Rockwell-automation 1771-QB Linear Pos. Manual de usuario descargar pdf (Pagina 219)

Data Formats

Appendix H

H2

Following are two methods to get the negative of a number using the 2’s

complement method.

Bit Inversion Method

To get the 2’s complement of a number using the bit inversion method you must

invert each bit from right to left after the first 1.

Example: To represent -1524 (decimal) in 16-bit 2’s complement format, we

start with the binary equivalent of the positive of the number.

1524 (decimal) = 0000 0101 1111 0100 (Binary)

Next, we invert all the bits of the number from right to left starting with the bit

after the first 1 that we encounter.

-1524 (decimal) = 1111 1010 0000 1100

Subtraction Method

To get the 16-bit 2’s complement of a number using the subtraction method you

must subtract the number from 2

Thus to represent -1524 (decimal):

1 0000 0000 0000 0000

-0000 0101 1111 0100

____________________

1111 1010 0000 1100

Many of the words in the module’s data blocks use implied decimal points. This

means that, although the value you want to enter into a word may have a

fractional component, you only enter the digits, not the decimal point, when you

type it into the programmable controller data table.

Implied Decimal

1 2 ... 214 215 216 217 218 219 220 221 222 223 224 225 226

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Rockwell-automation 1771-QB Linear Pos. Manual de usuario Pagina 219