READING FEATURES10166.5 MAXIMUM LINE SPEED AND EXPOSURE TIME CALCULATIONSThe Exposure Time (or Shutter) parameter defines the time during which the image will beexposed to the reader sensor to be acquired. This parameter depends heavily on theenvironmental conditions (external lighting system, image contrast etc.).In general, a longer time corresponds to a lighter image but is susceptible to blurring due tothe code movement; a shorter exposure time corresponds to a darker image.NOTE: The following considerations must be applied only when the internallighting system and 2D codes are used. The Maximum line speed allowed forlinear codes or postal code reading applications heavily depends on thedirection of symbol movement. When the direction of movement is parallel tothe elements of the code, the maximum speed is greater.Assuming: X: Code Resolution (mm) Texp: Exposure Time (s) LS: Line Speed (mm/s)The essential condition to avoid blurring effects between two adjacent elements in a dynamicreading application is:LS Texp XThe maximum (theoretical) line speed LS can be calculated as follows:X / Texp (max) = LS (max)Example:A Matrix 300™ using:Internal Lighting Mode = Very High Power StrobeExposure Time (x1s) = 100 (100s)Code Resolution (X) = 0.254 mm (10 mils)has a maximum line speed of:0.254 (mm) / 0.0001 (s) = 2540 mm/sLikewise, Texp (max) is the maximum Exposure Time value that can be used without blurringfor the given application line speed and code resolution. Therefore:X / LS (max) = Texp (max)
