Rockwell Automation 1770 DH,DHII,DH485 CABLE - Manual (Page 115)

Constructing RS-232-C and
Longline Cables
Appendix A
A-3
If you are making connections directly between two Allen-Bradley interface
modules, you can often take advantage of a longline communication circuit that
lets you extend the link up to 7,000 feet (2135 meters). Table A.B lists the
possible longline connections and lists which cables you may use for the
connections.
Table A.B
Cables for longline connections.
To connect: to: use:
1771ĆKE, 1771ĆKF, or
1771ĆKG module
1771ĆKE, 1771ĆKF, or
1771ĆKG module
adapter cable wired according
toFigure A.14.
1773ĆKA or 1775ĆKA module adapter cable wired according to
Figure A.15.
1773ĆKA or 1775ĆKA
module
1773ĆKA or 1775ĆKA module adapter cable wired according to
Figure A.16.
To construct the adapter cables, use Belden 8723 cable which you can purchase
from Allen-Bradley by catalog number 1778-CR.
You can make the adapter cable any length up to 7,000 feet (2135 meters), but
the cable length limits the communication rate on the link. Table A.C shows the
maximum communication rate for a given length of cable.
Table A.C
Communication rates for longline connections.
Cable Length Maximum Communication Rate
up to 2,000 feet (610 meters) 19,200 bits/second
2,000 to 4,000 feet 610Ć1220 meters 9,600 bits/second
4,000 to 6,000 feet (1220Ć1830 meters) 4,800 bits/second
6,000 to 7,000 feet (1830Ć2135 meters) 2,400 bits/second
The illustrations on the following pages show the pin outs for connecting
various devices.
Longline Connections
(up to 7,000 Cable Feet)