Double word hex string to number format problem

[Lucky-Luka]

Hi everyone
I need to make a VI that receives 2-byte hexadecimal values as ASCII strings from a CAN-USB interface. I do however have a problem with the format in which I receive the values. To get the exact value I should add 0 in the middle of the values when missing.
I give an example to explain better.
I get the string:
2 8 D5 0 0 0 0 B 5 70 <CR><LF> (value: 46448)
I'd like to interpret it as:
2 8 D5 0 0 0 0 B 05 70 <CR><LF> (value: 722288)
I'll give another example.
I get the string:
2 8 D5 0 0 0 0 B 4 5 <CR><LF> (value: 2885)
I'd like to interpret it as:
2 8 D5 0 0 0 0 B 04 05 <CR><LF> (value: 721925)
The maximum value I can read is 1000000 in any case.
Does anyone have an idea what algorithm I can use? Thank you!

p.s. there is an error: it's double word HEX: 4 bytes HEX not 2 bytes HEX

[billko]

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@Lucky-Luka wrote:

Hi everyone
I need to make a VI that receives 2-byte hexadecimal values as ASCII strings from a CAN-USB interface. I do however have a problem with the format in which I receive the values. To get the exact value I should add 0 in the middle of the values when missing.
I give an example to explain better.
I get the string:
2 8 D5 0 0 0 0 B 5 70 <CR><LF> (value: 46448)
I'd like to interpret it as:
2 8 D5 0 0 0 0 B 05 70 <CR><LF> (value: 722288)
I'll give another example.
I get the string:
2 8 D5 0 0 0 0 B 4 5 <CR><LF> (value: 2885)
I'd like to interpret it as:
2 8 D5 0 0 0 0 B 04 05 <CR><LF> (value: 721925)
The maximum value I can read is 1000000 in any case.
Does anyone have an idea what algorithm I can use? Thank you!

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This doesn't sound right to me.  Could you upload the documentation that describes the communications?  I mean, how are you supposed to determine if a zero is "missing"?

[altenbach]

With two bytes, you can only go up to 64k (2^16), not 100k.

Your examples are pure gibberish. Can you attach a VI that contains the exact received strings as e.g. diagram constant. What is the display style of these strings?

[GerdW]

Hi luka,

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@Lucky-Luka wrote:

Hi everyone
I need to make a VI that receives 2-byte hexadecimal values as ASCII strings from a CAN-USB interface.

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Please supply the dbc file that defines that message!

Why are there 10 values for a "2 byte value"?

[Lucky-Luka]

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@billko  ha scritto:

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I mean, how are you supposed to determine if a zero is "missing"?

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If I see just 1 character I have to add a zero at the beginning in order to have two characters.

After that I can remove the spaces and obtain the value of interest as in the attached VI.

[billko]

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@Lucky-Luka wrote:

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@billko  ha scritto:

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I mean, how are you supposed to determine if a zero is "missing"?

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If I see just 1 character I have to add a zero at the beginning in order to have two characters.

After that I can remove the spaces and obtain the value of interest as in the attached VI.

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I don't buy it.  I would be inclined more to think something is wrong with the way you are receiving the messages, and you think sometimes there is only one byte.  If a data type is specified in the output, you can bet that your output will always have the correct amount of bytes to represent that data type.

[rolfk]

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@Lucky-Luka wrote:

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@billko  ha scritto:

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I mean, how are you supposed to determine if a zero is "missing"?

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If I see just 1 character I have to add a zero at the beginning in order to have two characters.

After that I can remove the spaces and obtain the value of interest as in the attached VI.

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Nope! Just treat is as a space separated spreadsheet string of hex numbers “%x” converting it into a 1d array of unsigned 8bit integers!

Then Typecast or Unflatten the last 4 bytes into an uint32 number.