Rockwell Automation 5370-CVIM2 Module - Manual (Page 367)

5 Chapter Chapter 7
Inspection Tools
7–129
In this example formula, the decimal value 87
10
is bit–xored with the
decimal value 119
10,
which produces a result of 32
10
. The whole expression
is then modified by the “ bnot ” operator, the effect of which is to invert all bit
positions in a 32–bit version of the decimal 32
10
, changing it to a 32–bit
“1’s” complement result, as follows:
87
10
= 1010111
2
119
10
= 1110111
2
0100000
2
= 32
10
XOR
1111 1111 1111 1111 1111 1111 1101 1111
2
= 4294967263
10
BNOT
↓
0000 0000 0000 0000 0000 0000 0010 0000
2
= 32
10
However, since the 32–bit number resulting from the “ bnot ” operation is too
large, because of internal restrictions, that number can be “masked” down to
a more useful size by bit–anding it with an 8–bit mask of “1’s” (that is,
255
10
). The complete example formula would then appear as follows:
(bnot87bxor119)band255
This will yield a value of 223
10
, as shown below:
1111 1111 1111 1111 1111 1111 1101 1111
2
= 4294967263
10
0000 0000 0000 0000 0000 0000 1111 1111
2
= 255
10
0000 0000 0000 0000 0000 0000 1101 1111
2
= 223
10
bor –– The “ bor ” (bit or) logic operator is inserted between two expressions
(such as inspection results values) in a formula. The values of the
expressions (“inputs”) on both sides of the “
bor ” operator are converted to
binary equivalents and are “ored” at the binary level. The binary result of the
logic operation (“output”) is then converted back to decimal form.
In a simple example, two values are “bit–ored,” as follows:
87bor119
In this example, the ASCII value of the uppercase character “W” (87
10
) is
bit–ored with the ASCII value of the lowercase “w” (119
10
). The effect is to
convert the uppercase “W” to lowercase “w” by changing bit 5 to 1, as
follows:
87
10
= 1010111
2
119
10
= 1110111
2
1110111
2
= 119
10
OR
bxor –– The “ bxor ” (bit “exclusive” or) logic operator is inserted between
two expressions (such as inspection results values) in a formula. The values
of the expressions (“inputs”) on both sides of the “
bxor ” operator are
converted to binary equivalents and are “xored” at the binary level. The