Dynamic Signal Acquisition

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Synchronizing multiple PXI-4472 boards installed in 2 PXI-1000 chassis


I need to acquire 64 channels of data, and I plan to use 8 x PXI-4472 boards installed in 2 PXI-1000 chassis. The data acquisition process has to be synchronized for all the channels. I found the example "Using LabVIEW to Synchronize Multiple NI PXI-4472 Devices and Stream to Disk - Example - Development" of great help to setup the different cards in one chassis synchronized (using one route signal VI to route the board clock of the Master Device to PXI Star, and then using a number of route signals VIs for each slave device to route the clock from PXI star to the board clock). However, I am not sure how to synchronize the 4472's on the second chassis. Do I need to use 2 PXI-6653s, one in each chassis, and put the 6653 in the master board (slot 2) of the second chassis? Also, what changes are required in the block diagram in LabView? More specifically, how are the devices and slots in the second chassis addressed?

Many thanks,
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Ben -

Here is a good KB that describes where to go for me information of multichassis synchronization (KB 2WF8F22L).

Here's a quick overview:
You will need a 6652/3 in slot 2 of the master chassis and a 665x in slot 2 of the slave chassis. The master 6652/3 will generate all of your timing signals to both the master and slave chassis. The slave 665x routes all the signals to the appropriate line on the PXI backplane.

Your two chassis may be connected by MXI-3/4 or they might both have a controller in them. In the case where you are using MXI, everything will show up in MAX like they already do and that is how you will address them. The 665x boards use a different drvier, called NI-SYNC which you will need to download as well.

I've attached some sample code which will synchronize boards in two chassis using DAQmx. Hopefully you'll find this a good place to start on the LabVIEW side.

Message 2 of 5
thanks for your useful reply.

Is it possible to send the sample code in Labview 7.0 format rather than 7.1.1?

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Ben -

I just re-read you initial post. Are you just using 8 PXI-4472s? If so, the easiest thing to do would be to get a 14-slot PXI chassis like the PXI-1044. Then you would not need the 665x boards or MXI. Something to think about.

I've also attached a 7.0 version of the code below.

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Thanks Jack!

Yes a 14-slot chassis would have definitely made life easier. I'll try to persuade the boss to put his hand in his pocket...but I have a feeling I have to stick with what I have! 🙂

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