You can integrate both your NI 9237 and your NI 9215 in one FPGA VI. Once you add both of your modules and FPGA I/O to your project, they should both appear when editing an FPGA I/O node on your FPGA VI.
The best way to store your data to a text file with timestamps would be to write your data to a shared variable in a high-priority acquistion task, and then read your data from the shared variable and write it to a text file in a low-priority acquisition task (See Figure 12 of the first article linked below).
I would also recommend that you use a DMA FIFO to transfer your data efficiently. Please read the Developer Zone article below for more detailed information on using DMA FIFOs, in addition to LabVIEW Help. Thanks!
Hi Megan, Thanks for the info. The FPGA module data has to be plotted with respect to timestamp.
when i plot the data with timestamp as x-axis, that is , i have a while loop in the host VI which runs on the RT. i have not specified any time delay in host. The timestamp on the chart does not come correct. My FPGA loop rate is set in micro secs.
The timestamp has to be the RT controller timestamp. how do i set the time correctly.
Does plotting put overhead on the execution time.Thanks.
I have used the code generated by the FPGA Wizard for the 9205/9263 and then copied blocks from the 9237 Getting Started example into a similar structure, so I've got something working even if it's not the "best". I'll ask my local NI engineer about DMA when he next visits.
And hey, speed is relative!
Did you have to use any sort of filtering for the signals read from the FPGA. I am reading LVDT outpu volts thru NI 9215 and CRIO module.
When the LVDT is at a fixed position, i want the voltage read in my VI as constant to six decimal places. But that is not happening. I have the data rate of 9237 set as 50Khz and integrated both modules. (using NI example 19237 module). My voltage value at a fixed position flickers that is if voltage is 2.00 v,
my readings is not constant after 3decimal places. Checked for the connections and that looks OK.