Mitsubishi FX3U-232-BD User Manual page 312

FX Series PLC User's Manual - Data Communication Edition
Inverter Communication
2. Connecting a terminal resistor to the FX PLC
Connect a terminal resistor between the RDA and RDB terminals of the communication equipment.
3. When using the FX
The FX -485-BD and FX
3U
Set the terminal resistor selector switch accordingly.
330 Ω
OPEN
110 Ω
4. Connecting a terminal resistor to the inverter
Communication may be affected by noise echo depending on the transmission speed and transmission
distance. When communication is hindered by noise echo, connect a terminal resistor to the inverter.
1) When the PU connector or RS-485 connector (S500 Series) is used
- Connect a terminal resistor between pin No. 3 (RDA) and pin No. 6 (RDB).
- Connect a distributor to the PU terminal because terminal resistors cannot be connected.
- Connect a terminal resistor only to the inverter located furthest away from the FX PLC.
2) When the FR-A5NR is used in connection
- Connect a terminal resistor chip (which is supplied together with the FR-A5NR) between the RDB and
RDR terminals in the most distant inverter.
3) When the F700 or A700 Series inverter built-in RS-485 terminal is used
A terminal resistor is built into the RS-485 terminal. Set the terminal resistor switch in the F700/A700
Series inverter located at the end to "100Ω".
Terminal
resistor
switch
4.6 Wiring a Shielding Wire (Class-D grounding)
Perform Class-D grounding only to one side of a cable according to the absence/presence of the grounding
terminal.
1. When the
FG
Connect the
2. When the
FG
Perform Class-D grounding directly to the shielding wire of the cable.
E-22
-485-BD or FX
3U
-485ADP(-MB) have built-in terminal resistors.
3U
330 Ω
OPEN
110 Ω
OPEN
100Ω
terminal is provided in the communication equipment
terminal to the
FG
terminal is not provided in the communication equipment
-485ADP(-MB)
3U
Terminal
resistor selector
switch
→ For details on connection, refer to each wiring diagram.
(grounding) terminal of the PLC requiring Class-D grounding.
4.6 Wiring a Shielding Wire (Class-D grounding)
330 Ω
Terminal
OPEN
resistor selector
switch
110 Ω
4 Wiring