Error in Reading from spreadsheet tool

Hi all,
In my application I am using a Read from spreadsheet function to display the contents of a txt file saved in my computer continuously every 3 mins. This txt file gets updated once approximately every 3 minutes. Now the problem which I am facing is, If the txt files is getting updated at the exact time when the vi is trying to open the txt file it gives an error saying, "file already open!! Continue or Stop" If I press Continue it misses the values from the file. Is there any alternative to avoid this happening. It happens only once or twice in an hour. But still this error becomes fatal as there is a data loss.
Can anyone please help find a way to avoid this error.
Regards,
Nitz

Hi Nitzz,
If you are accessing the same file frequently in two different places then access it using the low level file IO functions.
Open the file reference at start and keep that in memry using global variable or functional global then close the same at the end of the application.

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Read from spreadsheet file

Hi! I am a beginner labview user and I have a problem reading data from a
..xls file. I have written in columns the data that i want to present in a
waveform graph through labview. I give the path to the Read From Spreadsheet
File tool and i connect a true constant in the "transpose" terminal. The Run
button shows me no error but all I get in my waveform graph is a x-axis
line. Could someone help me? Thanx

You say that you want to read data from a .xls file. You use Read From Spreadsheet File to get the data into LV.
You have mixed some things. A .xls file is NOT a spreadsheet file. It is a file which could be read by MS Excel and some other tools which have import filters for this file. Read from Spreadsheet File is not such a filter.
A spreadsheet file in the context of LV is a text file where the cells of a row are separeted by a tab and the rows are separated by a end of line.
A save thing is use Active-X automation to communicate with MS Excel. Let it load the file and read out the cells. The are examples in LV help and in the dev zone. You must have installed and licenced MS Ecxel on your target machine. Maybe someone has written such a fil
ter for LV but I don't know it.
The other way will only work if you use US local settings and the data is in one worksheet. Save the file with the extention .txt. So Excel will generate a text file of the correct format. Excel will use the regional settings of your machine. You can read in this file with Read From Spreadsheet File. Unfortunatly this will use fixed settings which are the same as for US regional settings.
Waldemar
Waldemar
Using 7.1.1, 8.5.1, 8.6.1, 2009 on XP and RT
Don't forget to give Kudos to good answers and/or questions

Read from spreadsheet: a way to automatically continue if the file is missing? (Rather than having to push "continue")

Hi,
I'm using the "read from spreadsheet file.vi" to read in data from a file that may or may not be present. The data isn't required - it's optional data; nice to have but not everybody will use it.
Of course, if the file isn't present, I get an "Error 7 occurred at Open File+.vipen File", and I have the choice of pushing either the "Continue" or "Stop" button. What I'm wondering is: is there a way to just have LabVIEW automatically continue if the file is missing? Perhaps it could alert the user to the missing file, but continue anyway? Normally I'd handle this by wiring the Error output of the function to an error indicator. But the "read from spreadsheet file.vi" function doesn't appear to have an error output.
I think my description of my question is sufficient, but I'm attaching a snippet of my LabVIEW code that shows the read from spreadsheet file function in question, and the error I get when the file is missing.
Thanks,
dan
Solved!
Go to Solution.
Attachments:
labview-read-sprdsht-error.png ‏27 KB

Dan_the_Clam wrote:
Why oh why do people hate them so much! I'm a friend of local variables!
1. They use more memory
2. They require something on the front panel (even if hidden). So that is yet another copy of your data
3. They break data flow
4. RACE CONDITIONS!!!
Dan_the_Clam wrote:
my code evolves and tends to sprawl a bit.
That tells me you do not have a good architecture to begin with. It also tells me you need to modularize your code more and use subVIs.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
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Is there a file size limit when using Read From Spreadsheet File?

I'm trying to read in a large file, about 52mb, 525600 lines with 27 fileds in each line using "Read From SpreadsheetFile.vi". I then search the 2D array for -999, which represents bad/no data in that field and total the number of fields with -999 in it. This all works on 3 months worth of data. The program is giving me an out of memory error and stopping in the case where the read takes place on the large one year file. So my question is does the Read from Spreadsheet file have size limitations? Is there a better way to do this? Thanks in advance for the help.
ssmith
Solved!
Go to Solution.

Camerond--
Thanks for the help. I recreated the VI you posted and unfortunately it doesnt work. It looks like the index array vi is only looking at the zero index and not the other 26 fields in each row. This would probably require a FOR LOOP to go through each field index. This is what I have and it works on a smaller version of the file. For some reason LV is using up bucket loads of memory to run this smaller file and crashes running the 60MB file. I've attached one of my vi's to solve this problem and the smaller data set. You'll see in the beginning that I trim some columns and rows to leave just the data I want to scan. Thanks again for the help.
I just tried send 3 months worth of one minute data and it failed. So here is a really small version, 20 minutes worth of data. Does anyone see anything that would cause memory usage issues here?
ssmith
Attachments:
Find-999NoLoops.vi ‏17 KB
TEST2MET.txt ‏3 KB

Lightroom encountered and error when reading from it preview cache and needs to quit

A power outage caused my Lightroom 5.2 to shut down without closing. When I powered back up and opened lightroom it gives me an error "Lightroom encountered and error when reading from it preview cache and needs to quit" and then it says it will try to fix it the next time it opens. I have opened it 20 times and it is not fixing it. I removed the program completely and upgraded to 5.5 AND it is still giving me the same error. Is my catalog corrupt or something? I had it set to automatically load the most currently used catalog, so it is not allowing me to open or start a new catalog either. HELP!!!

Search the forum, this has been answered many times.

I'm unable to open up Lightroom 5, I get this message in a pop up box: "Lightroom encountered an error when reading from it's preview cache and needs to quit" Underneath that is "Lightroom will attempt to fix this problem the next time when it launches."

I'm unable to open up Lightroom 5, I get this message in a pop up box: "Lightroom encountered an error when reading from it's preview cache and needs to quit" Underneath that is "Lightroom will attempt to fix this problem the next time when it launches." It hasn't, what should I do? Thanks Shawn (Irish Se7en) .

Can you try to rename (not delete!) the folder named "YOUR_CATALOG_NAME Previews.lrdata" and restart Lightroom?

"Lightroom encountered and error when reading from its preview cache and needs to quit"

I keep receiving this error every time I open LR, "Lightroom encountered and error when reading from its preview cache and needs to quit" and the app won't open. It said LR would try and fix this error next time I opened it but the error remains. I tried uninstalled and installing the app and the error remains.
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Talked to Adobe support this morning, this is their response in case anyone else is looking for help. I'm running a Windows 7 box, LR 5.6.
Gokul: Click on start and type %appdata%, then open roaming folder.
Edward: ok
Gokul: Open Adobe folder.
Gokul: Open Lightroom folder.
Gokul: Open Lightroom folder> Preferences.
Edward: ok
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Edward: it shows me a welcome screen and is asking me to select my country
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Edward: my original catalog?
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Edward: testing integrity of catalog
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Gokul: Please check if you can re-launch it again.
Edward: yes, it worked!
Gokul: Excellent!
Gokul: Since your preferences were corrupted you were facing issue so we renamed the preferences file to reset it.
Edward: aha....ok
All of my import/export presets were intact along with develop user presets. I'm happy as a clam for my $10/month!

LR encountered an error when reading from its preview cache and needs to quit.

I have the 30 day trial version of Lightroom. I was able to use it for one week, but the past 1.5-2 weeks, it has been locked up and giving this error message. How do I resolve the problem? And how do I reset the 30 day free trial? I would like to have time using the product, before deciding on the annual contract.
"LR encountered an error when reading from its preview cache and needs to quit. Lightroom will attempt to fix this problem the next time it launches."
Thank you.

Delete the preview cache from the Lightroom folder in your Pictures folder if you used the default placement. It has the extension .lrdata.
You cannot reset the trial period.

I keep receiving this error every time I open LR, "Lightroom encountered and error when reading from its preview cache and needs to quit" and the app won't open. It said LR would try and fix this error next time I opened it but the error remains. I tried

I keep receiving this error every time I open LR, "Lightroom encountered and error when reading from its preview cache and needs to quit" and the app won't open. It said LR would try and fix this error next time I opened it but the error remains. I tried uninstalled and installing the app and the error remains. I have windows 8. Can anyone please help???

Use Windows Explorer to open the folder containing your catalog. The normal location is Pictures\Lightroom. Locate a folder with the extension .lrdata and delete that folder. Then you should be able to start Lightroom again, and Lightroom will begin building and new previews folder. Do not delete anything else.

It says Lightroom encountered an error when reading from a previous cache and needs to quit. Light room will attempt to to fix the problem the next time it launches.

how do i fix this. It says Lightroom encountered an error when reading from a previous cache and needs to quit. Light room will attempt to to fix the problem the next time it launches.

Have a look at this thread.
Lightroom encountered an error when reading from its preview cache and needs to quit. Lightroom will attempt to fix this problem the next time it launches"."

Error Launching LR 5: "Lightroom encountered an error when reading from its preview cache and..."

Error Launching LR 5: "Lightroom encountered an error when reading from its preview cache and needs to quit. Lightroom will attempt to fix this problem the next time it launches."
I've tried renaming my catalog.lrcat file. I've copied over my most recent backup of the catalog.lrcat and that didn't work either.

On Mac:
PS - to open the previews "folder" (a "package" is just a "special" folder) on Mac, ctrl-click and choose "Show package contents.." - same way you open any other special folder, like .app or .lrplugin..
Rob

Upgraded to 5.4 when opening lightroom get a message "encountered an error when reading from its preview cache and need to quite" tried this several time but get the same eror message

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Delete the preview cache using your operating system. It is a folder whose name ends with Previews.LRDATA. Do not delete the Lightroom catalog, which ends with .LRCAT

When my lightroom opens up I keep getting an error message that states, "Lightroom encountered an error whne reading from its preview cache and needs to quit" I have relaunched it a number of times and keep getting the same message.

when my lightroom opens up I keep getting an error message that states, "Lightroom encountered an error whne reading from its preview cache and needs to quit" I have relaunched it a number of times and keep getting the same message. Any thoughts on how to fix this?

You need to delete your preview cache and have Lightroom rebuild it. Cache location can be found here.
https://helpx.adobe.com/lightroom/kb/preference-file-locations-lightroom-41.html
Why And How To Clear Your Lightroom Cache - Lightroom Fanatic

Lightroom 5 is not opening it gives me an error message there is an error when reading from its preview cache and needs to quite

lightroom 5 is not opening it gives me an error message there is an error when reading from its preview cache and needs to quite
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Check this thread. Your Previews Cache files are corrupted.
Re: preview cache?

Lightroom encountered an error when reading from its preview cache and needs to quit. Says Lightromm will attempt to fix the problem the next time it launches, but on every re-launch I get the same message. Any clue as to how to fix this problem?

I recently updated my HP laptop's OS from WIndows8 to WIndows8.1. When I went attempted to open Lightroom5 I got the following message:
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reset your preferences, Resetting (or 'Trashing') the Lightroom Preferences file - Lightroom Forums

Error in Reading from spreadsheet tool

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