B+B SmartWorx SCP211-DFTB3 Quick Start Manual

6
Wiring Examples: RS-422 4-Wire
& RS-485 4-Wire
1. In this example, the converter is set up to use internal
bias and no termination.
RS-485 4-Wire DIP Switch RS-422 4-Wire DIP Switch
7
Bias & Termination
1. The circuit can be biased using the built in 1 kΩ pull-up
and pull-down resistors. This is controlled with DIP Switch
Position 5. The default setting is ON (bias resistors "in.")
a. When an RS-485 network is in an idle state, all nodes are
in listen (Receive) mode. Under this condition, there are
no active drivers on the network. All drivers are tri-stated.
Without anything driving the network, the state of the line
is unknown. If the voltage level at the receiver's A and B
inputs is less than ±200mV, the logic level at the output of
the receivers will be the value of the last bit received. In
order to maintain the proper idle voltage state, bias resistors
must be applied to force the data lines to the idle condition.
Document Number: 710-10864-00_SCPx11x-DFTB3_1017qsg
2. If Termination is necessary on the receive lines, a built in
120 Ω resistor can be switched in using DIP Switch Position
6. In most cases, termination is not required. The default
setting is OFF (termination "out".)
a. Termination is used to match impedance of a node to the
impedance of the transmission line being used. Termination
increases load on drivers, increases installation complexity,
changes biasing requirements and makes system
modification more difficult. Generally, termination should
only be used for long distances. "If in doubt, leave it out."
8
Loop-back Test/Troubleshooting
Configure for RS-485 4-wire.
Jumper terminals B to D and C to E.
Connect a PC to the RS-232 port.
TD and RD LED's are ON when power is applied.
Using hyper terminal or similar program, connect to the
appropriate COM port. Turn off hyper terminal local echo.
Transmit data. The same data should be returned. When
data is sent and looped back, the TD and RD LED's blink
On and Off indicating data flow.
Recommended Accessories
12V DC, 6W, Int'l AC Input,
Stripped/Tinned
Power Supply
#SMI6-12-V-ST
10-30V DC, 2.5W
Power Supply
#MDR-40-24
DIN Rail Adapter Clips
#DRAD35 (pair)
1-888-948-2248 | Europe: +353 91 792444
advantech-bb.com
707 Dayton Road | PO Box 1040 | Ottawa, IL 61350
Phone: 815-433-5100 | Fax: 815-433-5109
www.advantech-bb.com | E-mail: support@advantech-bb.com

QUICK START

GUIDE
RS-232 to RS-422/485
Industrial Converters
SCP211-DFTB3, SCP211T-DFTB3 or SCP311T-DFTB3
Before you begin, be
sure you have the following:
+ SCPx11x-DFTB3 Converter
+ Quick Start Guide (included)
+ 10-30V DC, 2.5W Power Supply
(not included)
www.advantech-bb.com
Fast and easy on the web: