12
RS-232
↔
CURRENT LOOP INTERFACE CONVERTER
(6) Test results:
(a) If the TX LED on the CL050 is
off, the other device is active.
(b) If the TX LED on the CL050
lights continuously, there is no current
in the loop. Therefore, the other
current-loop device is passive.
(c) If the TX LED flashes, the
current loop is sending data. This
indicates that the other device is active.
(7) Unplug the CL050 from the AC
outlet and remove the R- to R- and R+
to R+ wires.
4.1.2 V
OLTMETER
T
EST
Attach the voltmeter to the two
Transmit lines (T+ and T-) of a current
loop device (not the CL050). If the
voltmeter reads voltage, the device is
active. If no voltage registers, the
device is passive.
4.2 Connecting the Current Loop
Wires to the CL050A
When you attach current loop wires to
the CL050, the unit should not be
connected to an AC outlet. Unless very
fine stranded-wire cable is used, wire
tinning is not required. Just insert the
wire into the receptacle and tighten
the screw. The wire will be firmly
gripped by the terminal. Table 1
details how the current loop should be
connected to the CL050. Refer also to
Figures 4-3 through 4-7 on pages 8, 9,
and 10.
4.2.1 4-W
IRE
C
URRENT
L
OOP
Regardless of whether the CL050 is
active or passive, attach the current
loop wires as indicated in Table 1 and
as shown in Figures 4-3 or 4-4.
Terminals
1 (T+)
2 (T-)
3 (R+)
4 (R-)
4-Wire Full-Duplex
+ Receive
- Receive
+ Transmit
- Transmit
2-Wire Half-Duplex
+ Loop
Jumper to
Jumper to
- Loop
Passive
3 (R+)
2 (T-)
2-Wire Half-Duplex
No
+ Loop
- Loop
No
Active
Connection
Connection
Table 1. Current Loop Cable Connections.
