Figure 4-2 Trigger Edge - Microscan MS-3 Manual Book

Chapter 4
External Trigger Edge
Definition: External Trigger Edge, as with Level, allows the read cycle to begin
when a trigger (change of state) from an external sensing device is
received. However, the passing of an object out of sensor range does not
end the read cycle. The read cycle ends with a good read output or,
depending on End of Read Cycle setting, a timeout or new trigger
occurs.
Usage: This mode is highly recommended in any application where conveying
speed is constant or if spacing, object size, or timeouts are consistent.
1
Object
detector
2
Object
detector
Serial Cmd: <K200,3>
Important: 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. Rising edge is the trigger signal associated with the appearance of an object.
Falling edge is the trigger signal associated with the subsequent disappearance of the
object.
MS-3 Laser Scanner User's Manual
Initiate Read Cycle:
Object # 1, moving in front of the detec-
tor beam, causes a change in the trigger
state, initiating the read cycle.
Initiate Second Read Cycle:
Object # 2, moving in front of the
detector beam, causes another
change in the trigger state. This
signal initiates a new read cycle
and ends the previous read cycle
unless Timeout is enabled and a

Figure 4-2 Trigger Edge

Read Cycle/Trigger
Positive
0
Associated waveforms assume
External Trigger State is set
to Positive.
Positive
0
4-7