DQRID : D141216.3
Start DateStart TimeEnd DateEnd Time Data Quality Metric
02/17/2014145507/25/20161805Suspect
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Subject:
ENA/UHSAS/C1 - Problem with time fields
DataStreams:enaaosuhsasC1.a1
Description:
During the ENA deployment, the UHSAS instrument clock was not synced with a time server. I 
used a comparison of the peaks in the UHSAS data and the CPC or the PSAP data to 
determine how far off the clock was.  The UHSAS was always within ~2 minutes of the other 
instruments and the CPU it was attached to.  Starting from 2/18/2014 the UHSAS was ~ 45 
seconds. slow.  It gradually got faster and around 6/2014 it was within seconds of the CPC.  It 
continued in that direction and gradually became slower than the CPC or PSAP.  On 
1/22/2015 the UHSAS was ~120 seconds slower than the PSAP.  At 16:05:00 1/22/2015 the UHSAS time 
was manually set to the Unit 2 CPU time.  This was done remotely and apparantly only to 
within about 20 seconds.  

A  Document  shows the times of the peaks used to determine the time 
difference. 

During 2015 until the Domain time II was installed on 07/25/2016 the UHSAS was synced 
manually about once a month.  Between syncs it generally drifted slow.  During the period 
until 06/24/2015 the monthly correction was less than 20 seconds.  There was a gap in the 
corrections and on 10/21/2015 it was corrected from 1 minute 22 seconds slow.  The 
corrections after that were from about 15 to 35 seconds slow.  The first time sync after Domain 
time II was installed corrected the time from 1 minute 12 seconds slow.
Suggestions: 
Average data for longer periods. Compare peaks with other instruments to calculate 

how far off the time was.
Measurements:enaaosuhsasC1.a1:
  • auxiliary
  • unit_temperature
  • scattering_voltage
  • lower_size_limit
  • current
  • size_distribution
  • time
  • reference
  • flow
  • differential_voltage
  • sample_pressure
  • upper_size_limit
  • sheath_flow
  • base_time
  • purge_flow
  • bin_num
  • sampling_volume
  • time_offset
  • temperature
more

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