KEYENCE N-400 - Manual (Page 66)

Chapter 4 Multi-Drop Link Mode Control Procedure
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4.1 Multi-Drop Link Mode
4.1.1. Controlling multi-drop link mode
Multi-drop link mode can control up to thirty-one BL series units through a host
computer.
Since the complex communication (RS-485 communication) between each BL
series unit and the N-400 is controlled by the N-400, the host computer controls the
communication with the N-400 only, and consequently can be operated with a
simple program. (The ID number assigned to the header of the transmitted data
allows you to identify the BL series unit that sent the data.) Therefore, multi-drop
link mode provides a system configuration that allows use of a simpler program on
the host computer.
The procedures for controlling the N-400 through a host computer are classified
into the following three methods:
• Data communication: Used to send bar code data read by the BL series to the
host computer.
• Command communication to the BL series: Used to send commands to the BL
series.
• Command communication to the N-400: Used to control the N-400 directly or
change the settings of the N-400.
* All of the above communication is performed using ASCII codes.
Details on these control methods are described on the following pages.