binary

[smercurio_fc]

A CANbus data frame has a data field that is up to 8 bytes. So, I'm guessing he probably just needs to send the DBL in IEEE 754 format. The specs for the instrument he's talking to should provide this information, though.

[Coq_Rouge]

I took a quick look on the NI can buss VIs. It looks like data is transferred as U8 arrays. I made a quick example on how to convert between some labview types. Then using the cast function you may cast almost cast everything to anything.

I have also noticed that most of the replays was not so helpful as you hoped. The reasons for this is the question you asked. It was not very detailed or specific. Just remember it to the next time you asks a question:smileywink:

Here is some useful tips for the Labview beginner (we have all been there some time)

1)Then starting a new Labview session enable context help (Ctrl+h). Do not be afraid to use the detailed help option

2)Then stuck, go to help in the toolbar then select find examples

Message Edited by Coq rouge on 05-05-2009 11:19 AM

[aznw82]

tried to use your vi; dont think its working correctly. i had inputed number -1.5 but, didn't see the binary output.

i want to see if i'm doing it correctly. if i input -1.5, the binary output will be 10111111. is that right??

[Coq_Rouge]

I did not know that you plan to measure negative voltage. But anyway replace all U16 conversion/casting with I16. Here is a tip. You may change the display format of any numeric control/indicator/constant by right cliking on it and then selecting properties->display format. Integers can be set to binary or hex  

[aznw82]

change the U16 to I16, and got this 1000000 for -1.5? does that seems right? 

[smercurio_fc]

You are assuming that's what the instrument requires.

To OP: Instead of guessing around with what you want and what you need, please provide a link to the documentation for the specific instrument/component that you're talking to, or upload the PDF for it.

[aznw82]

this is what i got, view attached

[altenbach]

---

aznw82 wrote:
this is what i got, view attached

---

This does not explain how a floating point number is scaled into 16 bits.

Do you have any other documentation (e.g. Figure 12, page 24[3])?

(This page also does not look very professional. A rate with units ms is probably incorrect. ;))

Do you have a working instruments where you can look at readings and the corresponding message? If so, please post some messages.

[aznw82]

i dont have many information for this design. the rest is just like this, but in like current & software version input.

so, not much details. i dont even have figure 12, page 24

[smercurio_fc]

That's just one page. Where's the rest of it? As it is, there's no way to tell how the 16 bits are supposed to relate to a voltage or temperature. Since it's only 16 bits it's probably a floating point number that's scaled by a factor of 10^n, though what the n is in this case is anybody's guess.

Side-note. I find it amusing how the table shows MSB for both the first column and last column. Yeah, that's real clear.