5 connecting rs-485 – KEYENCE N-400 User Manual

Page 33

Chapter 2 Installation Procedure

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

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

N-400

SDB

SDA

SDB

SDA

SDB

RS-485 +

RS-485 –

RS-485 SG

Incorrect

Correct

BL-U1

N-400

* Terminator ON

Incorrect
(Connection with branch)

Correct
(Connection without branch)