NI High Speed Digitzer - First acquistion is always delayed by a few ms

[asukumari]

The NI 5160 High Speed Digitizer has a warmup time of 15 mins according to the specification sheet. This I assume means that the chassis in which the digitizer resides should be ON and going for > 15 mins. Only after this period, it is recommended to use it.

Now, even after waiting out the warmup period, the first acquisition seems to be delayed (~3ms to 4ms) than the rest. My application depends on precise timing and if the first one is delayed then it is a problem. Is this an inherent nature of digitizers? Why does this happen, and how to handle this? Any advise on this is appreciated.

This happens only on the very first acquisition and the rest that follow are perfect.

[iradovanovic]

asukumari, 

That is correct! The warm up time is that the chassis with the card inside should be running for 15 mins. Looking through the manual, it mentioned a software self-calibration after the warm up time. Do you get the same behavior after doing this?

How long have you had the card for? The recommended external calibration should be done every 2 years. 

Hope this helps! 

[Henrik_Volkers]

We don't know how you setup the scope..

When I

• do all configuration (Clk10 or 100 backplane based)
• send a commit
• sync the cards
• arm the trigger

   and use hardware trigger  I have never seen such delay.