PSC LazerData Series 9000E, Инструкция по установке и эксплуатации

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INTRODUCTION
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PRINCIPLES OF OPERATION
The LazerData Series 9000E bar code scanner/decoder uses a light
beam generated by a laser diode light source to illuminate bar code
labels. The laser beam is deflected in a fan shaped pattern across the
label. The reflected light of the laser beam, representing the light and
dark bars of the coded label, is then collected and focused by a lens
onto a photodiode, processed, then converted to a digital signal. The
signal is a close approximation of the bar code pattern as shown in
Figure 2-1. This signal is then analyzed by a high speed
microprocessor. The bars and spaces in the code are converted to the
numeric or alphabetic characters represented by the bar code symbol.
After the label is decoded, the characters are transmitted via the Host
and Local Port to an external device or host computer.
Bar Code and Digital Signal
Figure 2-1
In addition to reading the code, the scanner can compare the code that
has been read to codes programmed into it's memory and output signals
indicating that a comparison has or has not occurred. The scanner can
also accept a gate input signal indicating that a code is in position to be
read. When the gating input is used, only one data transmission is made
for each bar code presented to the scanner. The scanner also outputs
separate logic level pulses when Good Read, No Read, Good Compare
and No Compare conditions occur.