Synchronizing 4 SCXI-1140 Modules

[Pakman]

Hi avasque2,

The waveform enable control is an array of Boolean controls.  To create it, right click on the front panel and select Array & Cluster » Array.  Drop that down, and then place a Boolean control inside.  Then, right click on the array indicator on the block diagram and select Change to Control.  Do you have any other questions?

[avasque2]

I am getting error 1055 at property node.  Object reference is invalid. 

[Pakman]

Hi avasque2,

Try the attached LabVIEW 7.0 Express VI.  Also, make sure the task wired into the task property node is setup for your system.

[avasque2]

I used your design to get the module channels displayed but when I add my 4 module synchronization code they no longer stay synced.  I f I remove the 4 while loops they stay synced but then I can't choose any channels for more than one iteration.  How would I go about displaying all the channels and staying synced at the same time.  I also would like to be able to record all the data into an .lvm file or preferrably .xls.  Thank you for your time.

Message Edited by avasque2 on 06-23-2008 10:47 AM

[Pakman]

Hi avasque2,

First, remove the WHILE loop that you've placed around the whole application.  If you want to acquire samples continuously, change the Sample Clock's sample mode from Finite to Continuous.  Then, remove the four WHILE loops and replace them with one WHILE loop encompassing all the DAQmx Reads.  Finally, repeat the process with the FOR loops so that you only have one (keep the four separate arrays and property nodes, however).  Does that solve the synchronization issue?

As for writing to an .lvm or .xls file, it's probably best to feed each 1-D Waveform from the DAQmx Reads into four Convert to Dynamic Data Express VIs.  Then, feed those four signals into the Merge Signals Express VI.  Finally, wire the combined signal into a Write to Measurement File Express VI and write the data to an .lvm file.

Let me know if you have any other questions.


Message Edited by Pakman on 06-25-2008 11:18 AM