PARAMETER 09:
Serial Baud
SERIAL BAUD IS 1200 MM/DD/YY HH:MM:SS
Background:
PARAMETER 11
specifies the number of
Serial Data Bits,
either 7 or 8,
that will be used to construct each character of data sent from the CP-220A
to the
Automation System's
computer. This data typically consists of
hexadecimal characters (e.g., 1234 E2; see
Appendix B
), which are each
made up of specific numbers of
0s
and
1s
– called
bits
or
binary digits
(see
Appendix A
). To represent the data, these bits are arranged to conform to
the
ASCII
(American Standard Code for Information Interchange)
Character Set,
a standard used throughout the computer industry.
The following table provides the
ASCII
equivalents of each of the 16
hexadecimal characters that may comprise the messages transferred
between the CP-220A and the computer.
THE 16 HEXADECIMAL CHARACTERS AND THE ASCII CODES
REPRESENTING THEM
CHARACTER ASCII EQUIVALENT CHARACTER
ASCII EQUIVALENT
0
011 0000
8
011 1000
1
011 0001
9
011 1001
2
011 0010
A
100 0001
3
011 0011
B
100 0010
4
011 0100
C
100 0011
5
011 0101
D
100 0100
6 011
0110
E 100
0101
7
011 0111
F
100 0110
Notice that each of the characters requires just 7 bits, although the
CP-220A (and any computer system) sends data in groups of 8 bits, called
bytes
(see
Appendix A
). The available "bit position" can simply be replaced
with a 0, or it can be used to send an
error checking
or
parity
bit – used for
checking data integrity. The details of how parity works are beyond the
scope of this manual, but suffice it to say that both the
Automation System's
computer and the CP-220A must agree on the type of parity bit sent, or
whether it is sent at all
.
CP-220A Central Station Receiver
Section 2: Programming the CP-220A Page 2-79
Hook-Up and Installation Manual