Rs485 Cable Connection - Toshiba V Series User Manual

Chapter 3 Connection

3.2 RS485 Cable Connection

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10
Ch1 of the ASCII module can be connected RS485 transmission.
The following figure shows the cable connection.
FG
RXDA
RXDB
TXDA
TXDB
SG
External device
Notes
(1) Be user to connect SG (signal ground).
(2) Use shielded twisted-pair cable and connect to FG (ground) at the ASCII module.
(3) Be sure to connect the A (+) and B (-) of each signal of the twisted-pair cable in pairs.
(4) On the RS485 device, connect a terminating resistors. If there is no connecting device,
connect a 120 Ω (1/2 W) resistor at the end.
(5) The transmission polarity may be different on some RS485 external devices.
In this case, transmission may be possible by exchanging A(+) and B(-).
(6) Although it depends on the transmission speed, wires with size greater than 0.5 mm
should be used in order to keep the transmission impedance low.
(7) RS485 supports only four wire. Multiple transmission ports cannot be connected because
ASCII TXA/TXB do not become tristate (open) once transmission is performed. Two wire
RS485 cannot be connected.
1 FG
10 TXDA
21 TXDB
11 RXDA
22 RXDB
7 SG
12 RTSA
23 RTSB
13 CTSA
24 CTSB
ASCII module
model 3000 ASCII Module (AS311) User's Manual
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