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MELSEC-Q
5 SETTINGS AND PROCEDURES UP UNTIL OPERATION
5.5.2 Connecting to the RS-422/485 interface
Here connection precautions and an example of connection when using the QD51
(-R24)'s RS-422/485 interface are shown.
(1) Precautions when connecting
(a) When the QD51 (-R24)'s SG signal and FG signal are connected to the
external device, make connections in accordance with the external device's
specifications.
(b) Connect the shield of the connection cable to the FG terminal of either one
of the devices being connected.
If data communications cannot be done normally due to external noise,
even when wiring connections are done as shown above, make wiring
connections as shown below.
1) Connect the FG terminals of both sides with the connection cable's
shield.
However, make the connection on the external device side in
accordance with the external device's instruction manual.
2) Connect the QD51 (-R24)'s (FG) to the FG terminal of the power
supply module in the station where the QD51 (-R24) is installed, or
connect it to the FG terminal on the control panel where the QD51 (-
R24) station's programmable controller is installed.
3) Connect the nnA and nnB of each signal in the connection cable in
pairs.
Correspondence between the RS-422/485 terminal block and signal positions
Shield
QD51 (-R24) Side
External Device Side
SDA
SDB
RDA
RDB
SG
(FG)
(FG)
RDA
RDB
SDA
SDB
SG
FG
SG
FG
FG
SDA
SDB
RDB
RDA
Summary of Contents for QD51
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