20
LD485A-HS and LD485A-HS Opto-Isolated
Figure 7
shows a typical multipoint, 4-wire, full- or half-duplex connection.
Figure 8 shows a typical multipoint, 2-wire, half-duplex connection. In the
multipoint applications depicted in
Figures 7
and
8
, the devices at the
extreme opposite ends of the installation are terminated by setting switch S2
to the TERM position. These devices are the two devices that have the greatest
cable length between them, not necessarily the devices that are physically
located the farthest apart. (See
Figures 7
and
8
.) A resistor shown in the
circuit indicates that the termination resistor has been selected via switch S2.
Note that although
Figures 7
and
8
show only four LD485A-HS devices
networked together, up to 64 units can be connected in the manner shown
in
Figure 7
, and up to 32 units as shown in
Figure 8
.