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B&B Electronics 485DRCI - Quick Start Guide User Manual

Product overview, Set dip switches, Wire the converter

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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