join numeric with join numbers function

[yandub666]

Hi !  a small question from a guy that didnt use labview for a while !

i need to use the join number function to join two DBL number A and B to form a new number A.B, just like the join numbers function

in the example i would like the results after the join number function to be 1.5 

however i understand that the function merge bytes/words together and the result is far from what i expect ....  any ways to 

A and B are extracted from modbus READ register command and are unsigned 16 bit

seems easy enough but i need a good refreshment on how those bits, bytes and numeric works together..   doh !

thank for everyone involved, Kudos to all labview champions!

[GerdW]

Hi yan,

it seems you really need a refreshment on all those bits/bytes/numeric representations 😄

Typecasting floats (DBL) to U16 will probably never result in the desired value.

Why do you convert your U16 modbus values to DBL anyway? Stick with U16 and you will have no problems using JOIN or any other bit-banging function...

[yandub666]

then why do i get 65541 as the result?

[GerdW]

Hi yan,

because 1*2^16+5=65541.

Which result do you expect?

[P@Anand]

You mean 1 and 5 should give you 15?

[GerdW]

Hi yan,

if Anands idea might be your goal you should use some simple math instead: 1 * 10 + 5

[yandub666]

thats why i need the end results to be in DBL, caus i want 1.5 as the results

not 15

[GerdW]

Hi yan,

so the simple math changes to a + b/10 with a=1 and b=5. Where's the problem?

The problem seems so simple, but you can not provide any good information/description of your logic/task. What does the manual of your device say about those numbers?

[yandub666]

the two register i am reading from the modbus device gives me a ppm values of a gas detection system

A being before the comma

B being after the comma

in the format A.B ppm

to log the values red by the system i need to combine them together before and then log them, display them in a graphic..etc

[GerdW · Accepted solution]

Hi yan,

as your description still isn't clear in all details I provide two options, see which one fits your needs: