Graph Trace Disk Space


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Depends on how often you are taking data.  Data at 1 second uses 60 times as much disk space as data at one minute.  But in general, the persist file is 16 bytes per data point.  That's 8 for the time stamp, and 8 for the value.  Assuming 1 minute data, 13 months = about 560,000 data points * 20 traces = about 11 million * 16 = about 176 meg.  This won't bog down DAQFactory on a modern machine, but you should try and avoid bringing in all 176 meg worth of data at once.    


For performance reasons, I often will create a second channel for each channel that has a slower data rate, say 1 hour, that I use for generating long term trends, but that might be overkill in your case.  Of course if you have 1 second data instead of 1 minute, then we are talking 10.5 gig, which is more memory than a 32 bit app like DAQFactory can handle at once (it is limited to 4 gig like all 32 bit apps).  Then you really will need to have a duplicate slower data set if you want the ability to zoom out and see the entire time span.  

Remember though, that it only matters what data you bring into DAQFactory.  So you can create 1 second data for 13 months on 20 traces as long as you only view, say, at most one week at a time, and scroll it.  It is when you zoom out to 6 months or the full 13 months that you run into problems.

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