Integration using the Time Domain Math Express VI

[MechanicallyInclined24]

Hello, I am new to LabVIEW so please pardon this possibly simple question.

I have searched around and I can't figure out the timebase (dt) for the Time Domain Math Express VI integration function.

I am trying to use it to integrate an acceleration waveform, and I need to understand what the timebase is so I can calculate the units of the output value.

Thanks in advance!

[altenbach]

A waveform datatype already contains timing information.

[MechanicallyInclined24]

So how do I determine the units of the output if I was integrating for example, instantaneous power to get power used over time?

[RavensFan]

The units will be the units of Power times the units for time.

So if your power is Watts, and the dT is seconds.  The it will be Watt-seconds.

If the power is kW and the dT is based on  hours, then it will be kW-hrs.

[MechanicallyInclined24]

Thank you for the reply. I understand that, and I guess I should have been more clear about what I was asking. What I don't understand is how to determine what dt is. Is it seconds, miliseconds, microseconds? How is it determined? Is it based on the time it takes to execute a loop?

[RavensFan]

dT is technically just a number as far a LabVIEW is concerned.  If it is 1, then it is 1 unit of time interval.  If it is .001 then it is a thousandth of a unit.  What the size of the unit is depends on where the data is coming from.  Typically if you are dealing with Waveform datatypes, and you are getting data from a DAQ device, the unit is practically seconds.  So a dT of 1 on a DAQ card would be 1 second.  A dT of .001 would be 1 millisecond.

[MechanicallyInclined24]

So if I am using the DAQ Assistant to collect waveform data, will the dt be 1/ the sampling frequency? Does it depend on n (the number of samples per cycle in the DAQ Assistant)?

[altenbach]

I would think it dt always in units of seconds.

[BillMe]

dt has nothing to do with the # of samples, it's the rate at which the data is sampled, dt = 1 / Fs.