should you suspect the lens, illumination, or reader. In SOPAS ET, view the live image and read result — a sharp image that still NO READs points to symbology/quality; a blurry image points to focus/working distance.

Key points

  • NO READ = an image was captured but no valid code decoded; check focus and code type before hardware.
  • The Lector focus is valid for one working distance and does not autofocus — a moved part/reader goes out of focus.
  • Set focus at the current working distance: hold the function button 3 s, then briefly press once at the Focus LED, or use Auto-Setup.
  • In SOPAS ET (v3.0+), enable the relevant code type on the symbology register tab — a disabled symbology NO READs every part.
  • Also check code contrast/damage/quiet zone and trigger/output wiring; a sharp image that still fails points to symbology, a blurry one to focus.

Codes and symptoms

NO READ — Unsuccessful read
An image was captured but no valid code decoded — commonly wrong focus for the working distance or a disabled code type.