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DL-485OPB (RS-422/485 Optically Isolated Repeater
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The 485OPB can be used to optically isolate one piece of RS-485 equipment
from the rest of an RS-485 system, or one
local group of RS-485 equipment from another. It can also be used as an RS-485 repeater
to expand an existing RS-485 system to greater than the 32 node
limitation in the RS-485 Standard
All data lines as well as power and ground are isolated from one side of the 485OPB to
the other. The 485OPB uses
terminal blocks on each side of the device.
It supports Transmit Data (A) and (B), Receive Data (A) and (B), Protective
Ground, and Signal Ground.
Opreation
The 485OPB can operate in either two-wire half-duplex systems or in four-wire half-duplex or full-duplex systems
It can also operate as a four-wire to two-wire converter. By connecting one side of the 485OPB as a
two-wire device and one side as a four-wire device, equipment meant for a point-to-point RS-422 interface can be
connected directly to an RS-485 two-wire multi-drop system.
Proper operation of any RS-485 system requires the presence of a signal return path. The RS-485 Standard
recommends that a third wire be used for this. For safety, a 100 ohm resistor should be connected between frame
ground and signal ground at every drop point. For the transient suppression of the 485OPB to work properly, the
protective ground (PG) terminal must be tied to a good frame (chassis, green wire, or earth) ground. No wire type or
maximum run length is listed in the RS-485 Standard. However, the RS-422 Standard, which is very similar,
recommends number 24AWG twisted pair telephone cable with a shunt capacitance of 16 picofarads per foot and no
more than 1200 meters feet of distance.
Specification
Isolation:
2000 volts RMS for 1 min. optical
isolation of data lines and ground.
Surge Suppression:
6.5V working peak voltage, bidirectional
over voltage suppressor.
600W peak power dissipation.
3,000 pF maximum capacitance
Data Rates:
Up to 460.8K baud.
Temperature Rating:
0°C to +70°C
Power Requirements:
9-14V DC @ 60mA (idle state),
170mA (Full-duplex, 62 Ohm load)
Dimensions:
9.7L x 6.1W x 2.5H cm
Price: €109.00
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Contact:
DataLink Communications
Cloghaun, Kilchreest, Loughrea, Co. Galway, Ireland
Email: sales@datalinkcom.net Tel: +353-91-840838 Fax: +353-91-840839
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