Apparent Drop-outs in Tcal Data Stream

Status:

Open date: June 1, 2004
Close date:

Participants:

John Jacobsen, Jim Braun

Symptoms:

Inconsistent TCal data from DOR card. Dead spots in the stream of TCal data lasting around 1 second or so.

Approach:

The programmer bag of tricks.
Check for continuity of TCal on the line.

Solution:

TBD

Summary:

TBD

Other supporting information:

Hi Jim,

Thanks for the report. I will see if I can see the large delta-t values with my domapp test, domapptest.c (in dor-driver/driver, if you want to try it yourself). Unless this is a high priority item I would prefer to wait until all the newpkt communications problems are solved.

Cheers,

John

Jim Braun wrote:

Hello icebuggers, particularly John J,

I've implemented a new test in my datacollector output verification routine which examines the delta-T between hit records. Looking at CPU triggered events, I see two distinctly different 'dead' periods in data between the usual ~400us spaced CPU events. First, I observe regular pauses of ~40ms which are presumably caused by buffer readout, and we know this time should be dead. Also, I observe much larger irregular pauses. These pauses are infrequent ( roughly 5% of 40ms pause rate ) and can range to slightly over a second in duration.

Here is an example:

( Units in 10^-10 seconds )

d893596f5ab1: Significant lag: 415169330 time: 5443370105623697

d893596f5ab1: Significant lag: 417093828 time: 5443370795107249

d893596f5ab1: Significant lag: 413047083 time: 5443371480680556

d893596f5ab1: Significant lag: 412592583 time: 5443372164431364

d893596f5ab1: Significant lag: 416565078 time: 5443372852289668

d893596f5ab1: Significant lag: 416736329 time: 5443373541751471

d893596f5ab1: Significant lag: 412734332 time: 5443374226352528

d893596f5ab1: Significant lag: 422602822 time: 5443374921198325

d893596f5ab1: Significant lag: 412013333 time: 5443375605539383

d893596f5ab1: Significant lag: 410899584 time: 5443376288425191

*d893596f5ab1: Significant lag: 7027859640 time: 5443383588635806*

d893596f5ab1: Significant lag: 414512831 time: 5443384275996861

d893596f5ab1: Significant lag: 418089827 time: 5443384965876163

Thanks,

Jim B