no time recorded using DAQ assistant

[errcricket]

greetings.

i am using a NI USB-6210 and i have a very simple vi that records the voltage and puts it into a text file (spreadsheet). when i look at the text file, i can only see the voltage, not the time. i know the sampling rate, but i would like to have it placed automatically in the text file as well. should i add a timer or have i connected something incorrectly (i have attached VI)? also, i am verifying the output with a multimeter and a resistor box so i know the values are correct. however, when i change the resistance - say 5 times, my output shows only the last voltage. Suggestions?

thanks in advance.

[errcricket]

here is an image of the block diagram.

[Dennis_Knutson]

You are removing the timestamp data when you convert the dynamic data to a 2D dbl array. Why are you using both a Write to Measurement file and a Write to Spreadsheet File? The lvm file has the t0 and relative time information in it. Do you not like the format? If you want to do something different, then try converting the dynamic data to a waveform data type. You can then use the Get Waveform Time Array, convert that and the Y data to strings and use the string type of the Write to Spreadsheet.

[errcricket]

why was i using both...chalk it up to inexperience.

so i removed the spreadsheet and am using only the write to measure file. it is working properly. my initial error with this was not properly configuring my save actions or something like that. when i changed the actions, i got more than a blank file.

even though i will use the measurement file, it is good to know about the removal of the data timestamp with 2D dle array. thank you.

my next question is that regardless of my recording time, i am only getting 1 second and the final voltage. i am probably only getting the final voltage because i cannot change the resistance fast enough to capture it. suggestions.

[Dennis_Knutson]

That's something I didn't pay any attention to with the first question. When you pass data out of a while loop, you only pass out the very last iteration. You can right click on the exit tunnel and select 'enable indexing'. This will create an array that you would have to index to individual elements with your write function inside a while loop. Indexing and unindexing dynamic data is a pain and something I would not do. The easiest thing to try is to put the file write inside the loop. You might also try the Append signal function and a shift register. That way, you can place the file write outside the loop.

[errcricket]

thank you DK.

i discovered that it was an issue of sampling rate vs. the number of samples...100/100 = 1s. who knew. i don't think it is an issue of placing it inside or outside of the loop - but as you are knighted, i am certain you have a better understanding. so i will rephrase - it made no difference to my data where the placement of the write to measurement file icon was. i did change the number of samples and was able to get up to 10 seconds of data. my new issue is error-200284. there are several threads out there, i just have not read them all  - but in summary...
it is nice to check out this vi and see that it is measuring the voltage properly, but 10 seconds is a smattering of the time i need. the experiment i will be running lasts for ~70 minutes. when i put in this information into the DAQ assistant and start to run the VI, that is when i get the error.

and do you have any suggestions as the the error? and as an aside, do you still think the WTM file is still the way to go?

thank you for your time and help.

 - e