Signed-magnitude binary, Signedćmagnitude binary – Rockwell Automation 1771-IFE ANALOG INPUT MODULE User Manual
Page 69
D–2
Data Table Formats
Publication 1771Ć6.5.115 - February 1999
Table D.A BCD Representation
Place Value
2
3
(8)
2
2
(4)
2
1
(2)
2
0
(1)
Decimal
Equivalent
0
0
0
0
0
0
0
0
1
1
0
0
1
0
2
0
0
1
1
3
0
1
0
0
4
0
1
0
1
5
0
1
1
0
6
0
1
1
1
7
1
0
0
0
8
1
0
0
1
9
Signed–magnitude binary is a means of communicating numbers to
your processsor. It should be used with the PLC-2 family when
performing computations in the processor. It cannot be used to
manipulate binary 12-bit values or negative values.
Example: The following binary number is equal to decimal 22.
10110
2
= 22
10
The signed–magnitude method places an extra bit (sign bit) in the
left–most position and lets this bit determine whether the number is
positive or negative. The number is positive if the sign bit is 0 and
negative if the sign bit is 1. Using the signed magnitude method:
0 10110 = +22
1 10110 = –22
SignedĆmagnitude Binary