Hardware manual

Impact Reference Guide Camera
2-25 Datalogic Automation Inc.
Because the maximum trigger input rate of the Line Scan camera is 20 MHz, which is faster than the cam-
era’s number of lines per second acquisition rate, an internal frequency converter can be configured that will
scale the line trigger input rate up or down to create fractional scale factors. This way you can match the x
and y resolutions without modifying the encoder frequency. The Frequency Convertor setting can be used
with any of the three Line Trigger types.
Refer to the M-Series Processor and Camera Guide (843-0138) for each Line Scan camera’s maximum lines
per second acquisition rate.
The Line Trigger Multiplier and Line Trigger Dividers are integer scale factors. They can be combined to
create a fractional scale factor. For example, if the trigger input rate is 3000 and the desired lines per second
is 2000, then the Multiplier value would be 2 and the Post-Divider would be 3.
3000 * (2/3) = 2000
Pre-Divider
This setting is used to the scale the frequency down to less than 30 KHz, the maximum value for the Multi-
plier field. For example, if the trigger input rate is 30 KHZ, the pre-divider value would be 10. Using the
example above:
30000/10 * (2/3) = 2000
Example
Here is an example using the M550 line scan camera to acquire an image of a cylindrical-shaped object.
The M550 camera has a resolution of 2048 lines. The Field of View (FOV) is 41 mm and the object has a
circumference of 73 mm. The encoder produces 2500 pulses per revolution.
The horizontal resolution is
FOV/ camera resolution or 41 mm/2048 = 0.020 mm/pixel
The vertical resolution is
circumference / encoder frequency or 73 mm/2500 = 0.029 mm/pixel
Because the horizontal and vertical resolutions are different, the resultant image would appear stretched or
compressed. To correct for this we set the Pre-Divider, Multiplier, and Divider to create a fractional scale
factor.
Pre-Divider = 0, Multiplier = 29, and Post-Divider = 20
Use these values to adjust the number of lines to acquire:
Circumference * Multiplier / Post-Divider: 2500 * 29/20 = 3625 (If this result is greater than 4095 the
resolution must be changed, since the maximum number of lines is 4095.)
Recalculating the vertical resolution using the new number of lines:
73/3625 = 0.020mm/pixel
Dalsa Frequency Converter
The Dalsa camera has a frequency converter for the Line Trigger input. It has a multiplier and a divider, but
not a pre-divider. The multiplier value is fixed at 256. The divider value can be adjusted to any value
between 1 and 65535, so it allows for 0.25% accuracy in setting the pixel height.
Advanced Tab
Testing