Update Pulse Generation

[John_P1]

Hi Emily,

Thanks for the extra info--the E Series DAQ Cards (like your 6025E) do not have Clocked Digital Lines (like M or X Series) nor do they have Buffered Counter Outputs (like X Series).  So, the only option is to re-start the counter tasks in software.  The restarting of the counter tasks is what is taking the extra second and there is not a good workaround without changing your hardware.

I ran the following code to verify what a reasonable re-arm time woud be:

Using the numbers that you provided, I received an execution time of:

5920 ms on E Series Device (PCI 6070E)

5032 ms on X Series Device (PCIe 6353)

The .92 second latency seems comparable to what you are getting--the exact amount of time it takes to re-start the counter is going to be highly system dependant since we are dealing with the latency between your computer and the DAQ device.  The main reason that the X Series gives a better result running the same code is that the PCIe bus has lower latency than the PCI bus.

I have attached the code that I used to obtain the benchmark so you can try it on your own system (saved in LV 8.2).  This is going to be the fastest way to reconfigure your counter if you need an exact number of steps at each frequency.  The alternative is to allow the counter to run continuously with SW-timed updates to the registers which would give a non-exact number of pulses at each frequency but would give 0 delay between configurations (you can change the rate on-the-fly but not the number of samples).

The ideal solution would be to upgrade hardware to a device that supports buffered counter outputs (the most affordable X Series that can do this is the PCIe 6320, but you will need a PCI Express slot to use it).

Best Regards,