232CL24895 - pg. 1/1
B&B Electronics November 1995
Current Loop Converter
Model 232CL2
Document No. 232CL24895
This B&B converter inputs RS-232 Transmit Data (2) and outputs 20 ma current loop signals, T+ and T-.
The device also inputs current loop signals, R+ and R-, and outputs RS-232 Receive Data (3). High speed
optical isolators couple and isolate the TD and RD.
The following information will help you
make your interconnection:
1.
Connectors. The 232CL2 uses a male
DB25P connector for the RS-232
interface and a female DB25S connector
for the current loop interface.
2.
Power for the Converter. The Model
232CL2 is designed to use +/- 12 Volts
from pins 4, 5, 6, 8 and 20 to power the
RS-232 side of the unit. One of these pins
must be high and one must be low for the
unit to work. These lines will not be
necessary if you are converting in one
direction only, RS-232 to current loop,
and you do not need to convert from
current loop to RS-232.
NOTE: When
using an external supply, the supply
should be connected only to
specifically labeled power inputs
(power jack, terminal block, etc.).
Connecting an external power supply
to the handshake lines may damage
the unit. Contact technical support for
more information on connecting an
external power supply to the
handshake lines.
3.
Current Loop Power. The unit will
operate with active or passive current
loop ports, and no power is required on
the current loop side of the converter if
you port is active. If your current loop port
is passive (does not have power), an
external power supply of about 12 Volts
DC must be wired to pins 9 and 21. (See
figure). These pins are connected to
resistors inside the converter and are
used to create the 20 ma. current source.
Through-hole resistors R11 and R12
allow you to create a current loop other
than 20 ma.
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