Wiring For Communication In Accordance With Rs-485 - Mitsubishi Electric FX3U-232-BD User Manual

FX Series PLC User's Manual - Data Communication Edition
Non-Protocol Communication (RS/RS2 Instruction)
4.3.3

Wiring for communication in accordance with RS-485

One-pair wiring and two-pair wiring (for RS-422) are applicable for communication in accordance with RS-
485. Perform proper wiring according to the external equipment.
1. One-pair wiring
Communication
equipment operating
in accordance with RS-485
SDA
(TXD+)
SDB
Terminal
(TXD-)
resistor:
110 
RDA
*3
(RXD+)
RDB
(RXD-)
LINK
SG
*1. Make sure to perform Class-D grounding on the shield of a twisted pair cable connected to the FX
485-BD, FX
*2. Make sure to connect the
D grounding.
*3. If the grounding terminal is not provided in the PLC, perform Class-D grounding directly.
*4. Make sure to provide a terminal resistor at the end of each line.
• The FX
Set the terminal resistor selector switch accordingly.
• The FX
together with terminal resistors.
When using the FX
485-BD has a full-duplex interface.
FX -485ADP
0N
SDA
(TXD+)
SDB
(TXD-)
RDA
(RXD+)
RDB
(RXD-)
LINK
SG
FG *2
(resistance: 100  or less)
-485-BD, FX -485-BD, FX
1N 3G
FG
terminal to the
-485-BD and FX -485ADP(-MB) have a built-in terminal resistor.
3U 3U
-485-BD, FX -485ADP, FX
3G 0N
-485-BD, signal loop between the PLC and the external device occurs since the FX
2N
FX -485-BD,FX -485-BD,FX
3U 3G
FX -485-BD,FX -485ADP(-MB)
1N 3U
SDA
(TXD+)
SDB
(TXD-)
RDA
(RXD+)
RDB
(RXD-)
SG
Class-D grounding
(resistance: 100  or less)
*1
-485-BD, FX -485ADP or FX
3U 2NC
(grounding) terminal in the PLC requiring Class-
-485ADP, FX -485-BD and FX
2NC 2N
4.3 Connection Diagram
-485-BD
2N
FX -485ADP
2NC
SDA
(TXD+)
SDB
(TXD-)
RDA
(RXD+)
RDB
(RXD-)

SG
Class-D grounding
*1
-485ADP(-MB).
3U
-485-BD are supplied
1N
4 Wiring
A
B
C
Terminal
resistor:
110 
*3
D
- E
2N
F
-
2N
G
H
I
Apx.A
F-35