Microscan MS-3000 User Manual page 41

Selecting:
External Edge
Serial Data
Serial Data &
External Edge
a. Continuous Read 1 Output will allow an output regardless of how Good Decode Read is set.
b. Level and Edge apply to the active logic state (positive or negative) that exists while the object is
in a read cycle, between the rising edge and falling edge. For the purpose of this discussion, ris-
ing edge is the trigger signal associated with the appearance of an object and falling edge is the
trigger signal associated with the subsequent disappearance of the object.
First trigger
An object, m ov ing in
1
front of the detector
beam , causes th e
first trigger (rising
O bject edge trigger) signal
detector
to be sent to th e
dec od e r, initiatin g
the read cy cle.
1
Sec ond trigger
T he sam e o bjec t,
O bject
m ov ing out of the
detector
detector's be am ,
c au ses a se co nd
trigger (f alling edge
trigger) signal to be
sent to th e decoder,
ending the read cy cle.
Figure 2-1 External Level Trigger Signals
MS-3000 Single Head Decoder User's Manual
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Has this effect:
As with Level, Edge allows a read cycle to be
initiated by a trigger signal from an object detector
when it detects the appearance of an object (rising
edge). But unlike Level mode, the removal of an
object (falling edge) does not end the read cycle.
With Edge enabled, the read cycle ends with a good
read, a timeout, or a new trigger (figure
The decoder accepts an ASCII character from the
host or controlling device as a trigger to start a read
cycle.
The decoder accepts either an external trigger or a
serial ASCII command to start a read cycle.
First rising edge trigger
O bj ec t #1 , m o v i ng in
1
f r o n t o f t h e d et e c t o r
be a m , c a u se s th e f irst
trig g er (ris i ng ed ge
tri gg e r) sig na l t o b e se n t
O bject
to t h e d ec od e r, in it i at i n g
detector th e re ad cy c le .
Subsequent rising edge trigger
2
O bject #2, m ov ing in front of
the detec tor's bea m , caus es
a second trigger (rising edge
O bject
trigger) signal to be sent to
detector
the dec oder.
This signal initiates a new
read cy cle a n d ends the
prev ious read cy cle p ro vid e d
that N ew T rigger or T im eout
and N ew T rigger is en abled
and a good read or tim eo ut
has not already o c curred.
Figure 2-1 External Edge Trigger Signals
-1).
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