Hello, I am working on a data logger for an older MTS load frame system at a university doing a long cyclical (~0.1-1 Hz) test that may go millions of cycles. The logger is recording displacement, load, elapsed time and cycle counts as received from a pulsed value from the hardware controller. The amount of data is currently too much even though we are recording every Nth cycle (10, 50, or 100) with the current program listed as DataflowLoop.vi. I am trying to limit this recording to only the max/min values of a cycle but need to pull from a full sampled wave to avoid aliasing as the peaks are important for verification. The current program does occasionally miss counts already, about 100-200 out of 300,000, but will likely run into more issues if we go to calculate max/min. I decided to try to recreate the code in a producer/consumer loop in order to continuously look for the counter and receive data and perform the calculations in parallel. Additionally, I would like the system to trigger a higher recording, maybe the full sampled waveform and not max/min when the specimen goes past a displacement limit suggesting that a rapid failure is starting in an effort not to miss this data. I am getting data and triggers, but I think I am not clear on what the best practice would be here on the DAQmx tasks start/stop/clear in the producer loop. Is it better to do continuous samples and start once like it is now or should I use finite samples and start/stop inside the producer loop like the dataflowloop test? I did get some -200088 errors on that. This is my first foray into queues, and I am wondering if my current setup is at risk of buffer overrun over such a long test as well. I have not put in the max/min feature yet, but I plan to index the array to pull out the load and displacement arrays ->array to max/min then bundle back with the cycle count to record. Any thoughts or help would be appreciated. This is LabVIEW 2020, but I am writing it for a DAQ system running LabVIEW 2016 on I believe a pci mio 16xe 10. Thank you, Chris

LabVIEW

High Cyclic Fatigue DAQ with Failure Triggering Increased Rate / Shutoff - Producer/Consumer Pattern

Author

I have been working on the implementation of the suggested changes and getting a further understanding of tdms. I think I may have gone down a rabbit hole though in the use of variants within the queue and I am not sure why I cannot unbundle these the way I bundled them. The clusters passed to the queue consist of an enum, variant, and string. I used variants to pass multiple data types to the queue, but I think it may be simpler done with converting the inputs to double instead. Another thought is multiple queues though I thought that might get into some messier issues.

Am I going down the right road here? Thanks for the help.