Microscan MS-890, User Manual, Page: 77 / 308

MS-890 Industrial Automation Scanner User Manual
4-7
Read Cycle
External Trigger Level
Important: Level and Edge apply to the active logic state ( Open or Closed ) 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.
Note: In External Trigger Level , sending a non-delimited start serial character will start a
read cycle and sending a non-delimited stop serial character will end it. See Start Character
(Non-Delimited) and Stop Character (Non-Delimited) on page 4-13.
Usage: This mode is effective in an application where the speeds of the conveying
apparatus are variable and the time the scanner spends scanning each object
is not predictable. It also allows the user to determine if a No Read has
occurred.
Definition: External 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.
Serial Cmd: <
K200, 2
>
Initiate Read Cycle:
Object #1, moving in front of the
detector beam, causes a
change in the trigger state,
which initiates the read cycle.
End Read Cycle:
The same object, moving out of
the detector beam, causes
another change in the trigger
state, which ends the read cycle.