The DRA-DCC-8 is a
microprocessor-based unit which
converts digital data into eight
continuous analog current loops.
The processor controls the digital
input, handles the active memory of
the unit and updates the current
outputs. For digital input range of
000 HEX to FFF HEX, the unit
provides two user selected output
current spans of either 4 to 20 mA
or 0 to 20 mA.
One parallel and two serial ports are
available. The parallel input port
receives an asynchronous 15 bit
bus composed of a 3 bit output
channel address and 12 bits of data
representing the output current
value. DRA-DCC-8 units can be
connected in parallel to the input
bus and selected by controlling the
Enable (E) input terminal. The unit’s
controller continuously scans the
input data field and compares it to
the previously stored data. When
new data is encountered, the old
data is replaced and the proper
output current is updated.
The DRA-DCC-8 provides both
RS-232C and RS-422 full duplex
serial communications ports. The
RS-422 serial communications port
enables use of up to eight
DRA-DCC-8 units in a multi-drop
configuration. A set of seven internal DIP switches enables
parameters such as baud rate, unit
identity code, digital input mode
(parallel or serial) and output current
span (4-20 mA or 0-20 mA) to be
set by the user.
