Hexadecimal

Hexadecimal is another system used in PLCs. The hexadecimal
system has the following characteristics:

16 digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F

Base 16

Weights Powers of base 16 (1, 16, 256, 4096 ...)

The ten digits of the decimal system are used for the first ten
digits of the hexadecimal system. The first six letters of the
alphabet are used for the remaining six digits.

A = 10 D = 13
B = 11 E = 14
C = 12 F = 15

The hexadecimal system is used in PLCs because it allows the
status of a large number of binary bits to be represented in a
small space such as on a computer screen or programming
device display. Each hexadecimal digit represents the exact
status of four binary bits. To convert a decimal number to a
hexadecimal number the decimal number is divided by the base
of 16.
To convert decimal 28, for example, to hexadecimal:

1r 12
16)-----
28

Decimal 28 divided by 16 is 1 with a remainder of 12. Twelve is
equivalent to C in hexadecimal. The hexadecimal equivalent of
decimal 28 is 1C.

The decimal value of a hexadecimal number is obtained by
multiplying the individual hexadecimal digits by the base 16
weight and then adding the results. In the following example
the hexadecimal number 2B is converted to its decimal
equivalent of 43.

160 = 1
161 = 16
B = 11