Dear friends, We are using PCI 6534 to do pattern output, software platforms are C++ and NIDAQmx. The experimetal sequence is following: (1) Output 400,000 samples (32-bit, so all channels are used) upon a trigger (start trigger); Rate: 3MHz; so the total pattern output lasts about 50 ms; Internal on-baord clock; (2) Wait for a few seconds, typically 5s; (3) Output the next 400,000 samples (32-bit) upon a trigger; the sample here is different from that of setp (1); (4) wait for a few seconds and output a new group of 32-bit 400,000 samples. Now I have gone through the step (1), the code used are attached. Do anyone have suggestions how to proceed? Is it possible to load all the three groups of data array to the on-board FIFO, and use start-trigger and stop-trigger to start and stop the generation of three pulse groups? Or is it possible to use the two on-board FIFOs, when the 1st FIFO is output, load data from PCI to the 2nd FIFOand wait, and so on...? Thanks a lot!

Your DAQ process looks good,Keep in mind, the data transfer process for output tasks. The data is created in the application buffer and transferred into the PC buffer then transferred into the onboard memory either by DMA or interrupt. PC buffer to on board memory is pretty consistent and you can reference KnowledgeBase 3F4BMNY7 on appropriate rates. What is difficult to gauge is the transfer time between the application buffer to the pc buffer. Unfortunately, the current method of running this application heavily relies on software operations. These software operations (starting & stopping task) are inherently non-deterministic due to the Windows OS. Your question (1) can be addressed by the above KB but the time that the data is written in the application is not deterministic. Question (2), should be neglible in this application since it’s within the nS range and most of the delay will be found in starting and stopping the task, which could reach mS. There are ways around this, if you have the following hardware.1) An additional device with counters. Upload all samples into the buffer. Import any counter, and use that as the sample clock to trigger the sample sets. Reference the Retriggerable Pulse Train Generation example for your sample clock. 2) X Series Devices support retriggerable DO. Similarly to the above suggestion you can upload all the samples into memory and trigger each sample set. The device uses the DO Sample Clock signal to update the output with the next sample from the buffer. X Series also support retransmit mode, which implies that once all the samples have been sent it restarts. 3) HSDIO devices have scripting ability making this task much simpler. A script is a series of instructions that indicates how waveforms saved in the onboard memory should be sent. The script can specify the order in which the waveforms are generated, the number of times they are generated, and the triggers and markers associated with the generation.

Digital I/O

How to use PCI 6534 to perform pulsed pattern generation

Solved!

Not with the 6534, I recommend HSDIO to utilize scripting to output the waveform of interest.

Regards,
Glenn

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Digital I/O

How to use PCI 6534 to perform pulsed pattern generation

Re: How to use PCI 6534 to perform pulsed pattern generation