4472 synchronization

[SreedharT]

Hi all,

I am using 4 modules of PXI 4472 on an PXI 1010 chassis. I have configured them in the RT mode and acquiring data remotely. My problem is I am unable to synchronize all these 4 cards. I am getting proper data from the master 4472 but only junk data from the slaves. As the convension says, I have put master in slot 2 and the slaves are in 3, 4 and 5 respectively.
I am sure there is some problem with the clock sync or trigger. Please help.

I am also attaching the VI that I have followed.

[chericks1]

Hi SreedharT,

Synchronization is now much easier with NI-DAQ 7.4, and I recommend upgrading to this driver for your application. We found customers often had problems attempting to use Traditional DAQ to synchronize their DSA devices, so we decided to include this functionality in the NI-DAQ driver. Channel expansion is the feature, and all that's required is to include the device descriptors and channels from which you are interested in acquiring.

I've included for an example a program shipped with NI-DAQ called Acq&Graph Voltage-Int Clk.vi. The only alteration I made to it was the Physical Channel name where I included all the devices and all the channels of interest. That's all you need to do. The driver will do the rest!

Let me know if you have further questions or this does not resolve your issue!

Chad AE
Applications Engineer

[SreedharT]

Hi Chad,

I have tried using a similar example that is there in NI Example finder>DAQ MX>synchronization>multi device.dll. but I was not successful either. In this program, Where will the ICP excitation come from in this case? The sensors that I am using are acclerometers. Anyway I will try using this example also.

One more thing that I want to bring to your notice is that, while using my example that I have attached above, if I am enabling all the channels of all the four cards then I am getting signals from the first three, i.e. master (slot 2), slave 1 (slot 3) and slave 2 (slot 4) but NOT from slave 3 (slot 5). Similarly, if I am enabling the channels of only 3 cards (master, slave 1 and slave 2), then I am acquiring signals from only 2 cards (i.e master and slave 1). This pattern is continuing if I am putting only 2 cards also (i.e I am getting signals from master only). It will be of great help if you can go thru the program that I have attached once again and tell me if there is any programming mistake.

Thanks a lot in advance.

[chericks1]

Hi Sreedhar T,

I looked over your code, and nothing looks wrong. I've ran it and it works for me. When you say you are enabling all four cards, and receiving signals from three, does that mean the fourth card returns nothing, or does the fourth card return trash data. If this is the case, I'm confused at what could cause the issue.

In any case, why again can you not use a DAQmx program such as the following?

Cont Acq Accel Samples-Int Clk-Analog Start.vi
Open Example Finder, expand Hardware Input and Output->DAQmx->Analog Measurements->Acceleration

This program, when used with DAQmx 7.4 will automatically synchronize all the DSA devices. The only steps you need to take are to right-click on the Physical Channel input and select I/O Name Filtering... Then confirm that Allow Undefined Names is checked. Then, you'll be able to enter all the boards and all the channels you need, i.e.

Dev1/ai0:7, Dev2/ai1:4, Dev3/ai0, Dev4/ai0:7

Let me know how things are going!

Chad AE
Applications Engineer