KEYENCE N-400 - Manual (Page 33)

Chapter 2 Installation Procedure
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2.4.5 Connecting RS-485
For the RS-485 connections, use the “SDA” and “SDB” terminals provided on the
terminal block.
Recommended RS-485 cable
• 0.75 mm 2 x 2 cores, shielded
• Up to thirty-one BL-U1 (BL series) units can be connected in multi-drop link
mode.
• The total extension length of the RS-485 cable must be within 1.2 km.
• Turn ON the equipment terminator (termination resistance: 100 Ω ) at both ends
of the RS-485 connection (marked with * in the above diagram).
• Turn ON/OFF the BL-U1 terminator using the terminator switch. (See p. 22.)
• Turn ON/OFF the N-400 terminator using the terminator switch. (See p. 6.)
Note: Be sure not to connect the RS-485 cable using the terminal block.
Note 1: Do not place the RS-485 cable in the same conduit as a power cable.
Note 2: Do not branch the RS-485 connection as shown below.
SDA
BL-U1 BL-U1 BL-U1
* N-400
SDB
SG
SDA
SDB
SG
SDA
SDB
SG
RS-485 +
RS-485 –
RS-485 SG
*
Incorrect Correct
BL-U1 BL-U1
BL-U1 BL-U1
BL-U1
BL-U1 BL-U1
BL-U1
N-400 N-400
*
*
* Terminator ON
Incorrect
(Connection with branch) Correct
(Connection without branch)