Geometrics G-877, Operation Manual

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2.0 G–877 SYSTEM DESCRIPTION, INSTALLATION AND
COMMISSIONING
2.1 SYSTEM OVERVIEW
The G–877 Magnetometer consists of 4 main assemblies. These are the Magnetometer Fish, the
Tow Cable, the Junction Box/Power Supply and MagLogLite™ Logging and Display Software.
2.2
DETAILED SYSTEM DESCRIPTION
The G–877 is a digital magnetometer. This means that it communicates via an RS-232 from the
magnetometer fish to the computer serial port (i.e., Com 1) via the tow cable, junction box and
RS-232 cable. The tow cable employs 5 wire cable (5 conductors), two for power and three for
RS-232 communications. On the deck the G–877 is supplied with an AC/DC Junction Box
which provides connections for tow cable, RS-232 and power (see photo below). Power is
supplied from either an AC Power supply or user supplied DC battery power with supplied
clamp cable. The AC Power Supply is a 120/240 VAC to 28volt DC supply which connects to
the ship’s AC mains. The DC input cable provides for operation from a 24 - 32 volt DC source
such as 2 car batteries wired in series. Software to log and display digital magnetic data is
available from Geometrics and may be included in your purchase.
The G–877 Marine Proton Magnetometer system may include the following
assemblies/modules: Logging and Display Computer (optional, may be customer supplied), Dot
Matrix or Printrex Thermal Printer (optional), AC Power Supply, Junction Box, On-board cable
(optional - runs from the instrument room to the stern mounted winch if required), G
−
877 Sensor
Tow cable and Magnetometer Fish. The Logging and Display Computer should provide two
communication ports, one for the Magnetometer input and one for the customer or Geometrics
supplied GPS unit. It should be noted that the positional accuracy of the survey data will be
determined to a large part on the accuracy of the GPS employed. The use of a Dot Matrix
graphics printer is optional but does afford the user a permanent record of the survey. The
system requires 115 or
220 VAC, 50/60 Hz at 150 watts or 24-32 VDC at 2 amps
G–877 MARINE MAGNETOMETER OPERATION MANUAL
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