1 – Introduction
DPN 402197 Issue 7.1
© Teledyne Limited
1- 3
NOTE
Both topside computers have their own dedicated user manuals and these should
be referred to for specific information on installation, operation and maintenance.
During survey operations, the sub-sea installation measures the target co-ordinates. These are:
❐
The vertical range to the target (VRT)
❐
The lateral offset of the target relative to the centre of the coil array (LAT)
❐
The altitude (ALT) of the coil array above the seabed, and the depth of target cover (COV). To
make these measurements, the 350 system must receive altitude information from an altime-
ter. Alternatively, where the design of the ROV allows for a constant coil height, you may con-
figure the system with this information instead.
❐
The angle of skew (SKEW) between the target and the coil array.
❐
The forward range to the target (FWD) when you operate the system in its forward search
mode. You
must
supply altitude measurements to the system for this feature to operate.
The SEP performs the signal processing functions necessary to generate accurate survey data with no
need for additional processing by the topside computer.
Optionally, you may use the 350 system as part of a Dualtrack installation. In this mode, a single
topside computer controls the operation of the 350 system when its subsea components are connected
to a TSS 440 Pipe and Cable Survey System. Refer to
for instructions to connect and
configure the 350 system within a Dualtrack installation.
1.3 Principle of Operation
The 350 system uses an array of six identical sensing coils arranged in two coil triads to detect the
alternating magnetic fields that surround a tone-carrying cable. The directional characteristics of the
individual sensing coils in each triad enable the system to locate the relative position of the target
cable.
The method used by the 350 system to locate and survey the target cable is insensitive to the effects
of:
❐
Variations in the magnitude of tone current
❐
Terrestrial magnetism
❐
Burial condition of the target cable
❐
The presence of non-ferrous metallic objects in the search area
1.4 Warranty
Please refer to your sales agreement with Teledyne Limited for information about the terms and
duration of the warranty for this product.