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Scanner Card Interface > Description > Measures & Coordinates

Measures & Coordinates
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If not otherwise noted, all measures are given in the units listed in the table below.

Measure

Unit / Range

time

microsecond (us)

speed

bits / second (based on scanner range)

scanner range

0..65535 bit

analog value

0..255 bit

8 bit port

0..255 bit

coordinates

values in configured field

Table 4: Units

Coordinates:

The SAM library does not used a fixed coordinate system for scanner positions. It allows the user to configure an arbitrary field size and specify coordinates (and speeds) relative to this field. The library then internally calculates the bit values sent to the scanner. Example with 400mm field size and 100mm position:

position: 100mm * 65535bit / 400mm = 16383bit

This enables the usage of coordinates that correlate to the actual field of a physical scanner. If it is desired to specify coordinates in bits, set the field sizes from -32768 to 32767 in both directions. Note that the actual bit values sent to the scanner are also influenced by the gain and offset settings.

The SAM library also uses a so-called working area to validate coordinates during object marking. This has no relevance when doing low level marking through the scanner card interface. Simply set the working area to the same size as the field.

note

Set/GetField

Set/GetWorkingArea