Digital Data Stored In Bits, Bytes, Words And More - Siemens SIMATIC S7-1200 Getting Started

Quick review
1.1 Basic information about how the CPU works
1.1.3

Digital data stored in bits, bytes, words and more

The CPU organizes bits of data into groups. A group of 8 bits ① is called a byte ②.
A group of 2 bytes is called a "word". A group of 4 bytes is called a "double word".
You use the binary number system (base 2) for counting the numbers. A word can
represent an integer number from -32768 to +32767. The bit with the value 2
denote a negative number (when position 2
Note
The CPU also supports a grouping of 8 bytes that form a "long real" data type (LReal) for
storing very large or very precise values. The range for the LReal is: +/-2.23 x 10
1.79 x 10
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The smallest unit of information in a digital system is known as
a "bit" (for "binary digit"). A bit stores one of two possible
states, either a "0" (false or not true) or "1" (true).
A light switch is an example of a "binary" system with only two
states. The light switch determines either a "light on" or a "light off"
state, and this "value" can be stored in one bit. The digital value of
the light switch answers the question: "Is the light on?" If the light is
switched on ("true"), then the value is 1. If the light is switched off
("false"), then the value is 0.
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Each bit in the group is defined exactly by a separate
position with its own address. Each bit has a byte address
and bit addresses 0 to 7.
has the value "1" the number is negative).
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③ Word
② Byte
① Bit
is used to
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Getting started with S7-1200
Getting Started, 11/2009, A5E02486791-01
to +/-
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