10.INTERFACE
146
10-5. RS-485 Communication Interface
10-5-1. Communication Specifications
◇
Specifications
Signal level
:
Based on RS-485
Transmission distance
:
Approx. 1km
Transmitting method
:
Asynchronous, Full duplex
Transmitting speed
:
1200, 2400, 4800, 9600, 19200, 38400bps selectable
Bit configuration
:
Start
: 1bit
Character length
: 7 or 8bit selectable
Stop
: 1 or 2bit selectable
Parity
: None, Odd or Even selectable
Code
:
ASCII
10-5-2. RS-485 Connection
◇
One to one connection
- Use a twisted pair cable for connection. (The noise margin will increase.) However, a twin cable
is sufficient for short-distance connection.
- Couple a terminal resistor of 100 ~ 200
Ω
to the receiving end.
- The F701-C side has internal terminal resistor. By
turning ON the Rt switch, it is not necessary to
install external resistance.
- The terminal SG is a grand terminal used on the
circuit for protecting the circuit.When the main
body of F701-C and the device connected to F701-C
are grounded by D type ground, there is usually no need to use the terminal SG.
However, confirm the specifications of the devise connected before connecting the terminal SG,
when it is necessary to connect it according to the situation of the site.
A
B
SD
A
B
RD
A
B
RD
A
B
SD
A
B
A*
B
F701-C
Sequencer,
host computer, etc.
Rt=terminal resistor
Rt=terminal resistor
(Master)
(Slave)
*
Logic
-
Mark status (OFF)
V
A
- V
B
＜
-0.2V
-
Space status (ON)
V
A
- V
B
＞
0.2V
V
A
: RD
A terminal voltage
V
B
: RD
B terminal voltage
Turn ON the Rt switch.
Some sequencer manufacturers express A and B in reverse.
If communications are unsuccessful, interchange A and B.
Request
