Logging voltage and current over long time intervals

[Triumph5ta]

Please excuse the lack of scientific knowledge. I am "the IT guy" trying to help someone out now that we have lost our in-house scientist with programming knowledge. He would probably have nailed this in five minutes...

Scenario:

A Potentiostat is being used to run an Electrolytic Reduction process.

The Potentiostat displays its output as "E mV" and as "I mA"

It also has two BNC outlets "I Out" and "E Out"

I will connect I OUT and E OUT to a USB-6002 DAQ and use Signal Express 2015 to log mV and mA over time.

The process can take up to 7 days and the values change slowly therefore we only want to log the values once every 30 minutes. Or even once an hour.

Problem

As present I can set up a Project in SignalExpress OK but I simply cannot work out how to tell it to go to the DAQ every 30 minutes. It wants to log many times a minute. If I do that over a week I will end up with huge bloated log file.

I think this is where I need to specify my logging interval:

I need to use "Continuous Samples" so the data can be easily exported to Excel.

any suggestions gratefully received. I expect this to be incredibly obvious to you but as I said at the beginning I am not a scientist 

[OKors]

if you want one sample every 30 minutes try entering a Rate(Hz) of 0.000555556 and Samples to read as 1.

For 60 minutes your Rate would be 0.000277778

Keep your acquisition mode "continuous".

If you can afford the extra 60 minute gut-check; I would try the rate I just gave you, hit record, make sure you dont get any errors. If you do come back and post them. Also, some hardware has a minimum sample rate regardless of how low you set it. If this is the case w/ any of your hardware you'll know in short order.

If no errors, walk away for 30 or 60 mins and come back and check your data file to make sure you have two sample points in there.

Start with that.
Post back if you hit a wall.


PS, I made a Sample Rate Calculator in Excel years ago for this very purpose.

[OKors]

I need to use "Continuous Samples" so the data can be easily exported to Excel.

any suggestions gratefully received. I expect this to be incredibly obvious to you but as I said at the beginning I am not a scientist 

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Continuous only has to do with how Sig Ex handles the chunks of data coming down the pipe not whether it can be exported to excel necessarily.

In your case the easiest thing to do is add a Save to ASCII step and select .txt file. Go through the options and select what to do if the filename already exists. FWIW, I always select Next file name per run.

If you already had the save part covered, my apologies. From your comment about Continuous samples it sounded as though you may not have.

Also, when using the Save to ascii step, unless you have a need for the additional files/folders and baked-in header information you can avoid using the Record feature;  just use the RUN button (Run Continuously).