CALIBRATION CARD FAQ
What do calibration cards do? Calibration is the process of mapping a camera’s measurement to actual reflectance levels. To be ISO compliant, a verifier must have a calibration process.
How often do you need to calibrate? Every company has their own policy on how often to calibrate, we recommend every 30 days.
How often do you need to purchase a new calibration card? Calibration cards expire after 2 years from the in-use date. Cards should be safely stored away from dust and direct sunlight when not in use.
What does conformance calibration card mean? The card contains “Conformance Test Symbols” with intentional imperfections. When you verify these symbols, you can check the reporting capabilities of the verifier and confirm that the verifier conforms to industry standards such as ISO/IEC 15415, ISO/IEC 15426-2. Since these cards can be used as a quick way to double-check that the verifier is working properly, some companies have written requirements to use them in their quality processes. Certain industries also require the use of a card with conformance test symbols, those industries list the requirement in their application standards.
Does it matter what kind of symbology is used when calibrating? Calibration is not specific to the symbology and once the verifier is calibrated using either type of calibration target, the verifier is calibrated for both 1D and 2D barcodes.
Can we do a conformance test when grading against ISO/IEC TR 29158? There are no DPM-specific calibration cards to challenge the ISO TR 29158 standard. A data matrix conformance test card can be used, but the contrast values will never perfectly match the value on the card because of the image adjustment used in the ISO TR 29158 standard. It is recommended that the verifier also be tested using the ISO 15415 standard. Testing with the ISO TR 29158 grading standard can be done to check for correct operation but will yield results that are different than those shown on the conformance card.
Where can we check calibration results? Check to see that the verifier is returning the correct Rmin/Rmax values (sometimes labeled RL and RD) by verifying the test symbol as you would normally verify a code. The values are found next to the Symbol Contrast grade in the Quality Detail section of the report and on the user interface. These values should match those shown on the card with allowance for a small amount of tolerance. Other parameter values can likewise be checked and compared to the expected values on the conformance test card.
DMV-AICC
Applied Image #AI-CCS-UPC/EAN 6 mil UPC/EAN Calibrated Conformance Standard Test Card. (This is most similar to discontinued item #1556 (GS1 EAN/UPC Calibration Card)).
DMV-DMCC
Applied Image Data Matrix Calibration and Conformance Symbol
DMV-CCC
Cognex Calibration Card contains Master Grade 1D and 2D symbols. For calibration only, does not contain any ISO/IEC 15426 conformance test symbol.
To order a new calibration card, please call us at (855) 426-4639 or e-mail us at verifiers@cognex.com.
Currently, all GS1 calibration cards are out of stock and discontinued.
