16
ASYNC 232
↔
422/485 CONVERTER
5.
Connect
the other pair of wires
to RCV+ and RCV- on the terminal block,
again making careful note of which color is positive, and which color is
negative.
NOTE
Positive and negative are relative terms and may not always have the
same relationship for all RS-422 or RS-485 devices (see the previous
note regarding “flipping the leads”).
Ultimately, you will want to construct a two-pair crossover cable that makes
a connection with the RS-485 device as shown below.
Converter
RS-485 Device
XMT+ ............................................................RCVA
XMT- .............................................................RCVB
G .....................To Shield (Optional)
G
RCV- .............................................................XMTB
RCV+ ............................................................XMTA
IMPORTANT!
If you are not using two IC476A-X-R2s back to back and the procedure on
the previous page produces garbage data (or none at all), flip the “A” and
“B” leads at one end of the 485 connection.
6.
If there is a shield around the twisted-pair cable, it may be connected to
“G” on the terminal block. To avoid ground loops, we recommend
connecting the shield at the computer end only.
A ground wire is not necessary
for proper operation of the Converter.
7.
When you finish connecting the wires to the terminal block, the assembly
should resemble the diagram at the top of the next page.
One pair
One pair
