Cast string to single precision

Hi,
I try to write a communication between a PC and a DSP which is
programmed to
understand some kind of ModBus. I tried to use MBmaster.vi, a freeware
of AIRtech in the netherlands.
I was successfull to 90% after a very short time - I get back a string
from the DSP which makes sense.
The only problem is to *convert* the 4Byte=8Hex=32Bits(=IEEE754 single
precision format) into the LabView single precision number it does
represent .
In other programming languages like C I think I could do this easily
on a very low level procedure or with one of these dangerous casts.
As a newbie to LabView I could not found neither one VI to do this or
find out which simple combination of VIs could solve the problems.
Are there any cracks
here who know *the* easy solution??
Thanx & Regards
Urs Bögli

"Doug (CapeFl)" wrote in message news:<[email protected]>...
> Did you check the VI functions under Functions>String>Additional
> String to Number Functions?
> There are quite a few for converting to/from Hex, etc. I've used them
> for concatenating 4-bit strings into an 8-bit string (to get an 8-bit
> byte/word), also converting to/from Hex using some of the VIs I
> mentioned.
> Good Luck, Doug
Dough,
as a programmer for twenty years I have some problems to understand the way
labview does work with types and casts - other languages are much clearer about it
- or have I not found the ultimative help area yet ???
May I ask you to send me the VI off list?
thanks
Urs

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Perhaps what you are doing is an exercise in the programming of the math conversion of the bytes.
But if you are just interested in getting the conversion done, why not use the typecast function?
If the bytes happen to be in the wrong order for wherever you need to send the string, then you can use string functions to rearrange them.
Message Edited by Ravens Fan on 10-02-2007 08:50 PM
Attachments:
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Copying a table with the right-click menu in schema browser fails to copy comments when string has single quote(s) (ascii chr(39))

Hi,
I'm running 32-bit version of SQL Developer v. 3.2.20.09 build 09.87, and I used the built in context menu (right-clicking from the schema browser) today to copy a table. However, none of the comments copied. When I dug into the PL/SQL that the menu-item is using, I realized that it fails because it doesn't handle single quotes within the comment string.
For example, I have a table named WE_ENROLL_SNAPSHOT that I wanted to copy as WE_ENROLL_SNAPSHOT_V1 (within same schema name)
1. I right-clicked on the object in the schema browser and selected Table > Copy...
2. In the pop-up Copy window, I entered the new table name "WE_ENROLL_SNAPSHOT_V1" and ticked the box for "Include Data" option. -- The PL/SQL that the menu-command is using is in the "SQL" tab of this window. This is what I extracted later for testing the issue after the comments did not copy.
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declare
l_sql varchar2(32767);
c_tab_comment varchar2(32767);
procedure run(p_sql varchar2) as
begin
     execute immediate p_sql;
end;
begin
run('create table "BI_ETL".WE_ENROLL_SNAPSHOT_V1 as select * from "BI_ETL"."WE_ENROLL_SNAPSHOT" where '||11||' = 11');
select comments into c_tab_comment from sys.all_TAB_comments where owner = 'BI_ETL' and table_name = 'WE_ENROLL_SNAPSHOT' and comments is not null;
run('comment on table BI_ETL.WE_ENROLL_SNAPSHOT_V1 is '||''''||c_tab_comment||'''');
for tc in (select column_name from sys.all_tab_cols where owner = 'BI_ETL' and table_name = 'WE_ENROLL_SNAPSHOT')
    loop
   for c in (select comments from sys.all_col_comments where owner = 'BI_ETL' and table_name = 'WE_ENROLL_SNAPSHOT' and column_name=tc.column_name)
   loop
   run ('comment on column BI_ETL.WE_ENROLL_SNAPSHOT_V1.'||tc.column_name||' is '||''''||c.comments||'''');
end loop;
end loop;
EXCEPTION
WHEN OTHERS THEN NULL;
end;
The string of the table comment on WE_ENROLL_SNAPSHOT is this:
WBIG table of frozen, point-in-time snapshots of Enrolled Students by Category/term/pidm. "Category" is historically, and commonly, our CENSUS snapshot; but, can also describe other frequencies, or categorizations, such as: End-of-Term (EOT), etc. Note: Prior to this table existing, Census-snapshots were stored in SATURN.SNAPREG_ALL. All FALL and SPRING term records prior-to-and-including Spring 2013 ('201230') have been migrated into this table -- EXCEPT a few select prior to Fall 2004 (200410) records where there are duplicates on term/pidm. NO Summer snapshots existed in SNAPREG_ALL, but were queried and stored retroactively (including terms prior to Spring 2013) for the purpose of future on-going year-over-year analysis and comparison.
Note the single quotes in the comment: ... ('201230')
So, in the above PL/SQL line 11 grabs this string into "c_tab_comment", but then line 12 fails because of the single quotes. It doesn't know how to end the string because the single quotes in the string are not "escaped", and this messes up the concatenation on line 12. (So, then no other column comments are created either because the block throws an error, and goes to line 22 for the exception and exits.)
When I modify the above PL/SQL as my own anonymous block like this, it is successful:
declare
c_tab_comment VARCHAR2(32767);
begin
SELECT REPLACE(comments,chr(39),chr(39)||chr(39)) INTO c_tab_comment FROM sys.all_TAB_comments WHERE owner = 'BI_ETL'   AND table_name = 'WE_ENROLL_SNAPSHOT' AND comments IS NOT NULL;
EXECUTE IMMEDIATE 'comment on table BI_ETL.WE_ENROLL_SNAPSHOT_V1 is '''||c_tab_comment||'''';
for tc in (select column_name from sys.all_tab_cols where owner = 'BI_ETL' and table_name = 'WE_ENROLL_SNAPSHOT')
    loop
   for c in (select REPLACE(comments,chr(39),chr(39)||chr(39)) comments from sys.all_col_comments where owner = 'BI_ETL' and table_name = 'WE_ENROLL_SNAPSHOT' and column_name=tc.column_name)
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end loop;
end loop;
EXCEPTION
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On lines 4 and 8 I wrapped the "comments" from sys.all_tab_comments and sys.all_col_comments with a replace command finding every chr(39) and replacing with chr(39)||chr(39). (On line 8 I also had to alias the wrapped column as "comments" so line 10 would succeed.)
Is this an issue with SQL Developer? Is there any chance that the menu-items can handle single quotes in comment strings? ... And, of course this makes me wonder which other context menu commands in the tool might have a similar issue.
Thoughts?
thanks//jacob

PaigeT wrote:
I know about quick drop, but it isn't helpful here. I want to be able to right click on a string or array wire, navigate to the string or array palette, and select the corresponding "Empty?" comparator. In this case, since I do actually know where those functions live, and I'm already using my mouse to right click on the wire, typing ctrl-space to open quick drop and then typing in the function name is actually more work than navigating to it in the palette. It would just be nice to have it on hand in the location I naturally go to look for it the first time.
I don't agree with this work flow. Right hand on mouse, left hand on home keys. Pressing CTRL + Space is done with the left hands, and then you could assign "ea" to "Empty Array" both of which is accessible with the left hand. Darren posted a bunch of great shortcuts for the right handed developer.
https://decibel.ni.com/content/docs/DOC-20453
This is much faster than waiting for any right click menu navigation, even if it is found in the suggested subpalette.
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Cast string to single precision

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