B&B Electronics 485DRCI - Quick Start Guide User Manual
Product overview, Set dip switches, Wire the converter
1
Set DIP Switches
2
Communications Mode
Switch
1
2
3
4
RS-485 2-Wire
Half Duplex
ON
ON
ON
ON
RS-485 4-Wire
Full Duplex
ON
OFF OFF
OFF
RS-422 Full Duplex
OFF OFF OFF
OFF
Product Overview
Wire the Converter
Pre-defined timeouts are set using switches 8
through 12. Resistor selectable baud rates are set
by inserting a through hole resistor (R-11) on the
circuit board. Timeout selections are equal to one
character time at the indicated baud rate. Setting the
converter to 9600 will generally work at 9600 and
higher baud rates. In RS-422 mode, timeouts are not
required.
3
RS-422/485 Timeout
RD LED
DB9 Port
Terminal
Block
TD LED
Power LED
Built-In Termination Resistor
Switch
5
Use built-in 120Ω Termination
ON
Use External or No Termination
OFF
Built-In Transmit Bias Resistor
Switch
6
Use External or No Bias Resistor
OFF
Use built-in 1.2K Ω Transmit Bias Resistor
ON
Built-In Receive Bias Resistor
Switch
7
Use External or No Bias Resistor
OFF
Use built-in 1.2K Ω Receive Bias Resistor
ON
DB9 Pinout
A
B
C
D
E
A
B
C
D
E
GND
Data B (+)
Data A (+)
GND
RDB (+)
RDA (-)
TDB (+)
TDB (-)
Your Device
Your Device
485DRCI
485DRCI
RS-485 2-Wire
RS-422/485 4-Wire
DIP Switch RS-422/485 4-Wire
1
2
3
4
5
6
7
On/Off
OFF
OFF
OFF
...
...
...
Position 1 = ON for RS-485, OFF for RS-422
Positions 5,6,7 are used for termination and biasing
Positiobs 8 -12 are used to set baud rate
DIP Switch RS-485 2-Wire
1
2
3
4
5
6
7
ON
ON
ON
ON
x
x
x
Positions 5,6,7 are used for termination and biasing
Positions 8 -12 are used to set baud rate
Switch Selectable
Baud
(Kbps)
8
9
10
11
12
Timeout
(ms)
2.4
ON
OFF
OFF
OFF
OFF
4.37
4.8
OFF
ON
OFF
OFF
OFF
2.03
9.6
OFF
OFF
ON
OFF
OFF
1.02
19.2
OFF
OFF
OFF
ON
OFF
0.57
38.4
OFF
OFF
OFF
OFF
ON
0.27
Resistor Selectable
Baud
(Kbps)
8 thru 12
R11 Value
Timeout
(ms)
1.2
OFF
820 KΩ
8.32
57.6
OFF
16 KΩ
0.16
115.2
OFF
8.2 KΩ
0.08
4
Loopback Test
Configure for RS-485 Four wire,
9600 baud. Jumper terminals B to
D and C to E. Connect a PC to the
RS-232 port Using HyperTerminal
or similar program, connect to the
appropriate COM port.
(Remember to set the baud rate to
9600.) Turn off HyperTerminal local
echo. Transmit data. The same data
should be returned.
A
B
C
D
E
10 to 48 VDC, 0.2 A
485DRCI
5
Check LEDs
LEDs
Power LED
Red. ON when power is applied
Data LEDs
Green, LEDs flash when data is present on the port