64
5-5
Wiring
Transmission Lines
Masters, Slaves and Remote Interfaces are connected using 2-conductor
cable in the manner shown below.
Master
Slave
Slave
Terminator switch OFF
Terminator switch OFF
Remote Interface
I/O Block
Terminator switch ON
1.
All 2-conductor cable used for connections must be 0.75 mm VCTF (vi-
nyl cabtire fiber cable).
2.
Connect positive to positive, negative to negative.
3.
Do not wire a Master directly to more than one other Unit; i.e., start wir-
ing at each Master and continue in order through the last Unit at the
other end of each line.
4.
Set the last Unit as the terminator.
5.
Do not branch the wiring at a Slave; i.e., wire a Slave in series to a
maximum of two other Units, one before it and one following it.
6.
The total cable length must be 200 meters or less from each Master to
its terminator.
7.
Do not run transmission lines parallel to or in the vicinity of high-voltage
or high-current lines. (Running transmission lines with normal I/O lines
or normal power lines presents no problem.)
8.
RS-485 interfaces are used for transmission lines, as shown below.
+
–
+
–
120
Ω
+
–
+
–
+
–
120
Ω
–
+
Transmission
terminals
Master
Slave (Terminator switch ON)
Slave (Terminator switch OFF)
1, 2, 3...
Wiring
Section 5-5