KEYENCE BL-700 Series - Manual (Page 44)

Chapter 3 Functions for Reading Operation
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3.1 Read Operation
3.1.1 Scanning method
There are two methods for triggering the BL-700 to read bar codes; the “Level
signal” method and the “One-shot signal” method. The example given for these two
methods uses the “single label read mode” (
➮ see P.33), which reads one bar code
while trigger input turns on once, and uses the “after read” as the data-send mode
(
➮ see P.32).
■ Level signal trigger
When the trigger input turns on, laser emission begins and the unit begins reading.
The laser turns off after reaching the specified decode count. Then, the unit sends
the readout data.
*1. Set trigger input so that it stays on long enough for the laser beam to cover the
entire bar code.
*2. After the trigger input exceeds the preset input time, the laser begins to emit.
➮ See note on the next page.
*3. The communication time can be obtained from the following expression:
*4. The length of time that the OK/NG output is on can be changed to between 10
ms and 2.55 s.
*5. The OK/NG output turns on 5 ms after the data has been read (or trigger input
turns off in case of reading failure).
Note: 5 seconds after the power switch turns on or an UNLOCK command (
➮ see
P.90) is sent, the unit will not start reading a bar code by turning on the trigger
input.
Trigger input
Bar code
Laser beams
Communication time
OK/NG output OK/NG NG
<Succeed to read> <Fail to read>
*2
*1
*3
*4
*5
(Code length of data to be
sent + Header/number of
characters in delimiter)
X
Data bits + (1: If parity is used) + Start/stop bit
Baud rate