Grounding - Mitsubishi Electric FX3U-232-BD User Manual

FX Series PLC User's Manual - Data Communication Edition
Parallel Link
2. In the case of two-pair wiring
FX -485ADP
2NC
SDA
(TXD+)
SDB
(TXD-)
RDA
(RXD+)
RDB
(RXD-)
Terminal
resistor
330 

 2
SG
*1. Make sure to perform Class-D grounding on the shield of a twisted pair cable connected to
the FX -485-BD, FX
2N
*2. Make sure to connect the
Class-D grounding.
If the grounding terminal is not provided in the PLC, perform Class-D grounding directly.
4.3.3 For FX (FX) and FX
2
FX -40AW
2
SA
SB
*1
SG
*1. Connect the
4.4

Grounding

Grounding should be performed as stated below.
• The grounding resistance should be 100 or less.
• Independent grounding should be performed for best results.
When independent grounding can not be performed, perform "shared grounding" as shown in the following
figure.
Other
PLC
equipment
Independent grounding
Best condition
• The grounding wire size should be AWG 14 (2 mm
• The grounding point should be close to the PLC, and all grounding wires should be as short as possible.
FX -485-BD
2N
FX -485-BD FX -485ADP
1N 0N
SDA
SDA
(TXD+)
(TXD+)
SDB SDB
(TXD-) (TXD-)
RDA RDA
(RXD+)
(RXD+)
RDB
RDB
(RXD-)
(RXD-)
LINK
SG
SG
FG
-485-BD or FX
1N 2NC
terminal to the
FG
PLCs
2C
FX -40AW
2
SA
SB
*1
SG
terminal to the
SG SG
Other
PLC
equipment
Shared grounding
Good condition
FX -485ADP
0N
SDA
(TXD+)
SDB
(TXD-)
RDA
(RXD+)
RDB
(RXD-)
LINK
SG
FG *2
Class-D grounding (resistance: 100  or less)
-485ADP.
(grounding) terminal in the PLC requiring
FX -40AP
2
T
R
terminal in each PLC (main unit).
For details, refer to the Hardware Edition of each series.
Other
PLC
equipment
Common grounding
Not allowed
2 ) or larger.
4 Wiring
4.4 Grounding
FX -485-BD
2N
FX -485-BD FX -485ADP
1N 2NC
SDA SDA
(TXD+) (TXD+)
SDB SDB
(TXD-) (TXD-)
RDA RDA
(RXD+) (RXD+)
RDB RDB
(RXD-) (RXD-)
Terminal
resistor
330 
SG

 2
SG
*1
FX -40AP
2
R
T
C-31
A
B
C
D
E
F
G
H
I
Apx.A