Periodic logging cannot be implemented in a task, you need to implement this adding a LabVIEW VI to your DAQExpress project and call the task from the LabVIEW VI
as explained in Programming Using DAQExpress
Once you have your task being called from a LabVIEW VI, there are two ways to implement periodic logging in DAQExpress, using the DAQmx Task Properties or the Storage palette functions.Configure Logging Using the DAQmx Task Properties
- Add a DAQmx Task Properties node to the task in the LabVIEW VI.
- Add the Read >> Logging properties shown in the screenshot to the task and configure as required.
You can define the time of each log file based on the acquisition rate and the number of samples per file. This is the simplest method, requiring minimal programming, but also offering minimal flexibility and control of the TDMS file. For more control and flexibility, refer to the next method.Configure Logging Manually Using the Storage Palette
palette provides you with the VIs you will need to manually open/create, close, and write to a TDMS file.
Refer to the Periodic Logging
shipping example in DAQExpress by going to Learning
>> Built Applications
from the welcome screen to learn how to implement periodic logging with the VIs in the Storage
There are two GVIs in the example:
- Continuous Logging.gvi shows you how to log continuously saving the data in multiple files, creating a new file when the time specified in the New File Interval in Minutes control is reached.
- Periodic Logging.gvi is useful if you don’t to save all the data, because it allows to save a new file every time the Logging Interval in Minutes is reached, saving only the amount of data specified in Logging Duration in Seconds.