DAQmx example "Multi-Device Synch-Analog Input-Finite Acquisition.vi"

[bmann2000]

I'd like to sync 72-channels across nine 6123 cards.  The example quoted above demonstrates how to sync 2 individual channels on 2-cards.

Other cards e.g. 6561, niHSDIO VIs have examples for Multi-Device that include FOR loop initialisation for Multi-Device synchronisation.  Is there equivalent example code for Multi-Device synchronisation of the 6123 cards ?

[DanBrowne]

Hi bmann2000,

Can you attach the specific example (containing the For loop initialisations) that you are looking at - it may be that a relatively simple modification is all that is needed to use it with your card.

Regards,

Dan - NIUK

[bmann2000]

Is the hardware on the 6561 significantly different from the 6123 ?   Can TClk be used with the 6123 ?

Attached are screendumps of the example code shipped with LabVIEW 8.5.1.  At a glance it would appear several channels for the 6123 could be initialised by wrapping a FOR loop around the first VI, but it's not that straight forward.  I want to expand the example for 6123 for 72-channels, or find a cleaner alternative, e.g. like the code for the attached 6561.

[bmann2000]

This link answers the some of my questions on TClk http://zone.ni.com/reference/en-XX/help/370592G-01/nitclk/nitclk_overview/#SMC  Could TClk compatible drivers for 6123 be developed by NI at a future date? or is there something missing from the hardware of the 6123 to support TClk ?

I figure my question is simply, what is the best code example for synchronising 72-channels on nine 6123 cards ?

[Ryan_M]

Bmann,

The 656x and 6123 are architected very differently.  The 656x is built using SMC technology which enables TCLK synchronization.  Unfortunately, the 6123 does not support this feature.  You can use TCLK to synchronize all of your 656x's but will need to use traditional synchronization methods (such as PXI triggers) to synchronzie a 656x with a 6123.

[bmann2000]

The example to sync here, http://zone.ni.com/devzone/cda/tut/p/id/4322  is similar to the example shipped with LV8.5.1

for clarity, the code of the two examples as are added as .jpg's to the post.

Are both examples fundamentally doing the same thing ?  "Sharing a Master Timebase" from one of the 6123 cards, and "using PXI Star Trigger to Trigger all cards simultaneously" ? 

For 72-channels, would I need to create a huge diagram with 72 parallel paths ?

[bmann2000]

I've initialised the tasks using a FOR loop, but now struggling to read back all the data for longer acquisitions.  Please see this post for a copy of the VI in use.  http://forums.ni.com/ni/board/message?board.id=250&thread.id=44006