VI Logger to Database?

[Dave K]

I've been asked to evaluate a Logging project and the engineer had specified "VI Logger" as the logging package to use to monitor and store a number of variables associated with furnace operation. A cursory review of the available documentation seems to indicate that VI Logger is incapable of logging to a real database (SQL Server, Oracle).

It seems inconceivable that such would be the case (I consider it a required capability in any logging application)... am I missing something obvious?

[Otis]

VI Logger is an application that is designed to allow people to easily log values to a file. VI Logger is not designed for database functionality.

Once that file is created you can then use whatever protocol your databases use to integrate your file into the database.

[Kennon_Cotton]

Dave,

VI Logger does log to a database, although it is not a generic database like Oracle or Access. VI Logger only stores data to the NI Citadel database. Citadel was originally written for use with our Lookout and LabVIEW DSC products as a high throughput database for logging measurement data. It is still used by those products and VI Logger. While it is a proprietary database (a drawback of the design for measurement data and for speed), there are a few ways to access the data in it:

1. The Historical data graph in VI Logger that allows you to browse through the data you have acquired.

1. New for VI Logger 2.0 is the View in Excel button / popup option that takes the data visible on the VI Logger graph and exports it to Excel.

1. There is a pop up option in the VI Logger tree of tasks and data runs that allows you to export to text files. Easily to delimited data or html, but you also use a custom text format.

1. NI DIAdem can also be used to generate custom reports and analysis from the VI Logger data stored in Citadel, through the View in DIAdem button.

1. If you have LabVIEW installed, VI Logger will install a set of VIs that allow you to read the data stored in the Citadel database and you can then analyze it, etc.

VI Logger is a stand-alone data logger application designed for people who want to do data logging and retrieval without having to write a program. It may not fit your requirements if you have to log to a certain database format or need to share data in a certain way, that isn't already part of VI Logger. This would require using a programming language such as LabVIEW to write a program so you can have the data stored in what ever format you want.

If you've evaluated VI Logger 1.x, you should take a look at the new 2.0 version that released a couple of weeks ago. There will be an evaluation version of it for download very soon.

Kennon Cotton
Group Manager VI Logger R&D
National Instruments

Message Edited by Support on 05-29-2007 03:10 PM

[Dave K]

Thanks for the reply!

Well at this point I think we're going to write the app in VB.Net or possibly Labview, if the 2.0 version of VI Logger provides open database connectivity (In our case that means SQL Server or Oracle for low bandwidth and OSI PI for high bandwidth) let me know because I liked the simplicity of the product.

Thanks again.

[Kennon_Cotton]

Dave,

VI Logger 2.0 does not add support for logging to other databases. We'll keep that feedback in mind for future versons. I'm glad you otherwise liked the product.

I'm of coursed biased, but I'd recommend using LabVIEW for writing your data logging application. You can read/write to your database through ActiveX or DLL calls, or if it is an ADO database you should consider the Database Connectivity Toolkit. The toolkit wraps the ActiveX calls into easier-to-use, higher level functions.

Good luck with your application,

Kennon

[JohnV]

When using the data logging - to Excel function.  How do I control how much data is written to the excel file?

It does not seem to corrrelate with the N samples and Sample rate parameters set in the channel set-up.  What am I missing?

Also, is there a way to scale the x-axis of the window to just show # of samples or to put it into a Strip-Chart type mode?

-John

[brahe]

The number of scans written to Excel corresponds to the number of scans you view in the Historical Data viewer.  If you want to export all the data to Excel, zoom out so that you have all the data in the graph.  Or, you can right-click on the trace and export the data to a text file instead.

You can only choose between absolute time or relative time for the x-axis.

Hope this helps.

[JohnV]

I get 100 scans in Excell regardless of the size of the Real Time Data Window. 

Could you expeimenent and tell me exatclt how you're getting more.

I have N = 1000 scans at 1000 Hz sample rate.  Continuous mode.

Sincerely,

-John

[JohnV]

Ok,

Figured it out.  There is a bug that unless you check "View in Excel when Task Stops" it will always write 100 samples.

My next dumb question:  when you set the sample rate (Hz) is that per channel?

-John