Nanometrics TC120-PH1, Руководство пользователя

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Trillium Compact User Guide
16889R5

2014-03-04
10
Chapter 2
Performing a Posthole Installation
2.1 Installing a Trillium Compact Posthole
A Trillium Compact Posthole seismometer may be installed in an uncased or cased hole.
Units will self-level as long as the Trillium Compact Posthole is within ±2.5° for the 120 s model
or ±10° for the 20 s model of vertical, making site preparation simple.
Use the following steps to install a Trillium Compact Posthole in an uncased or cased hole:
1. Prepare the hole for the installation.
• Uncased hole
For an uncased hole, the hole should be a minimum of 1 m deep, and have a
diameter large enough to accommodate the seismometer, which has a diameter
of 97 mm. The minimum hole depth will allow the seismometer to be covered by
approximately 0.9 m (3 ft.) of fill once the installation is complete. This backfill
creates a buffer between the installation and the surface, shielding it from surface
activity and weather. In general, greater depth produces better results with all
other conditions being equal.
• Cased hole
For a cased hole, the hole diameter must be large enough to accommodate the
seismometer, which has a diameter of 97 mm.
A cased hole must be covered at the top to protect the seismometer from the
elements such as wind and rain. This cover must secure and stabilize the electrical
and lifting cables, allowing some slack to avoid strain on the seismometer.
2. Connect the cable to the seismometer and digitizer.
Nanometrics cable 17768-nM (where n is the length of the cable in metres) can be
used to connect a Trillium Compact Posthole to a Nanometrics digitizer. Alternatively,
if you are connecting your Trillium Compact Posthole to a third-party digitizer, you can
connect the digitizer’s connector to Nanometrics cable 17356-nM (where n is the
length of the cable in metres), or contact Nanometrics to inquire about the availability
of a cable for a specific digitizer (see Contacting Nanometrics on page 81).
See Chapter 5 , “Configuring Your System” for information on configuring your
Nanometrics digitizer for a Trillium Compact Posthole and also refer to the digitizer
manual.
(1) The contents of this chapter are applicable to Trillium Compact, model numbers TC120-PH2
and TC20-PH2, TC120-PH1, and TC20-PH1.
(2) For model numbers TC120-PH1 and TC20-PH1, the cable waterproof shroud will be required
to bring the unit to an IP68 rating for full submersion. See Table 1-1 “List of cables and
accessories” on page 4. See Appendix B , “Cable Waterproof Shroud” for details on how to
install and use this cable assembly.