Maximum length of a text channel

[mrme]

Hi,

I am unable to have a text channel length greater than 3000000.  The documentation talks about a max length of 2^32 which is much greater.  Is it different for text channels? or does it depend on the length of the text strings stored?

I have Diadem 2012.

Thanks!.

[brandonj]

DIAdem can load 2^32 values per channel. I was able to load a file with length more than 3,000,000 (about 20 characters per value). I am using DIAdem 2015 SP2. A large file can take a long time to load, especially if it is on the same order of magnitude as RAM. Can you describe the symptoms you are seeing? Does DIAdem throw an error or does it appear unresponsive?

[mrme]

Hi Brandonj,

I have a script which concatenates channels from many individual TDM files.  Usually Diadem throws an error -'Target channel (channel/max.length/required: is too short')before all the concatenation is complete.  Sometimes the concatenation completes, but then it is impossible to save the file (another error message - 'Cannot store complete internal data in the file') .  At first I thought I had met some limit on channel length, but this does not seem to be the case.  Diadem appears to moan about a long text channel populated by strings of about 20 characters length.  But the channel length is far below 2^32.  Also, I appear to have sufficient memory for the task.

I see some other posts (mainly older ones) from people with a similar issue.  I will have to look deeper.....

Thank you for your help!

Thomas

[AndreasK]

Theoretically text channels can have this length,

BUT
text channels eat lot of memory. Thats where they differe from numeric channels.

Numeric channels can be hold in file components, text channels are stored in

the TDM XML file itself. Because the XML tree eats up lot of memory it fails. 😞

TDMS might help because it needs less memory during save/open but potentially text channels have memory issues.

64 bit DIAdem version might help because it offers more memory.

Maybe you can try to switch to a kind of enumeration channel. I assume not all values are different.

Sorry. There is no easy solution.

Andreas

[Brad_Turpin]

Hey Thomas,

Just to be clear, the channel value limit in DIAdem 2017 and prior versions is 2^31 values, not 2^32.  In case you were anywhere close to the 2^32 metric, you might have actually already been beyond the actual limit of 2^31.

Brad Turpin

DIAdem Product Support Engineer

National Instruments

[mrme]

Hi Andreas,

My text channels contain date and time info.  I have decided to change to date channels (hence my other post).  Hopefully, it will work better.

Thanks!

Thomas

[mrme]

Hi Brad,

My text channels have a length of about 6 000 000. They contain date and time data.   Usually, the problem manifests itself when the channels have grown to 3 000 000 during concatenation. 

I am modifying the script to place the data in date channels.  Hopefully, this will work better.

Thanks for the support.

Thomas

[mrme]

I have modified the script to store the time/date data in 'Time' channels as opposed to 'Text' channels.  In my tests so far, the problems have not reappeared. 

Thanks to Andreas, Brad and Brandonj for your help!

Regards,

Thomas