Multi Device task Synchronization PXI 1078 pxi 6356 and PXI 4330 and PXI 4353

[barak]

Hi.

I am trying to configure in the express DAQ Assist a multi device task.

When defining a voltage(6356)  with thermocouples (4353) task it works (see pic 1)

When defining a voltage (6356)  with Strain Gages (4330)  task it not working (see pic 2 with error massage)

According the the white paper http://www.ni.com/white-paper/11369/en/  it should works because all  models support the multi device task.

The complete max setup is in pic 3.

The goal at the end us to have a multi device task for all 3 models.

[replyall_ia]

Hi,

Do you think can attach the code for the working system and the non working system? I'm curious to see if there is a caveat somewhere since the white paper does say the 4330 is supported. Just to double check, you have the PXIe-4330 right? I don't believe that we have a PXI form factor of that.

[barak]

Hi.

There is no code, just try it using the express daq assistance.

The white paper does says this modules can be sync but after continue reading NI divided the modules into 2 different groups,

• Sample clock timed devices
• Oversample clock timed device Based on the white paper there is no way to lock clocks for all modules if they are not in the same group. 
• This bring a very low sync performance to a PXI system with modules from different groups.
• Furthermore based on the white paper sync modules from different groups can be done by export clock (same sample rate!!!) or just using a start trigger from one group to the other that can result in a drift between moduls.
• Only devices from the same group can be used in a multi device task so the statement at the begging that all SC express modules can be used in a multi device task is conflict with this groups definition.

[replyall_ia]

Oh, I see. Also, yes, that sounds correct although the syn performance to a PXI System is actually great -- the caveat is that we need to reference the same hardware clock as opposed merely software clock. Using the trigger line on the device or even the 100MHz clock in the back should do it. As far as the sample rate is concerned, synchronizing them would require the same sample rate, unless you can manage to divide down the clock rate for each particular device from the master timebase.