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A – Operating Theory
DPN 402196 Issue 4.1
© Teledyne TSS
A- 1
A Operating Theory
The 440 System locates a target by:
1.
Inducing a pulse of current in the conductive material of the target.
2.
Using three independent coils to detect the magnetic fields associated with the currents
induced in the target.
3.
Calculating the position of the target from the relative strengths of the signals on each channel.
The Pulse Induction method of target detection, used by the Teledyne TSS 440 System, provides
considerable advantages over alternative magnetometer-based systems:
❐
Pulse induction can detect almost any type of conductive material – not just ferrous metals.
❐
Terrestrial magnetism has no effect upon the measurements.
❐
The System can compensate electronically for the proximity of the ROV body, regardless of its
magnetic heading.
❐
The System uses a simplified scaling procedure that allows a high degree of measurement
accuracy and stability.
This appendix describes the technique of Pulse Induction, and the method used by the 440 System to
derive the signal strength and the target co-ordinates.
A.1 Pulse Induction
NOTE
Because of the special characteristics of 316 stainless steel, it is very difficult to
establish strong eddy currents in this material. For this reason, you would experi-
ence considerable difficulties in detecting targets made exclusively from 316 stain-
less steel.
A current flowing through any coil will create a surrounding magnetic field. The strength of that field at
any instant in time will be proportional to the instantaneous magnitude of current. If the current in the
coil changes, the strength of the magnetic field will vary in proportion to the changes in magnitude of
coil current.
These variations in magnetic field strength will induce voltages in conductive targets that lie near the
coil. The magnitude of eddy currents that flow in the target because of these induced voltages will
depend upon two factors:
❐
The electrical characteristics of the target material.
❐
The rate at which the current in the coil changes.
Any eddy currents flowing in the target material will produce magnetic fields of their own and these
‘secondary’ fields will induce a measurable voltage in the coil as they change.
The 440 System uses this principle to detect the presence of conductive material near the search-coils.
See
, which shows a single cycle of measurement on one channel:
Содержание 440
Страница 12: ...List of Figures x Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 16: ...Revision History xiv Teledyne TSS DPN 402196 Issue 4 1 1 0 Feb 19 2003 First Issue Issue No Date Details ...
Страница 18: ...Glossary xvi Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 24: ...1 Introduction 1 6 Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 32: ...2 System Overview 2 8 Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 66: ...4 Electrical Installation 4 20 Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 88: ...5 Operating Software 5 22 Teledyne TSS DPN 402196 Issue 4 1 Figure 5 10 Altimeter Test ...
Страница 144: ...6 Operating Procedure 6 40 Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 154: ...7 Operational Considerations 7 10 Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 164: ...8 System Specifications 8 10 Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 203: ...10 System Drawings DPN 402196 Issue 4 1 Teledyne TSS 10 17 Figure 10 15 SDC10 Dimensions ...
Страница 204: ...10 System Drawings 10 18 Teledyne TSS DPN 402196 Issue 4 1 Figure 10 16 400604 1 Power Supply Chassis Assembly ...
Страница 205: ...10 System Drawings DPN 402196 Issue 4 1 Teledyne TSS 10 19 Figure 10 17 400667 1 Main Chassis Assembly ...
Страница 206: ...10 System Drawings 10 20 Teledyne TSS DPN 402196 Issue 4 1 Figure 10 18 400667 2 Main Chassis Assembly ...
Страница 209: ...10 System Drawings DPN 402196 Issue 4 1 Teledyne TSS 10 23 Figure 10 21 400654 1 PSU Filter Assembly ...
Страница 210: ...10 System Drawings 10 24 Teledyne TSS DPN 402196 Issue 4 1 Figure 10 22 490232 1 Processor Pod Assembly ...
Страница 211: ...10 System Drawings DPN 402196 Issue 4 1 Teledyne TSS 10 25 Figure 10 23 490228 1 Power Supply Pod Assembly 110v version ...
Страница 212: ...10 System Drawings 10 26 Teledyne TSS DPN 402196 Issue 4 1 Figure 10 24 500045 1 Coil Mounting Frame ...
Страница 213: ...10 System Drawings DPN 402196 Issue 4 1 Teledyne TSS 10 27 Figure 10 25 B930892 1 Coil Assembly ...
Страница 214: ...10 System Drawings 10 28 Teledyne TSS DPN 402196 Issue 4 1 Figure 10 26 601004 1 Coil Cable Assembly ...
Страница 215: ...10 System Drawings DPN 402196 Issue 4 1 Teledyne TSS 10 29 Figure 10 27 B930473 1 PSU to ROV PWR COMMS Cable 3 0m ...
Страница 230: ...A Operating Theory A 12 Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 242: ...B Options B 12 Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 244: ...C Altimeter C 2 Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 246: ...D Reference D 2 Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 248: ...D Reference D 4 Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 250: ...D Reference D 6 Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 252: ...D Reference D 8 Teledyne TSS DPN 402196 Issue 4 1 ...
Страница 254: ...D Reference D 10 Teledyne TSS DPN 402196 Issue 4 1 ...