Instruction Manual

2-30
Installation
2
2-6 BL-U1 Connections and Wiring
Wiring an RS-485
Use the [SDA] and [SDB] on the BL-U1 terminal for wiring.
• Up to 31 BL-U1 units can be connected in multi-drop link mode.
• The total length of the RS-485 cable should be under 1.2 km.
• *Set the terminator (100 ) for each end of the RS-485 connection (marked with * above) to on.
Use the dipswitch to turn the BL-U1 terminator on or off.
"BL-U1 Dipswitch Settings" (Page 2-27)
The terminator switch can be used to turn the N-410 terminator on or off.
"N-410" (Page 1-5)
Be sure that the RS-485 cable is not connected through a transient terminal.
• Do not run this through the same ducts as the power line.
• Do not branch the RS-485 connections as shown below.
SDA
BL-U1
*
SDB
SG
SDA
BL-U1
SDB
SG
SDA
BL-U1
SDB
SG
RS-485 +
RS-485 –
RS-485 SG
*
N-410
Recommended RS-485 cable (shielded)
Maker: Furukawa Electric Co., Ltd.
Part name: Instrumentation cable
Model: KPEV-SB(1P) 0.75 mm
2
Note
BL-U1 BL-U1
BAD GOOD
Note
BL-U1 BL-U1 N-410
BL-U1
BL-U1 BL-U1 N-410
BL-U1
*
*
* Terminator turned on
BAD (Branched) GOOD (Not branched)