Teledyne 440, System Manual, Page: 152 / 256

7 – Operational Considerations
7-8 © Teledyne TSS DPN 402196 Issue 4.1
NOTE
Remember that the 440 System detects the presence of any conductive material
nearby. When you install the System on an ROV therefore, avoid the presence of
any conductive material within range of the search-coils.
During a survey, you must avoid using any manipulator arms, probes, or other
items that can move while you are operating the 440 System. To guarantee the
accuracy of your data throughout the survey, you must perform regular checks on
background compensation.
7.3.1 Speed of Operation
The 440 System delivers measurements to a data logger continuously at a rate that allows deployment
on faster ROVs. This is sufficient to maintain a high track resolution under all normal operating
conditions.
7.3.2 Altitude above the Seabed
The vertical detection range of the 440 System is limited by the characteristics of the target, in
particular its size.
The low signal strength that the System receives from a small target will reduce its detection range. If
you use the System to survey a small target you should therefore operate the ROV as near as possible
to the seabed, while avoiding damage. If your ROV has an automatic facility for maintaining altitude,
you may use it.
Larger targets will cause stronger signals in the search-coils so that you may operate the ROV at a
greater altitude above the seabed.
7.3.3 Manipulators and Probes
Any manipulators or probes deployed on the ROV during a survey will present moving targets that the
440 System will detect. These movements might therefore introduce errors to the survey
measurements.
You should avoid using such tools during a survey unless circumstances demand their deployment.