Datalogic Heron D140 Guide Rapide page 9

BEEPER/LED
VIDEO
ILLUMINATOR
+VCC
This scanner input drives the decoding LED,
the Good Read Spot and the beeper in the
scanner. The LED and Good Read Spot turn
on when a positive current is applied to the
pin. The beeper sound is obtained pulsating
this current at a frequency of about 2 kHz.
The maximum voltage that can be applied to
this input is 5 Vdc.
This "open collector" scanner output is
electrically identical to the barcode. It supplies
a series of pulses the length of which are
proportional to the width of the elements
within the barcode read. Video polarity is
programmable. By default a low output level
corresponds to a bar. The frequency of the
pulses depends on the density of the code,
the distance from code and the programmed
output scan frequency (see the following
figure Video and Scan signals).
A positive voltage (5 Vdc) is applied to this
input by the decoder when the decoding logic
senses the trigger is pressed; this causes the
activation of the illuminator and CCD.
This input must be connected to the positive
pin of the supply voltage (5 Vdc ± 5%). When
the ILLUMINATOR pin is positive, all the
current necessary to power the scanner flows
through +VCC.
CODE
VIDEO
SCAN
Video and scan signals