KEYENCE BL-180 - Manual (Page 97)

Power Supply BL-U1
91
3 Outline of Multidrop Link
3.1 Multidrop Link
The multidrop link is a communication method to control several BL series read-
ers simultaneously with one host computer as shown in the system configuration
on page 79.
Using the RS-485 cable as the communication path, the multidrop link offers high
noise immunity and enables long-distance transmission. The multidrop link allows
easy wiring using twisted-pair cables (2-wire).
3.2 System Configuration
To use the multidrop link, a BL series reader plus the following equipment is re-
quired.
BL-U1
To use the multidrop link, be sure to use this power supply unit.
RS-485/RS-232C converter
To connect a BL series reader to the host computer, the RS-485 signal must be
converted into an RS-232C signal.
Host computer
Use a personal computer with an RS-232C interface.
When several BL readers are reading several bar codes, the amount of data to
be processed may exceed the host computer’s capacity.
To prevent this, reduce the number of the BLs connected to the host computer,
or replace the host computer with another one which provides higher data
throughput (including processing of the programming language).
2-wire twisted-pair cable for the RS-485 interface.
Prepare the specified cable (see page 88).
RS-232 cable
Cable used to connect the host computer to the RS-485/RS-232C converter.
Use a cable whose pin assignment conforms to those of the RS-232C connector
of the host computer and the RS-485/RS-232C converter.