Hi all

 

 

Im currently studying for an HND in mechatronics engineering. Working on an asignments for PLC's

 

Im stuck on a part of one question!

 

Its "what can BCD numbers do that pure Binary or Hexadecimal numbers cannot?"

 

Im struggling like hell to find an answer on the net, can anyone help?

Wiki's article on Binary Coded Decimal offers up several answers to this question. I don't think there is one thing in particular that BCD does that the others do not that fits this question precisely. The few things that are mentioned however do serve as the main factors for choosing to use this numerical representation for computational purposes. I'm particularly fond of its uses in representing certain values more precisely than other similar methods of numerical representation.

 

Someone with more experience might help so . . . .

Hi all

 

 

Im currently studying for an HND in mechatronics engineering. Working on an asignments for PLC's

 

Im stuck on a part of one question!

 

Its "what can BCD numbers do that pure Binary or Hexadecimal numbers cannot?"

 

Im struggling like hell to find an answer on the net, can anyone help?

 

In the sense that any number system can be used for mathematical operations given suitable hardware and software, one answer is "nothing" (IMO). There can be a benefit in that it can be a help to a human wishing to convert the numbers in this system straight into decimal. And it is easy for a human to convert a decimal number into BCD. http://en.wikipedia.org/wiki/Binary-coded_decimal

thatnsk for the reply ill take a look!

I would guess, although I don't specifically know, the question is looking for this:

 

http://speleotrove.com/decimal/decifaq1.html#inexact

 

It can accurately represent decimal fractions where binary and hex cannot.

I would guess, although I don't specifically know, the question is looking for this:

 

http://speleotrove.com/decimal/decifaq1.html#inexact

 

It can accurately represent decimal fractions where binary and hex cannot.

 

Yes - I had overlooked that.

that seems to refre to binary floating point not binary coded decimal!

.2 is irrational in binary but rational in BCD. This means that computations that require precise decimal representation become less precise with the use of binary as rounding is involved. This extends to floating point mathematics under each respective representation!

 

"precise decimal representation" == common base 10 decimal numbers ie. .2

is this the same for hex as well?

.2 is irrational in binary but rational in BCD. This means that computations that require precise decimal representation become less precise with the use of binary as rounding is involved. This extends to floating point mathematics under each respective representation!

 

"precise decimal representation" == common base 10 decimal numbers ie. .2

 

yeah... that

 

is this the same for hex as well?

 

hex and any base not a multiple of 10

Edited October 28, 201114 yr by Iggy

sorry could someone put this in slightly more simple terms, its friday night im on late shift til 11 and the brain is fried!

If it is irrational in binary how would it be rational in hex? Hex codes for binary so if it requires an infinite set of binary decimal places than it will require an infinite set of hex decimal places to code for it . .. . .

sorry could someone put this in slightly more simple terms, its friday night im on late shift til 11 and the brain is fried!

the answer to this...

 

Its "what can BCD numbers do that pure Binary or Hexadecimal numbers cannot?"

would seem to be that BCD can accurately represent decimal fractions (without rounding) while binary and hex cannot. Do you understand what that means?

yeah thanks! feeling a bit thick tonight! its been a long week, two huge assignments due in Monday as well as work, kids, wife etc! thanks all for the help!

no trouble. Good luck.