BB-485LP9TB [ETC]

PORT PWR 9P/TERM BLK 485 CONV;
BB-485LP9TB
型号: BB-485LP9TB
厂家: ETC    ETC
描述:

PORT PWR 9P/TERM BLK 485 CONV

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中文:  中文翻译
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Document No. 485LP9TB0812 - pg. 1/2  
Port Powered RS-232 to RS-485 Converter  
Model 485LP9TB  
The 485LP9TB is a port-powered two-channel RS-232 to RS-485  
converter. It converts TD and RD RS-232 lines to balanced RS-485 signals.  
The unit can be powered from the RS-232 handshake lines, DTR and RTS. If  
port powering the unit, one of these handshake lines must be asserted (high) in  
order to power the unit (See Table 1). DTR must be asserted to receive data. The RS-485 driver is enabled when  
RTS is asserted and disabled when RTS is disasserted. The RS-485 receiver is disabled when the driver is  
enabled and is enabled when the driver is disabled.  
In order to maximize the amount of power available to the RS-485 driver, the RS-232 handshake lines  
are not looped back (tied together). As a result the following handshake lines will appear as disasserted (low):  
CTS, DCD, and DSR. Care should be taken to insure that any software being used doesn’t require any of these  
handshake lines be asserted. If existing software requires any of the handshake lines to be asserted, you can loop  
back the required handshake lines in your cable.  
Table 1  
RTS  
State  
Low  
DTR  
State  
Low  
Functions Possible  
(when port powering unit)  
none  
Low  
High  
High  
High  
Low  
High  
Receive  
Transmit  
Transmit  
* NOTE: Low = disasserted and High = asserted  
Connections  
A typical two wire RS-485 connected is shown in Figure 1. Regardless of the system, the 485LP9TB must  
be connected with the proper polarity. With no data is being sent and the driver enabled, the RS-232 line should  
be negative and the TD(A) should be negative with respect to TD(B).  
Proper operation of any RS-485 system requires the presence of a signal return path between the signal  
grounds of the equipment at each end of an interconnection. This circuit reference may be established by a third  
conductor connecting the common leads of devices, or it may be provided by connections in each equipment to  
an earth reference. When the circuit reference is provided by a third conductor, the connection between the signal  
grounds and the third conductor should contain some resistance (e.g. 100 ohms) to limit circulating currents when  
other ground connections are provided for safety.  
Biasing Resistors  
The biasing resistors for the RS-485 receiver are 4.7K Ohm resistors. These resistors are labeled R1 and  
R6 (See Figure 2). Refer to B&B Electronics RS-422/485 Application Note for further information on biasing.  
www.bb-elec.com orders@bb-elec.com support@bb-elec.com  
International Office: 707 Dayton Road PO Box 1040 Ottawa, IL 61350 USA 815-433-5100 Fax 433-5104  
European Office: Westlink Commercial Park Oranmore Co. Galway Ireland +353 91 792444 Fax +353 91 792445  
Document No. 485LP9TB0812 - pg. 2/2  
Figure 2  
Specifications  
Data Rate: 115.2K Baud max.  
Power:  
Port Powered from RTS and DTR.  
Note: If external power is required, use a source that can supply 12 to 16VDC at 40mA  
NOTE: When using an external supply, the supply should be connected only to specifically labeled power  
inputs (power jack, terminal block, etc.). Connecting an external power supply to the handshake lines may  
damage the unit. Contact technical support for more information on connecting an external power supply  
to the handshake lines.  
DECLARATION OF CONFORMITY  
Manufacturer’s Name:  
B&B Electronics Manufacturing Company  
Manufacturer’s Address:  
P.O. Box 1040  
707 Dayton Road  
Ottawa, IL 61350 USA  
Model Number:  
Description:  
485LP9TB  
9-Pin Port-Powered RS-485 Converter  
Light industrial ITE equipment  
89/336/EEC  
Type:  
Application of Council Directive:  
Standards:  
EN 50082-1 (IEC 801-2, IEC 801-3, IEC 801-4)  
EN 50081-1 (EN 55022, IEC 1000-4-2)  
EN 61000 (-4-2, -4-3, -4-4, -4-5, -4-6, -4-8, -4-11)  
ENV 50204  
EN 55024  
Robert M. Paratore, Director of Engineering  
www.bb-elec.com orders@bb-elec.com support@bb-elec.com  
International Office: 707 Dayton Road PO Box 1040 Ottawa, IL 61350 USA 815-433-5100 Fax 433-5104  
European Office: Westlink Commercial Park Oranmore Co. Galway Ireland +353 91 792444 Fax +353 91 792445  

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