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FEATURES
• Interconnect a digital 20/30/60-mA
unipolar Current Loop interface to
an RS-232 interface.
• Units available for active or passive
devices or passive-only devices.
• AC powered or interface powered.
• 220-VAC version of the active/passive
model is available.
• Switches control duplex, loop current,
and operation as either DTE or DCE
devices.
We have the ideal Current Loop solutions
for your point-to-point configuration!
OVERVIEW
The RS-232
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Current Loop Interface Converters are bidirec-
tional, self-contained units that enable you to interconnect a
digital 20/30/60-mA unipolar Current Loop interface to an
RS-232 interface. The converters cannot be used with an
analog Current Loop (4 to 20 mA) or bipolar Current Loop.
AC-Powered Active/Passive and Passive-Only
Converters
These Active/Passive RS-232
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Current Loop Interface
Converters (CL050A-R3, CL050A-E, and CL050-C) use AC power
and act either as active or passive devices on the Current Loop.
As active devices, these converters supply 20-, 30-, or 60-mA
loop current at 18 VDC for operation. As passive devices, the
converters will not supply loop current, but will operate with
20-, 30-, or 60-mA unipolar current at up to 30 VDC.
In contrast, the CL051A RS-232
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Current Loop Interface
Converter operates in passive mode only. It will operate with
60-mA unipolar current at 65 to 130 VDC.
Switch selections enable you to choose half- or full duplex
operation; loop current at 20, 30, or 60 mA; and configuring
the converters as either DTE (data terminal equipment) or DCE
(data communications equipment). Two LEDs monitor data
flow.
RS-232
↔
Current Loop
Interface Converter
(CL050A-R3)
5/16/2007
#17068
724-746-5500
blackbox.com
Current Loop
device
Device using
RS-232 interface
Current Loop was designed to transfer data in a noisy
environment with as much integrity as possible. All featured
interface converters include optical isolators in both the
transmit and receive loops to keep out electrical interference.
Note that the maximum calculated distance that any of
these converters or adapters can be placed from other devices
on the Current Loop is based on using 24 AWG and the lowest
data rate.
Technically Speaking
Interface-Powered Passive-Only Converters
For full duplex conversion of RS-232 async data to unipolar
Current Loop, choose an interface-powered converter (CL412A-
M, CL412A-F).
These units operate as passive devices only, and they must
connect to the active Current Loop. They derive their power
from the RS-232 device, which must provide 12 VDC on pins
6 or 20.
The converters are DTE/DCE selectable. Just flip a switch
on the side of the units to configure them to operate as either
data terminal or data communications equipment.