Rockwell Automation 1746-FIO4V SLC 500 Fast Analog I/O/ User Manual - Manual (Page 83)

83 Publication 1746-UM009B-EN-P - September 2007
Appendix
B
2’s-complement Binary Numbers
Use 2’s-complement Binary
Numbers The SLC 500 processor stores data as 16-bit binary numbers. The
processor uses 2’s-complement binary format when making
mathematical computations and when storing analog values in the I/O
image table.
As indicated in the figure on next page, the equivalent decimal value
of the 2’s-complement binary number is the sum of corresponding
position values. The corresponding position value is equal to 2 raised
to the power designated by the position, beginning at the right with 2
0
and ending at the left with 2
15
. The bit value in each position can be 0
or 1, where 0 excludes the corresponding position value from the sum
and 1 includes it.