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23
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7) Connections of low order communication RS-485
Example of connection 1
KR3000
Low order
communication terminal
AL3000 etc.
SE3000,MELSEC etc.
SG
RDB
RDA
SDB
SDA
SG
SB
SA
Termination
resistor
100
Ω
1/4W
SG
RDB
RDA
SDB
SDA
To ensure the transmission of data via RS-485 communications, mount a termination resistor at both
ends of transmission lines. When the protocol converter (SC8-10) is at an end of a transmission
circuit, short the terminals of
4
and
5
of the unit to insert the termination resistor automatically.
Mounting termination resistor
Remarks
RD
SD
SG
RDA
RDB
1
2
3
4
5
6
7
8
Protocol converter
(SC8-10)
Within 15m
Within 1.2km
RD
SD
SG
2
3
9
This recorder
SDA
SDB
SG
RDA
RDB
Example of connection 2 (SYSMAC)
SYSMAC
CPU unit
Internal RS-232C port
(D-SUB 9-pin receptacle)
RS-232C
RS-485
SDA
Transmitting
data
SDB
Receiving
data
SDA
Internal
circuit
RDB
RDA
Termination
resistor
100
Ω
1/4W