Example Code
Products and Environment
This section reflects the products and operating system used to create the example.To download NI software, including the products shown below, visit ni.com/downloads.
- Data Acquisition (DAQ)
Hardware
- LabVIEW
Software
- NI DAQmx
Driver
Code and Documents
Attachment
Overview
This example shows how to shows relative time in waveform chart.
Description
Within the waveform data there exists many different components, one of those components is the time stamp information. The time stamp information can be confusing and may create results that weren't expected. After going through this example you should have a better understanding of the time stamp data.The time stamp data is the number of seconds elaped since 12am, Friday, January 1, 1904, Universal Time. Labview then formats these seconds into the absolute time depending upon your computer's information about time zone and daylight savings.This allows using absolute time with charts very convenient, however it is not so easy to get relative time using waveform data in charts. In order to display the relative time in terms of when the VI was started, that moment at run-time must be known to the program. If the difference is taken between the run-time stamp and the waveform time stamp you will get how many seconds have elapsed since the moment you ran the VI. The image below shows what the chart would show if directly wired with waveform data and the chart that shows the timing axis that starts at zero at run-time.The t0 is time since January 1, 1904 and when viewed as relative time shows up as 900,000+ hours. In order for the time to be zero at run-time, the econds since 1904 at the moment the run button is pressed needs to be subtracted from the t0 of the waveform data.
Requirements
Software
- LabVIEW 2012 or compatible
- NI-DAQmx 9.5.5 or compatible
Hardware
- NI Multifunction DAQ Device
Steps to Implement or Execute Code
- Configure the parameter for the right channel and device
- Connect your hardware appropriately
- Run the VI
Additional Information or References
**This document has been updated to meet the current required format for the NI Code Exchange.**
Example code from the Example Code Exchange in the NI Community is licensed with the MIT license.
Thanks for your kind words, to answer your question, in order to see the absolute time (eg, 10:16AM) of the chart you only need to change the properties of the chart. If you change the properties of the chart that doesn't have the adjusted time, you will get the absolute time. Let me know if you have any other questions.
