Page 297 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

11.1 Vehicle sensors 287
Table 11.1 Housekeeping Sensors by ROV Classification
Sensor OCROV MSROV WCROV
Single channel video Compass
Depth gauge
Tether turn counter Rate gyro
Lighting level adjustment Ground fault interrupt Multiple channel video Camera pan and tilt Camera zoom/focus Motor current draw Tether in/out
X X X X X X X X X X X X X X X X X X X X X
X X X X X X X X X X X X X X X X X X X X X X
X X X X X X X X
Water ingress alarm
Ground fault interrupt by circuit Obstacle avoidance sonar Altimeter
Low oil level warning
Valve pack control sensors
Oil temperature sensor Compensator oil level
Lighting adjustment by
System diagnostics
System oil pressure by Inclinometer for vehicle Integrated INS/DVL for Multiaxis slaved gyro
light
circuit (mains/aux) pitch/roll/yaw/trim dynamic positioning
derived, thus registering the measurement at the cardinal headings and orientations. This is the the- ory of operation of a simple flux gate compass. The most popular of the flux gate compasses used today in ROV applications is the PNI TCM2 series of sensors. For further details, visit their web site for technical specifications.
11.1.1.2 Tether turn counter
Tether turn counters are not technically considered sensors. The turn counter is a register within the vehicle’s CPU that accepts digital heading readings from the compass and counts the number of times the vehicle turns based upon those readings. It is best to bring the tether turn count back (or near) to zero before recovering the vehicle to the surface.