Express VI's vs other VI's

[dheeraj2102]

I am trying to improve the speed and efficiency of my programs in LabVIEW for Data Acquisition. 

Which Vi's are better? Express VI's or other VI's? 

1. Write to Measurement File or Write to Spreadsheet File? The former involves the conversion of 2D DBL data to dynamic data whereas the latter involves number to fractional string converter. Which is more efficient/faster?

2. Time Delay or Wait for next ms multiple ?

3. Formula calculator or Polynomial Evaluation VI ??

Please tell me which of these are the best to be used in data acquisition prpgrams! Thanks 🙂

[RavensFan]

Express VI's are good for getting something started working quickly, particularly for new users.  Some of the more detailed stuff is preprogrammed for you by what you fill into the Express dialog box, and the implementation details are hidden in the background.  But as soon as you need to do something that stretches the boundaries of an Express VI, you are better learning some real LabVIEW programming so you can customize your code to better suit your situation.

The Express VI's also use the blue dynamic datatype wire.  You might as well call it an Express wire.  It can represent many different types of data, and exactly what it is doing is pretty much hidden from the programmer.  But because it hides these details, you never really know what kind of data it is carrying.

1.  I would tend to use the Write to Spreadsheet File File so I can avoid the dynamic datatype and directly control how the data is being written to the file.

2.  I rarely use Wait for next msec multiple.  The Wait (msec) is the more commonly used function.  The Time Delay Express VI is more like the Wait, and not like the Wait next msec multiple.  One advantage to the Express VI is it has error wires built in so you can directly control the time of execution of different functions and subVI's without needing to use flat sequence structures to control the order of execution.

3.  I would the basic LabVIEW functions directly and not use the Formula calculator.  The Polynomial Evaluation would be useful, but only in those specific instances where the equation you want to calculate is a polynomial expression.