Warner Electric CBC-1000 - Manual (Page 25)

Serial Interface
Two types of commands are available, LOCAL and
GLOBAL. LOCAL commands affect only the unit
that is currently addressed. GLOBAL commands on
the other hand affect all units regardless of address.
In this way it is possible to command many units to
begin control at the same point in time. The table
below lists the LOCAL and GLOBAL commands
that are supported.
Formats and Protocol
Character Format
The serial interface sends and receives information
by characters consisting of 10 bits. The
RS-422A/485 interface requires a 0.2V minimum
differential across + and - terminals. A logic high
(mark) is a positive differential and a logic low
(space) is a negative differential. ( Connection to
EIA-422/485 equipment that uses the opposite
polarity requires swapping the + and - connections
at the other equipment.)
The character format is as follows:
• Start bit (“low”) logic level)
• ASCII data (7 bits), least to most significant
• Parity bit (programmable)
• Stop bit (“high” logic level”)
Control
LOCAL GLOBAL Comments
Command
Output
(ESC) LO (ESC) GO
Simulates Output
Control Control Input
Batch
(ESC) LB (ESC) GB
Resets Batch
Reset to Zero
Counter
(ESC) LR (ESC) GR
Reset Counter
Reset to Zero
23 Warner Electric • 800-825-9050 P-275 • 819-0496
Parity Bit (see note)
The parity bit is programmable as “Odd”, “Even”, or
“No” parity. Odd and Even parity force the total
number of data bits to be even or odd for data that
is transmitted by the CBC-1000 control. Incoming
parity is always compared to the calculated parity.
Characters with parity errors are discarded. If No
parity is selected incoming parity is ignored.
Characters are transmitted with Odd or Even parity
as selected on line 24 of the program table. If No
parity is selected then “high” bit is added as an
extra Stop bit.
Baud Rate (see note)
Select the baud rate to match the device
communicating with the control. You may select:
300, 600, 1200, or 2400 baud on line 23 of the
program table. Gaud rate is common to both
transmitter and receiver.
Line Format
The CBC-1000 control transmits only complete
lines. The driver is turned off when not transmitting
causing the bus to enter a “float” state. Ignore data
on the bus during this “float” time. Unless otherwise
commanded, the CBC-1000 control continuously
transmits the Count Value. The line format is as
follows:
• a carriage return at the beginning of a line
• a prefix indicating RUN, SETUP, or
PROGRAM
• a unique line mnemonic
• a five digit data field with decimal point
• a carriage return at the end of the line
Note: To make changes in Parity or Baud Rate
power must first be removed then reapplied after
program changes to either are made. Both Parity
and Baud Rate are initialized when the control
“powers up”.
LOCAL and GLOBAL COMMANDS
HIGH
LOW
S D0 D1 D2 D3 D4 D5 D6 P S
ʻ
(sp) (sp) (sp) (cr) (cr) R
:
C o
.
1 2 3
.
4 5 6