Warner Electric CBC-1000 - Manual (Page 22)

20 Warner Electric • 800-825-9050 P-275 • 819-0496
Serial Interface
Overview
The CBC-1000 is equipped with an RS-422A/485 Serial Interface for remote data collection,
programming and networking applications. Front panel keyboard and some external control inputs
are supported. Additionally, facilities are provided for individual (local) and group (global) control of
single and multiple unit configurations respectively in a bus oriented system. Knowledge of serial
communications and the ASCII data format is required by the user who wishes to use the remote
capabilities or to integrate the control into a larger system.
Two applications will be discussed. The first consists of a single CBC-1000 and a display terminal. It
explains the use of the serial commands that mimic the keyboard operation and some control
inputs. An application of multiple units under the control of a host computer will also be discussed.
RS-232 to
RS-422/485
converter
RS-232 to
RS-422/485
converter
RXD
RXD RXD
RXD
COM
COM
COM
COM
TXD
TXD
TXD
TXD
—
—
—
—
+
+
+
+
RXD
—
RXD
+
TXD
—
TXD
+
COM
1 2 3 4 8
CBC-1000
CBC-1000 CBC-1000
RXD
—
RXD
+
TXD
—
TXD
+
COM BLDG GND
RXD
—
RXD
+
TXD
—
TXD
+
COM BLDG GND
Bldg Gnd
Bldg Gnd
COMPUTER
T
Single Unit Wiring
Multiple Unit Wiring
Termination
The RS-422A/485 receivers require termination to
minimize the effects of noise while the bus is not
being driven. The CBC-1000 incorporates the
terminations internally (as shown). When
connection is made to an RS-422/485 device other
than the CBC-1000, the receiver should be
terminated as shown.
TXD +
from
CBC-1000
TXD —
COM
To
Receiver
+5V
(2)
10 kΩ max. to
100 Ω min.