KEYENCE N-400 - Manual (Page 10)

Chapter 1 Overview of The N-400
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1.1 Functions of the N-400
The N-400 multi-drop controller allows the following functions to be added to the BL
series.
Note: The BL-U1 and N-48 can be used as an RS-232C to RS-485 converter.
However, the BL-U1 is not available in Europe.
Multi-drop link function (mode)
The N-400 can control up to thirty-one BL series units using a host computer,
enabling the multi-drop link configuration.
The communication path is an RS-485 cable, which provides high noise-resistance
and enables data transmission over a long distance (up to 1.2 km). Since a twisted
pair cable (two cables) is used for the connections, the multi-drop link configuration
can be realized with simple wiring.
The N-400 controls the complicated communication (RS-485 communication)
between each BL series and the N-400. Since the host computer works only for
communication with the N-400, it can be operated with a simple program. (The ID
number assigned to the head of the transmitted data allows you to identify the BL
series unit that sends the data.) Therefore, the host computer’s job is reduced with
this system configuration.
Multi-head scan function (mode)
If the position of bar codes is unknown in a product, or bar codes are printed in
several positions, the bar codes cannot be read with a single bar code reader. In
such cases, several bar code readers need to be mounted in various positions or at
various angles.
When the N-400 controller is used in multi-head scan mode, a host computer can
control several BL series units as if they were a single unit.
N-400
RS-485
N-48
or
BL-U1
RS-232C
Host
BL series
Sensor for
trigger input
N-400
N-48
or
BL-U1
RS-232C
RS-485
Host
BL series
* *
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