CompactRIO RT freeze when I use "Set Time.vi"

Question

I'm using a compactRIO and need to update the internal time of the device to be clock synchronized with my whole system. Everything seemed to work perfectly but when I try to apply an offset between 0 and -30 seconds, my compactRIO freeze. Nothing happen if I apply a positive offset or an offset "higher" (in a negative way) than -30 sec.
The duration of the freeze equals the offset I apply on my device and after this delay, everything comes back to normal. The freeze affects all my RT code (other processus as well) and not only the VI where I use the "Set Time.vi". The FPGA seems to be working during the freeze time because I got "DMA is full" error after the freeze and the FPGA LEDs keep blinking during the whole time (on the contrary the RT LED stop blinking).
Has any of you already noted something similar on compactRIO 9068 (Linux) ? Or do you have any idea of what is going on ?
Thanks for you help.
Nicolas
Additionnal informations :
   - LabVIEW 2013 SP1
   - NI RIO 14.0.1
   - CompactRIO 9068
   - Linux Embedded
   - LavBIEW Real-Time 13.0.1
PS :
- I use regular loops, no absolute timing VIs only tick count or nothing.
- The freeze happens in interactive mode but also with an rtexe.
- The compactRIO stays connected during the freeze.

Answer 1

Guillaume.D a écrit :
Hello,
I'm not surprised by this behavior : the VI "set the time" define the absolut timing (hour and date) for the target : tha changes which are applied at this VI are applied at all the process ans task of the target.
The FPGA of the CompactRIO is not impacted by this : in your VI, you define "localhost" wich corresponded at the RT part of the cRIO system.
The FPGA continue to work separately of the RT part.
I agree that Set Time VI affects the whole RT code but what I don't understand is why "untimed loop" or "timed loop with internal 1 kHz clock source" (no absolute time) are affected by the absolute time shift.
The behavior doesn't happen on VxWorks target.
Int he most application, you use the VI  "Set the time" to define the absolut time at the initialization, and after you don't modify it.
I'm developing a continuous compactRIO data logger which (I hope ^^) should never stop even after hours / days / months of running. I have noticed a drift of 1.5 sec / day on my compactRIO so I must need to resynchronize it all the time.