Geometrics G-877, Operation Manual

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2.2.2 Tow
Cable
The tow cable is a polyurethane jacketed Kevlar reinforced 5 conductor cable with a breaking
strength of 6,000 lbs and an operating load of 1000 lbs. The clevis and Subconn connector on
the fish end has been described above. There is a male Bendix type connector on the other end
of the tow cable for attachment to the Junction Box. (Note that for long cables, an On-Board
Cable may be supplied, see below).
The cable is perhaps the most vulnerable part of the system and that part subjected to the greatest
physical abuse. Geometrics offers retermination kits for those instances when the cable has been
damaged due to contact with obstructions, coral or the sea floor.
2.2.3 Junction
Box
There is a 9 pin RS-232 connector on the Junction Box for a standard serial cable (supplied)
which connects to the Logging Computer serial port. In addition there are connections to power
and to the tow cable. It is IMPORTANT that the grounding lug be attached to a wire that will
then be grounded to sea water using a lead or steel weight to make sure the system is grounded at
this single point only. The ground is islolated for direct current.
An On/Off switch applies power to the magnetometer. If the DC power cable is connected to
reversed DC power, the LED will light Red. Normal operation is with the Green light lit.
It is imperative that you read the introductory and operation parts of this manual in their
entirety prior to system assembly and initialization.
Also, it is important to read the
MagLogLite

Software Manual.
2.2.4 Logging Software and Hardware
The system is typically shipped with a logging, display and communications logging software
package called
MagLogLite

. High-speed playback of the survey data on the computer screen
is available using MagLogLite

(see software manual). Alternately, such software packages as
Coastal Oceanographics Hypack or Triton Elics ISIS or EIVA’s NaviPak offer logging and
display capabilities. However, any terminal emulator program such as Windows Hyperterminal
may be used for direct communication with the G–877, though not for logging of GPS
simultaneously or displaying the data or running real-time diagnostics. Hyperterminal is handy
when troubleshooting computer serial port or communications difficulties.
The Logging Computer may be customer or Geometrics supplied. In general it should be a high
performance Desktop or Laptop computer (PII 500MHz or better) with either Windows 98, ME
12 G–877 MARINE MAGNETOMETER OPERATION MANUAL