Binary Number System

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The binary number system is used by all computers, PLC/PAC's and digital device.

The binary number system is a base-2 number system, therefore there are two valid digits:

0 and 1

One digit of binary is called a bit. Bits are used in groups to represent all other numbers. Bit grouping nomiclature is as follows:

The binary number system is used in computers and PLC/PAC's because it is easy to use a bit to represent voltage levels within the computer or PLC/PAC. A '0' = 0Vdc or Gnd and a '1' = +Vdc.

Each bit in the binary system as a position and a weight value assigned to it. Binary is a base-2 number system, therefore the weight of each bit is 2 raised to the power of the bit position.

Binary numbers can be written in two formats:

10110012  or  1011001b

The figure below depicts a 16-bit binary word showing terminology and the weight values of each bit location. Bit location zero is the bit on the far right and bit 15 is the bit on the far left.

Binary Term
                  diagram

Binary Weighting

Binary Weight

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John G. (Skip) Todora   ⇔   Late updated: November 11, 2009