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5.7.2
Wiring and configuration of RS-485 terminals
RS-485 terminal layout
Terminating resistor switch
Initially-set to "OPEN".
Set only the terminating resistor switch of
the remotest converter unit to the "100 Ω" position.
P5S
SG
SDA1
(VCC)
(GND)
(TXD1+)
OPEN
VCC
GND
+ TXD
VCC
GND
+ TXD
100Ω
P5S
SG
SDA2
(VCC)
(GND)
(TXD2+)
Name
RDA1 (RXD1+)
Converter unit receive +
RDB1 (RXD1-)
Converter unit receive -
RDA2 (RXD2+)
Converter unit receive + (for branch)
RDB2 (RXD2-)
Converter unit receive - (for branch)
SDA1 (TXD1+)
Converter unit send +
SDB1 (TXD1-)
Converter unit send -
SDA2 (TXD2+)
Converter unit send + (for branch)
SDB2 (TXD2-)
Converter unit send - (for branch)
P5S (VCC)
5 V (permissible load current 100 mA)
SG (GND)
Earthing (grounding) (connected to terminal SD)
Connection of RS-485 terminals and wires
• The size of RS-485 terminal block is the same as that of the control circuit terminal block. Refer to
method.
NOTE
• To avoid malfunction, keep the RS-485 terminal wires away from the control circuit board.
System configuration of RS-485 terminals
• Computer and converter unit connection (1:1)
Computer
RS-485
interface/
terminals
SDB1
RDA1
RDB1
(TXD1-)
(RXD1+)
(RXD1-)
-
+
RXD
-
-
+
RXD
-
SDB2
RDA2
RDB2
(TXD2-)
(RXD2+)
(RXD2-)
Description
Converter
unit
RS-485
terminals
∗
Twisted pair cable
Computer
Maximum
RS-232C
15 m
cable
Converter
∗Set the terminating resistor switch to the "100 Ω" position.
5.7 (N) Communication operation parameters
page 48
for the wiring
Converter
unit
RS-485
terminals
∗
Twisted pair cable
5. PARAMETERS
1
2
3
4
5
6
7
8
9
10
115
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