Hello and welcome back to KEB America. Today I'm here to provide an introduction to the digital
data types used in fieldbus communication.
The basics of digital data types as a foundation for fieldbus communication
A bit is the most basic form of computing digital communication
and is crucial to understanding fieldbus communication. A bit is shortened from binary
digit and is simply a stored 1 or 0. A 1 typically refers to on, or true, or yes, while a 0
refers to off, or false, or no. From this very basic one or zero complex communication can be built.
From the foundation of the basic bit of a one or a zero we can then build upon that and group
them together to form larger data types. So we can see here the four bits. If we group them together
they are what's called a nibble. And then, while that is a rather uncommon term,
more commonly it may be known as a hex code so a hex is just simply four bits grouped together.
Now for the values of the bits on the hex codes with each bit being 0 or 1, and with 4 bits being
in the hex code we have 16 different unique combinations. So at the very basic, they could
all be zero, they could all be one, or for a little bit more complex example these two outside bits
could both be zero while the two inside bits are one so ultimately four bits one or zero each for
sixteen different unique combinations. So at the very basic if they're all zero. What's referred
to as the decimal value will also be zero and this column the hex value would also be zero.
So pretty basic all zeros. If all of the bits are 1. Your decimal value would be 15.
So a total value from 0 to 15 is 16 different combinations. And then your hex value would be
f. So, the hex value is a little bit different. Rather than being from 0 to 15
it goes from 0 to 9, and then A, B, C, D, E, F for 16 total different unique combinations.
So now that we've talked about the basic bit for a zero and one, and a hex which is four bits we
can then group those together into even larger data types for even more complex communication.
So if we look over here we have eight different boxes for a hex value.
If we group two of them together that's what's referred to as a byte,
a b-y-t-e, not a bit, and then if we group two bytes together, so four hexes, we have a word.
And then, not the most creatively named, but if we group two words together we get a
double word. So finally, we have 32 bits each, 16 bits each, 8 bits each, and 4 bits each.
So, now that we've talked about how many bits are in each different data type we can expand upon
the values to see what the various value ranges are. So for this one, let's look at a
byte. So in this one we have eight bits in each byte which all can again still be zero or one.
If all of them are zero, you still have a value of zero for your decimal, and zero for your hex.
If all of them are one, you then have 256 different combinations. So your final decimal value is 255.
So from 0 to 255, 256 combinations. And then finally, your hex values range from 00, to ff.
So now that we've looked at the different value combinations for the byte, those are then grouped
together for even larger words, and double words. So the word has 65,536 different combinations,
while the double word is over 4.2 billion. So these little 0s and 1s of the bits can be
combined together for very large data types for complex communication. If you'd like to learn more
about fieldbus communication or industrial automation, check us out at kebamerica.com