User`s manual

12
(6) Connection precaution
(a) When connecting the SG and FG signals of the module to an external
device, follow the specification of the external device.
(b) Connect the connector cable shield to either one of the FG terminals
on the connected device.
(c) If data communication cannot be performed normally due to external
noise even if the wiring is done properly, install wiring as follows:
•
Connect the FGs of both stations using the connector cable shield.
As for the connection on the external device, follow the specific
manual.
Be sure to use the plate terminals included with the product when
connecting the braided shield wire to the QJ71C24N-R4.
•
Connect the FG of the module to the FG terminal of the power supply
module for the station including the module or to the FG terminal on
the control panel on which the PLC i.e., the station including the
module is installed.
•
Connect nnA and nnB in each signal of the connector cable as a
pair.
Corresponding to RS-422/485 terminal block and signal positions
Shield
Module
External device
SDA
SDB
RDA
RDB
SG
(FG)
(FG)
SDA
SDB
RDA
RDB
SG
FG
SG
FG
FG
SDA
SDB
RDB
RDA
POINT
1) When using the RS-232 to RS-422 converter or similar device for the device
corresponding to the both-end station of the line according to the explanation of
this section, set or connect a terminal resistor with the converter.
2) When connecting to the RS-422/485 interface of the module (including one-to-
n, n to one and m to n connections), be sure to use the devices that meet the
corresponding communication specifications.