Ohaus RS422 Interface Option Kit Manual multi User Manual
Page 5
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RS485 / RS422 Option Kit EN-3
• The RS485 / RS422 option may be configured for either duplex (4-wire) or half
duplex (2-wire) operating mode. Jumper W1 must be removed for duplex mode
and installed for half duplex mode.
Figure 2.3 Duplex Figure 2.4 Half Duplex
• A ground connection is provided on connector J2 for systems that require it.
•
A 120 Ohm termination resistance is provided by installing a jumper on connector
W2 of the RS485 / RS422 pc board. When W2 is shorted, the termination
resistance is placed between the RXD + and RXD - lines.
•
For more information about RS485 installations, refer to the document TSB-89-A
Application Guidelines for TIA/EIA-485-A
, published by the
Telecommunications
Industry Association.
.
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