Our measuring instrument returns its data in three 8-bit bytes. We
are trying to log this data in a nice format to a log file. Currently
we have the logging, but translating the data to the format used on
the display of the actual measuring instrument is turning out to be
amazingly difficult in LabView.
Here is the short description of the problem: We need to:
* Translate hex values of 8-bit bytes into string literals.
> (For example, 52 -> "52", and F7 -> "F7")
* Translate hex values of 8-bit bytes into their decimal
equivalents.
> (For example, 16 -> 22)
* Translate decimal values into their string literal representation
> (For example, 22 -> "22")
We are using an older version of LabView (v4), but it should be able
to do the logging we need to do.
We are amazed at how hard this is to do in LabView, given how much
easier it is in C-family languages. We really hope there is some
knowledge out there. If you need more info, please see below. Thank
you in advance!
-> Here is the long description of the problem:
The literal string representation of the hex value of the first byte
represents the first two numeric characters of the display. So, for
example, if we get a hex value of 52 for the first byte, this means
that the measuring instrument is displaying 5.2 on its display. Yes,
this is its scheme (and it's a Varian instrument!)
The remaining precision in the measurement is sent in the second byte.
The literal string representation of the decimal value of this second
byte contains the digits for the remaining precision. So, for
example, a second byte with a hex value of 16 means that the digits
for the remaining precision in the measurement are "22".
The exponent is sent in the third byte. The translation (via two's
complement translation) to a signed integer from the hex value of this
third byte forms the value of the exponent. So, for example, F7 means
that the exponent is -9.
To sum up, if the hex values for a three-byte set (8-bit bytes) were
these:
52 16 F7
then the display of the measuring instrument will read '5.222 E-9'.
It is the literal representation of this value that we would like to
log to the file (disk file). In other words, we'd like a log file
with lines in it that contained the reading in final form: "5.222 E-9,
4.995 E-9, 4.994 E-9", and so on.
Here is a related
<a href="http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&[EMAIL
PROTECTED]&rnum=2&prev=/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=labview+%2522.vi%2522+ascii+decimal">newsgroup
posting</a>.
We can handle the last byte by a simple, short lookup table. But we
need to know how handle the first two bytes.
Sincerely,
- Chris Balz.
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