[RASMB] Data acquisition failure

[Tom Laue]

Hi Christine-
This error occurs when the radial servo motor takes too long to reach a 
position. Sometimes it is caused by a sticking slit positioner, leading 
to non-reproducible scans. That does not appear to be the case for this 
experiment since the meniscus spikes are aligned.
It may be that the servo broke suddenly, or it may be that the readings 
from the servo were abnormally noisy, leading to this error.
In any case, I would suggest that you have the service engineer check 
out the radial slit positioning system to make sure it is ok.
Best wishes,
Tom

Christine.Wandrey at epfl.ch wrote:
> Dear all,
>
> during our last overnight run (absorbance, 200 scans) a data 
> acquisition failure occurred.
> Message: "DAB: Radial rate failure"
>
> From single scans I could identify that the failure happened at scans 
> 133. Scans 1-132 look normal. These early scans fit well together. 
> Starting with scans 133 a much wider radial range was monitored in the 
> set range 5.9-7.2. It seems that a range of about 5.7 (cell material) 
> to 7.3 ( also cell material) was monitored later.
>
> My question: Does this failure occur suddenly or could the earlier 
> scans already be affected?
>
> Please find attached a pdf file, which demonstrates the scans before 
> and after the failure. Note, that the sedimentation process was 
> already finished when the failure occurred.
>
> Thank you.
> With kind regards,
> Christine
>
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-- 
Department of Biochemistry and Molecular Biology
University of New Hampshire
Durham, NH 03824-3544
Phone: 603-862-2459
FAX:   603-862-0031
E-mail: Tom.Laue at unh.edu
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