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Trigger Mode

4-6 MS-3 Laser Scanner User’s Manual

4–Read Cycle/Trig-

Object

detector

Object

detector

Positive

External Trigger Level

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

Definition: External Trigger Level allows the read cycle to begin when a trigger

(change of state) from an external sensing device is received. The read

cycle endures until the object moves out of the sensor range and the

active trigger state changes again.

Usage: This mode is effective in an application where the speeds of the convey-

ing apparatus are variable and the time the scanner spends scanning

each object is not predictable. It also allows the user to determine if a

noread has occurred.

Serial Cmd: <K200,2>

Figure 4-1 Trigger Level

Initiate Read Cycle:

Object # 1, moving in front of the

detector beam, causes a change in the

trigger state, initiating the read cycle.

End Read Cycle:

The same object, moving out

of the detector beam, causes

another change in the trigger

state, ending the read cycle.

Associated waveforms assume

External Trigger State is set

to Positive.

Figure 4-1 Trigger Level

1 2 ... 49 50 51 52 53 54 55 56 57 58 59 ... 201 202

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Microscan MS-4 Especificações Página 54