Post processing using NI6225

Question

I have 12 NI6225 DAQ Boards (~960 chs).  I want to set up LV8 to read Ch1 on all 12 boards ( SW trigger) then Ch2 on all 12 boards, then Ch3 etc.  I need to store ALL this data then process it ( post process?)  after acquiring all 900 chs.  Any suggestions or examples ?  In post processing how does LV distinguish between the raw data from Ch1 board 0 and ch 2 board 0 or even ch1 board 1 ?
Make my day and answer this question.
Thanks,
Clint E.

Answer 1

Clint,
In order to do this, you will need 12 individual tasks. Since you have
12 of these, I'm assuming that you have them inside of a PXI chassis.
The attached example is for 2 devices, but you can extend it to more by
repeating the bottom half of the code. You should physically locate the
master device (the one with the reference clock being exported) in slot
2 of your PXI chassis (the source of the star timing). In this code,
all other devices are synchronized with the master device reference
clock. Whenever the master's Start Task VI is called, this will assert
the AI Start Trigger signal on the master device, and all other devices
will use that as a digital trigger to begin their acquisitions. Please
make sure that all other devices execute their Start Task before the
master does (Merge Errors VI would be helpful). This process will
result in each of your devices acquiring samples at the exact same
time. The output of each analog read will output an array of waveforms,
with each waveform corresponding to the samples acquired on a single
channel of that device. To specify the order with which the channels
are scanned, order them that way in the physical channel control. For
instance Dev1/ai1,Dev2/ai3, Dev1/ai5 will acquire one sample from
channel 1, channel 3, and channel 5, then repeat. Please let me know if
this is not what you were asking, or if you have any additional
questions.
Hope this helps,
Message Edited by Voltage Viper on 12-02-2005 12:13 PM
Ryan Verret
Product Marketing Engineer
Signal Generators
National Instruments
Attachments:
M Series Multi-Device Synch - Shared Ref CLK.vi ‏60 KB