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automation:topics:bit_byte [2025/12/08 13:39] – vamsanautomation:topics:bit_byte [2025/12/08 14:01] (current) – vamsan
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 A byte is a variable type consisting of 8 bits. The value stored in it must be somewhere between 0 and 255, depending on the bit positions. The example below may help you understand this a little: A byte is a variable type consisting of 8 bits. The value stored in it must be somewhere between 0 and 255, depending on the bit positions. The example below may help you understand this a little:
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 +{{:automation:topics:byte_pos_en.png|}}
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 +Let's take the bit sequence //"01010110"// as an example, which fills the above byte. The bits of a byte are always numbered from right to left; position 0 is always on the right. Each position corresponds to a given power of the binary number system; position 4 corresponds to 24 = 16. If there is a 0 in this position in the example, then it does not //"count"//; if there is a one, then its value "counts", and as can be seen in the rows marked in green, the sum of the //"counting"// rows gives the current decimal value of the byte, 86. That is, **2#**01010110 = 86.
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 +Therefore, the byte reaches its maximum value when all bits are set to 1. It can be calculated that **2#**11111111 = 255. The byte data type holds values between 0 and 255.
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 +In computing, in addition to the base-10 number system, we also use the binary and base-16 number systems. The values ​​described in it are called hexadecimal numbers and are denoted by the prefix “**16#**” or sometimes “**hex#**”. Sometimes the hexadecimal number system is simply the hash, like this: “#ABCD”. The hexadecimal number system changes order of magnitude at 16, meaning that a position can contain a value between 0 and 15. This can be very confusing in the base 10 number system, so the two-digit positions are denoted by letters: \\ 
 + \\ 
 +10 = 16#A \\ 
 +11 = 16#B \\ 
 +12 = 16#C \\ 
 +13 = 16#D \\ 
 +14 = 16#E \\ 
 +15 = 16#F \\ 
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 +If a byte reaches its maximum value, meaning every bit is set to “1”, then: **2#**11111111 = 255 = **16#**FF
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 +If we calculate: F, i.e., “15” * 16 + “15” = 255
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 +In some ways, this can make our lives easier, because if we see a value of “**16#**FF” somewhere, or a longer series of these, for example “**16#**FFFF_FFFF”, then we can suspect that we have reached the maximum value of one of the variable types.
 +I would also like to mention the 8-bit, i.e., octal number system, it sometimes still occurs here and there, for example, in the case of numerical symbols, but only rarely, we don’t really use it.
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