Quality Of Data Matrix Codes; Qr Codes - Siemens SIMATIC MV500 Operating Instructions Manual

• Resistant to interference patterns (grooves, granularity) in the area of the code
• Wide tolerance of contrast fluctuations.
• Wide range of imaging sizes from 5 to 35 pixels per cell.
• Light shadows or shiny areas in cells are tolerated. The polarity of the cells compared with
the background must not, however, become inverted within a code.
• The ratio of the distance to the closest neighbor and the diameter of any cell can be
between 2 and 0.8.
• Although code dots must be printed according to a regular square grid pattern, individual
points can be displaced from their ideal position by up to 1/3 of the grid unit. Even slight
parallelogram-shaped distortions during printing are tolerated.
• With large-image but small-dimensioned codes, slight curves in the printed material
surface are tolerated. With larger dimension codes (for example, more than 14 x 14) or a
strongly inclined sensor axis, curves are not allowed.
• Large tolerance of background disturbances that cannot be described quantitatively
• Large tolerance of poor contrast conditions
• The optical reader reads codes with a maximum code dimension of 72 x 72 cells.
3.1.2.2

Quality of data matrix codes

The standard recognition process of the optical reader allows reliable and fast reading of
printed data matrix codes of good quality.
Range of application
• In this mode, the read rates achieved are higher than those when reading complex codes.
• The range of image sizes is from 1.5 to 35 pixels per cell. The range is static.
• The cells do not overlap or only slightly, nor are the majority isolated.
• The distortions are minimal, for example due to installation of the optical reader at an
angle.
• There are no or only a few foreign objects in the area of the code.
• There are no interference patterns (grooves, granularity) in the area of the code.
• Fluctuations in contrast are slight.
3.1.2.3

QR codes

Note
Maximum code dimension/unsupported code types
• Codes with a maximum code dimension of 89 x 89 can be read.
• The following code types are not supported: Micro QR code, Macro QR code.
SIMATIC MV500
Operating Instructions, 03/2021, C79000-G8976-C494-05
Image processing
3.1 Code reading (1D/2D codes)
39