Sequoia LISST-Holo2, Руководство пользователя

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50 LISST-Holo2
User’s Guide
What is the maximum
sample rate for the
LISST-Holo2? The maximum sample rate for the LISST-Holo2 is 25 Hz (25 holograms per second).
Can I connect the
LISST-Holo2 directly
to the Ethernet port on
my PC? No.* You must connect via the supplied router or a local network. With the router, you can connect
wirelessly to your PC. If your PC does not have wireless capability you can plug the router into your
PC. However, in both circumstances the LISST-Holo2 must be plugged into the router and not the
PC.
*Exception: the Ethernet ports on most recent computers can support a direct connection, but you
would need to manually change your computer’s network settings so it occupies the same subnet as
the LISST-Holo2. Instructions for that are beyond the scope of this manual.
What is the maximum
concentration that the
LISST-Holo2 can be
used with? The concentration limits for a LISST-Holo2 are roughly as tabulated in the table below. See also this
article on Sequoia’s website:
http://www.sequoiasci.com/article/what-are-the-concentration-limits-for-
the-LISST-Holo2/ for a more thorough explanation.
The optional Path Reduction Module can be used to shorten the optical path which will allow up to a
factor of 5 increase in the maximum concentration.
Mean Particle Diameter Wentworth Grades Maximum
Concentration
[µm] [phi] [mg/l]
1.95 9.00 Clay 8
3.9 8.00 Very Fine Silt 15
7.8 7.00 Fine Silt 31
15.6 6.00 Medium Silt 62
31.25 5.00 Coarse Silt 123
62.5 4.00 Very Fine Sand 247
125 3.00 Fine Sand 494
250 2.00 Medium Sand 987
How do I tell if the
suspended sediment
concentration is too
high? If you cannot see any interference patterns (concentric rings) in the hologram, the concentration is
too high and you m
ost likely won’t get any sensible data out of the hologram when processing it. The
image on the left has visible concentric rings and will process well. The image on the right has too
many particles and will not produce good images of particles.
Why are my
holograms completely
black or white? Dark or saturated holograms may be cause by incorrect laser and camera settings on the
instrument. On the ‘Tools’ page of the web interface, select the ‘Set Defaults’ button to restore the
instrument settings back to the factory settings. Reboot the instrument and try collecting images
again. If the problem persists, contact Sequoia Scientific for further instruction.