Rs485 Interface (Id Rw02.10-B) - OBID ID RW02.10-AD Montage Und Installation

®
OBID

4.6 RS485 Interface (ID RW02.10-B)

With RS485 data buses, it can be necessary to use terminating resistors. For each installation,
checks should be made as to whether it is necessary to use terminating resistors, because this
e.g. is dependent on line lengths, bus structure, powering of the Readers and the employed host
computer. Generally, a terminating resistor is only required at the end of the bus, i.e. on the last
unit. In order to do this, the Jumper needs to be pit on X2 terminals 1 and 2 (see Fig. 7 and Fig.
10)
To operate the bus, you need a host computer with a terminating resistor and active termination. A
twisted paired or stranded wire is recommended.
Host
(with active termination)
If no host computer with active termination is available, a active termination can be implemented as
an alternative at maximum one Reader. The Jumpers X3 and X4 are available to this.
1 2 3
without termination
(default)
Page 24 of 28
Installation
ID RW02
X2
R/A
T/B
B
A
without termination
Fig. 10 data bus with RS485 interface
X2
X3
X4
1 2 3
with termination
resistor
Fig. 11 Jumper positions of the RS485 interface
Fig. 12 intern construction of the RS485 interface
ID RW02
X2
T/B R/A
X2
X3
X4
active termination and
termination resistor
X4 +5V
1 kΩ
1
1
X2
100Ω
1
1 kΩ
X3
GND
ID RW02.10-AD/-B
ID RW02
X2
R/A
T/B
with termination resistor
X2
X3
X4
1 2 3
T / B
R / A
FEIG ELECTRONIC GmbH