Signal peak hold via hardware?

[Gan Uesli Starling]

Needing to capture a peak value. Not willing to rely on sofware timing for fear of missing the actual peak in between LabVIEW read cycles.

 

So...might anyone know of an NI hardware (module or standalone) which can capture peaks on its own, holding that value until the next LabVIEW read query? That is to say, an amplifier with this built-in (possibly as analog) inside the module?

 

Sure, I can build one from scratch, but it seems a feature many others would want. I rather think that NI might have it as an option in one or another module for CompacDAQ, etc. But I fail to locoate it and NI's website is not much help, directing me off in different directions. And yes, I know I asked a similar question one time before, but got only a software answer. I'm specifically interested only in a hardware recommendation. The software iteration loop is intrinsically too slow.

[hooovahh]

Perform a DAQ read using any normal NI hardware, using continuous mode.  Then you can have the hardware read a bunch of values (say 10,000 per second) and once a second read all of them, then perform a Maximum function on it in LabVIEW, then read another 10,000 samples and get the maximum of those 10,000 plus the one from previous.    The cheapest solution I'd recommend (not knowing the full application) is the USB-6008.  Then use any continuous analog input sampling example.

 

The trick here is that it is a software solution, but using hardware timing so you won't miss any values, it's continuously reading, you just have to ask for a chunk of values at a time.

Edited June 24, 2013 by hooovahh

[hooovahh]

I have never used the 6008, and I can't simulate it for some reason (not in the list in MAX) but the spec says supports 10Ks/s sampling rate on a single channel.  I assumed it meant hardware timing, since it would be cruel to say that but require a tight timed loop in Windows.  I just went for the cheapest AI USB DAQ not knowing that NI sold them which don't support hardware timing.  Please correct me if I'm wrong.

[drjdpowell]

Needing to capture a peak value. Not willing to rely on sofware timing for fear of missing the actual peak in between LabVIEW read cycles.

Can you provide a hardware trigger at the high point of your pulse peak?  Then you could trigger the DAQ read at the exact peak.