Panasonic FP3 Technical Manual page 75

battery low:
baud:
BCC:
BCD:
binary:
Binary Coded Decimal (BCD):
A condition that exists when the backup battery voltage drops low enough to
require battery replacement. For FP3 CPU, FP10S CPU, S-RAM and
S-RAM/Flash-EEPROM type IC cards, the ERROR LED turns ON.
Formally defined as the shortest pulse width in data communication.
However, usually used to refer to the number of binary bits transmitted per
second (bps) during serial data communication.
See Block Check Code
See Binary Coded Decimal
In general, programmable controllers work with binary numbers in one form or
another to represent various codes or quantities. The binary number system uses
the number 2 as the base and the only allowable symbols are "0" and "1." There
are no 2s, 3s, etc. Each digit of binary is called as "bit." "Bit" means "binary
digit." A group of 8 bits is called a "byte" and a group of 16 bits (two bytes) is
called a "word."
Most significant bit
(MSB)
Bit position
15 14 13
Binary data
0 0 0
The binary number "0000000000101011" is expressed in decimal as follows:
1 × 2 + 1 × 2 + 0 × 2 + 1 × 2
0 1 2
= 1 + 2 + 0 + 8 + 0 + 32 + ..... + 0
= 43
One of the codes expressed in binary. BCD is a binary code in which each
decimal digit from 0 to 9 is represented by four binary digits (bits). The four
positions have a weighted value of 1, 2, 4, and 8, respectively, starting with the
least significant bit. A thumbwheel switch is specified as a BCD device, and
when connected to a programmable controller, each decimal digit requires four
inputs.
BCD is usually expressed grouping four bits as one digit in the same way as the
hexadecimal constant H. When BCD is grouped in four bit units, the BCD is
expressed by adding the prefix H to the data. Since the weight of each BCD
H code is same as that of decimals, be sure to pay attention not to be
confused with hexadecimal numbers when BCD H code is handled.
Example: When K1993 (decimal) is expressed in BCD.
K 1
Decimal
BCD code
0 0 0 1 1 0 0 1
H 1
BCD H code
10
Least significant bit
12 11 10 9 8 7 6 5 4
0 0 0 0 0 0 0 1 0
byte byte
word
+ 0 × 2 + 1 × 2 + ..... + 0 × 2
3 4 5
9 9 3
1 0 0 1 0 0 1 1
9 9 3
1
×9 = 90
10
2
×9 = 900
10
3 ×1 = 1000
6-3. Terminology
(LSB)
3 2 1 0
1 0 1 1
15
0 ×3 = 3
10
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