Rockwell Automation 1770-KF2 Data Highway or Highway Plus Interface Module User Manual - Manual (Page 140)

Data Encoding and Addressing
Chapter 6
6-3
Binary Coded Decimal
PC data is often represented in binary coded decimal (BCD) form. In this
system, each group of four bits in a PC word represents one decimal
number between 0 and 9. In this way, each 16-bit word can represent a
BCD value between 0 and 9,999. Figure 6.2 shows the BCD
representation of the decimal number 239.
Figure 6.2
BCD Representation of Decimal 239
0 0 1 0 0 0 1 1 1 0 0 1
2 3 9
10241
0 x 2 3 = 0
0 x 2 2 = 0
1 x 2 1 = 2
0 x 2 0 = 0
0 x 2 3 = 0
0 x 2 2 = 0
1 x 2 1 = 2
1 x 2 0 = 1
1 x 2 3 = 8
0 x 2 2 = 0
0 x 2 1 = 0
1 x 2 0 = 1
2
3
9
10