Mitsubishi Electric FX3U-232-BD - Grounding

C-31
FX Series PLC User's Manual - Data Communication Edition
Parallel Link
4 Wiring
4.4 Grounding
A
Common Items
B
N:N Network
C
Parallel Link
D
Computer Link
E
Inverter Communication
F
Non-Protocol Communication (RS/RS2 Instruction)
G
Non-Protocol Communication (FX
2N
-232IF)
H
Programming Communication
I
Remote Maintenance
Apx.A
Discontinued models
2. In the case of two-pair wiring
*1. Make sure to perform Class-D grounding on the shield of a twisted pair cable connected to
the FX
2N-485-BD, FX1N-485-BD or FX2NC-485ADP.
*2. Make sure to connect the terminal to the (grounding) terminal in the PLC requiring
Class-D grounding.
If the grounding terminal is not provided in the PLC, perform Class-D grounding directly.
4.3.3 For FX2(FX) and FX2C PLCs
*1. Connect the terminal to the terminal in each PLC (main unit).
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.
For details, refer to the Hardware Edition of each series.
• The grounding wire size should be AWG 14 (2 mm
2
) or larger.
• The grounding point should be close to the PLC, and all grounding wires should be as short as possible.
Class-D grounding (resistance: 100  or less)
*1

SG
FX
2NC -485ADP
FX
2N -485-BD
FX
1N -485-BD
SG
SDA
(TXD+)
SDB
(TXD-)
RDA
(RXD+)
RDB
(RXD-)

SG
FX
2NC -485ADP FX 0N -485ADP
LINK
SG
FG
*2
FX 2N -485-BD
FX
1N -485-BD
SG
FX
0N -485ADP
SDA
(TXD+)
SDB
(TXD-)
RDA
(RXD+)
RDB
(RXD-)
SDA
(TXD+)
SDB
(TXD-)
RDA
(RXD+)
RDB
(RXD-)
LINK
SG
FG
Terminal
resistor
330 
 2
Terminal
resistor
330 
 2
SDA
(TXD+)
SDB
(TXD-)
RDA
(RXD+)
RDB
(RXD-)
SDA
(TXD+)
SDB
(TXD-)
RDA
(RXD+)
RDB
(RXD-)
SDA
(TXD+)
SDB
(TXD-)
RDA
(RXD+)
RDB
(RXD-)
FG
SA
SB
SG
*1
FX
2
-40AW FX
2
-40AW
SA
SB
SG
*1
FX
2
-40AP
T
R
FX
2
-40AP
R
T
SG
SG
PLC
Other
equipment
PLC
Other
equipment
PLC
Other
equipment
Shared grounding
Good condition
Common grounding
Not allowed
Independent grounding
Best condition