77
12 Interface
77
Interface
Chapter
12
■Connection of RS-485
Two-wire (point to point)
- Use twisted pair wires for connection cables. (Noise margin increases.) However, two-core
parallel cables are sufficient for short-distance connection.
- Install the included terminator to the F325 if the F325 is a dead end.
- SG terminal (B10 terminal) is a ground terminal (which protects circuits) used on the circuit.
SG terminal is not normally required to use if the main unit of the F325 and connection
counterpart device are class D grounded.
However, in case connection is necessary based on the on-site conditions, check the
specifications of the counterpart device and connect it.
Two-wire (multi point)
A-
B+
A
B
A
B
A-
B+
F325
PLC・
programmable display unit and so on
Terminator
(Master) (Slave)
* Logic
- Mark state (OFF)
V
A
－ V
B
＜－ 0.2V
- Space state (ON)
V
A
－ V
B
＞ 0.2V
V
A
A- terminal voltage
V
B
B+ terminal voltage
Terminator
(accessory)
Depending on master devices, A and B may be reversely indicated.
In case that communication is not possible, switch A and B.
Attention
A
B
A- B+ A- B+ A- B+ A- B+
Twisted pair wire
F325 F325 F325 F325
Terminator
Terminator
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