Verification Methods For Different Application Scenarios; Verification Of Printed Labels; Verification Of Direct Part Marks - Siemens SIMATIC MV440 Operating Instructions Manual

4.2.3

Verification methods for different application scenarios

4.2.3.1

Verification of printed labels

In 1996, the "Association for Automatic Identification and Mobility" (AIM) published the data
matrix symbology specification with an evaluation procedure for print quality. According to
this evaluation procedure, test systems could evaluate a symbol according to its degree of
acceptability (4 to 0).
The specification later became the ISO/IEC 16022 standard. This type of test was developed
for paper labels with high contrast.
It allows a quantitative measurement of the print quality and allows the testing of printed 2D
codes based on a quality standard. Here, the important fact is that the printing of a data
matrix code on paper is a high-quality process.
White paper is printed with black ink to achieve a high contrast. With this background, the
threshold values for grading in the ISO/IEC 16022 standard are very restrictive because the
marking quality is so high.
Less exacting requirements would be neither suitable nor useful in the printing industry. The
AIM standard identifies the following typical errors:
● Blocked ink jets
● Too much or too little ink
● Inconsistent application of the ink
● Inadequate contrast due to a combination of ink color and background color
4.2.3.2

Verification of direct part marks

Test procedure
In contrast to the printing process, markings applied directly to the part are not ideal as a
marking technique. Here, the important thing is that parts are optimized for their primary
purpose. It is, for example, more difficult to apply a laser mark to bare aluminum compared
with stainless steel.
Aluminum is, however, more suitable in the production of parts for aircraft because it is
lighter. The weight is therefore more important than markability. With a specimen with a
marking on aluminum, the part does not pass the test according to the ISO/IEC 16022
standard due to the low degree of contrast.
Here, a verification method suitable for DPM must be used. For open applications, a public
standard such as ISO/IEC 15415 or AS9132A should be used.
Use AIM DPM-1-2006 for applications with demanding lighting conditions. In contrast to all
other verification standards; automatic exposure control is performed here to optimally
capture the code to be verified.
SIMATIC MV420 / SIMATIC MV440
Operating Instructions, 04/2013, A5E02371045-06
Image processing
4.2 Code verification
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