Allen-Bradley A-B QUALITY DL20 Series User Manual page 76

Chapter 7
The Parallel Port
Using the Parallel Port
7–4
Data Line Values (Binary)
Table 7.B shows the value of the data lines using binary data inputs.
Table 7.B
Binary Data Line Values
Data Line
Data Line Value
D0 1
D1 2
D2 4
D3 8
D4 16
D5 32
D6 64
D7 128
D8 256
D9 512
The binary value of the data lines is the sum of the individual data lines: D0
+ D1 + D2 + D3 + D4 + D5 + D6 + D7 +D8 + D9 = Value
D0, D4 and D7 are at some voltage level, and the others are at ground level,
the value on the data lines is D0 + D4 + D7 = 1 +16 + 128 = 145.
Data Line Values (BCD)
In the BCD system, 4 bits represent one decimal digit. Table 7.C shows the
value of the data lines using BCD data inputs.
Table 7.C
BCD Data Line Values
Data Line
Data Line Value
D0 1
D1 2
D2 4
D3 8
D4 10
D5 20
D6 40
D7 80
D8 100
D9 200
Comments
Least Significant Bit
Most Significant Bit
Comments
(Range = 0 to 399)
Ones Digit (0-9) Ones Digit (0-9)
Tens Digit (0-9) Tens Digit (0-9)
Hundreds Digit (0-3) n s igi 3
.
For example: if