B&B Electronics 232CL9R User manual

232CL9R0812 1
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax [phone]
9-Pin RS-232 to
Current Loop Converter
Model 232CL9R
Documentation Number 232CL9R-0812
This product Designed and Manufactured
of domestic and imported parts by
International Headquarters
B&B Electronics Mfg. Co. Inc.
707 Dayton Road -- P.O. Box 1040 -- Ottawa, IL 61350 USA
Phone [phone] -- General Fax [phone]
Home Page: www.bb-elec.com
Sales e-mail: [e-mail] -- Fax [phone]
Technical Support e-mail: [e-mail] -- Fax [phone]

2 232CL9R0812
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax [phone]
The Model 232CL9R is a passive 9 pin RS-232 to current loop converter.
This converter requires a 12VDC-power supply at 100mA. Additional
resistors are supply for an active source.
To connect the converter to an existing current loop port, you must first
determine if the port is active or passive. For a port to be active, it must
have an internal power supply which provides the 20mA current for the
transmitter, receiver, or for both. This information should be available in
the instruction manual. If the instruction manual is not available the
simplest way to determine this is to break the loop (disconnect it) and see
if there is any DC voltage across the output or input pairs.
Current loop interfaces normally consist of four wires. They are usually
labeled T+, T-, R+, and R-. T+ and T- are the transmit plus and transmit
minus lines and data is output from that device on those lines. The R+
and R- lines are the receive plus and receive minus lines and data is input
into that device on these lines.
Interconnection of the two current loop devices is different depending on
whether your unit is active or passive. Connection to an active current
loop port is very simple. Your unit’s T+ and T- lines go to the B&B unit’s
R+ and R- lines, and your unit’s R+ and R- lines go to the B&B unit’s T+
and T- lines, as shown in figure 2.

232CL9R0812 3
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax [phone]
Figure 1.

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B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax [phone]
Connection to a passive current loop port requires a 12 VDC power
supply. Use the 470 ohm resistors inside of our converter to create a
20 ma current source, as shown in figure 3.

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B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax [phone]
Interconnection of two B&B current loop converters also requires the use
of a 12 VDC power supply since they are both passive ports.
See figure 4.