9
CHAPTER 3: Configuration and Installation
loop side of the Converter to the current-loop device interface. For best results,
these 4 wires should be in twisted pairs.
To install the Converter in an active current-loop environment, you will need a
DB25 cable with at least 4 conductors. These conductors should be wired to the
appropriate DB25 pins as shown in
Figure 3-2
. Since the end of this cable connects
to the Converter, its gender should be opposite to that of the Converter’s
connector. When you connect this cable to your current-loop device, be sure the
signal paths correspond to those shown.
The RS-232 side of the Converter is designed to plug directly into the serial port
of your RS-232 device. You may use a straight-through RS-232 cable for connection
as well. Be sure to set the Converter’s DCE/DTE switch according to the
instructions in
Section 3.1
.
Figure 3-2. Connection to an Active Current-Loop Interface.
3.2.2 RS-232
TO
P
ASSIVE
C
URRENT
L
OOP
R
UNNING
A
CTIVE
You may install the Converter into environments where an RS-232 device is
communicating with a passive current-loop device. In this case, you will need to
supply external DC power to the Converter on the current-loop interface side.
Figure 3-3
shows the appropriate pins/voltages for applying external DC power to
the Converter.
To install the Converter in a passive current-loop environment, you will need a
DB25 cable with at least 3 conductors plus shield. Wire the cable as shown in
Figure 3-3
, paying attention to jumpers and signal paths. Since this end of the cable
connects to the Converter, its gender should be
opposite
that of the Converter’s
connector. When you connect this cable to your current-loop device, be sure the
signal paths correspond to those shown.
The RS-232 side of the Converter is designed to plug directly into the serial port
of your RS-232 device. You may use a straight-through RS-232 cable for connection
25 (R+)
23 (R-)
14 (T+)
19 (T-)
(T+)
(T-)
(R+)
(R-)
CONVERTER
Current Loop
Side
RS-232 Side
Active Current
Loop Device
