Unipulse F701-P, Operation Manual

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55
9 RS-485 INTERFACE
55
R
S-
48
5
IN
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R
FA
C
E
Chapter
9
9-2.
RS-485 connection
■
Two-wire type (point to point)
- Use a twisted pair cable for connection. (Noise margin is improved.)
However, a parallel two-core cable is enough for short-distance connection.
- Install terminating resistance each on the host side and F701-P side.
- The SG terminal is a ground terminal used in circuits (to protect the circuits).
If the F701-P body and the equipment on the other end of the connection are class-D-grounded,
usually there is no need to use the SG terminal.
However, if there is a need to connect it according to the on-site situation, connect it after
checking the specifications of the equipment on the other end.
■
Two-wire type (multi point)
A
B A
B
A
B A
B
F701-P
PLC/Host like a PLC,
programmable display, etc.
Terminating resistance
(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
Terminating resistance
(accessory)
On some master equipment, A and B may be expressed in reverse.
If communication fails, interchange A and B.
Attention
A B A B
A B A B
Twisted pair cable
F701-P F701-P F701-P F701-P
Terminating
Terminating resistance
A
B
resistance
Host