How to get the hexadecimal value of a channel of a message on CAN bus using channel API only ?

[Lab V]

Hi,

I'm trying to read the hex value of a channel. The channel belongs to a message on the CAN bus. I'm supposed to use only channel API.

In the VI, I'm using an index array to extract the 5th channel of a message. I need to get hex value of this particular channel on the CAN bus .

[altenbach]

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@Lab V wrote:

"I'm supposed to use only channel API."

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What does that statement mean, exactly???

[mikeporter]

An important point: You need to remember that in the computer a number of just a pattern of binary bits that we humans tell the computer to interpret for us in a few set ways. LV can display a number in a variety of ways depending on the radix of the indicator or control holding it. However, this is only a display issue the underlying bit pattern that is the numbers real value remains unchanged.

So if this "conversion" is required for display only, wire the data value up to a numeric indicator, set the indicator's radix to hex, and you're done.

If you need to output this hex representation of the number to say a text file, either Format into String or Number to Hexidecimal String can make the conversion for you.

Mike..

[JB]

Hi Christian,

There are two sets of VIs for the CAN bus : Frame API and Channel API. Read this document for more details.

Wish you a nice day

[Lab V]

I'm supposed to use only channel API means, I've have 2 NI CAN ports. I'm using channel API for one of the ports and frame API for the other. This issue is with channel API. I tried to change the radix of the 'Value' to hex, but it doesn't work. 

-Arun

[JB]

What type of value are you expecting : float or integer ? CAN Read.vi returns an array of DBL and it is obviously not possible to change the display mode of a float to HEX.

If the expected value is an integer :
1. Change the representation of your indicator to the appropriate type --> right-click on the indicator >> Representation
2. Make the radix visible --> right-click on the indicator (Front panel) >> Visible Items >> Radix
3. Change the display mode to hexadecimal --> right-click on the indicator >> Properties >> Format and Precision >> Hexadecimal
4. (Insert the appropriate conversion function between the index array and the indicator to avoid the coercion dot)

If the expected value is a float, then it makes no sense to display it in hex !

[mikeporter]

Ok, if the value you are wanting to convert is essentially an integer that is being represented as a float, first convert the number into an integer datatype using something like the To Unsigned Long Integer function and then do the hex conversion. If the number coming back is a non-integer what exactly are you looking for in a hex representation? Are you wanting to see the IEEE floating-point representation of the value?

Mike..