15
7.
OPERATING PRINCIPLES
7.1 GENERAL
A zero-setting procedure is always necessary in order to obtain a correct measurement and reading of
the T-Sense
®
Torque sensor or TT-Sense
®
Thrust & Torque sensor.
For more detailed information see section 6.4 of TIB-661 T-Sense
®
or TIB-664 TT-Sense
®
.
The SDB-3 and Bridge Panel PC is an integrated solution for monitoring shaft power and triggers audible
and visible alarm when the EEXI power limit is exceeded. The menu structure of the SDB-3 and Bridge
Panel PC is self-explanatory, and the system is easy to operate.
Several conditional messages will inform you about error/fault conditions if applicable.
Setups determining functionality are subdivided in two levels and access is only possible via a right-of-
access code. All setups and computations are stored in a battery backup RAM. The SDB-3 and Bridge
Panel PC system is self-explanatory as for correct functioning of its memories, program run and existence
of supply voltage.
7.2 DISPLAYED PARAMETER AND ENGINEERING UNITS
The following parameters are available
Unit
•
Shaft torque
kNm
•
Shaft speed
rpm
•
Shaft power
kW
•
Time-base
Year, month, day, hour, minute, second
•
GPS NMEA Ship
’s SOG (Speed Over Ground)
knots
•
GPS NMEA Ship
’s STW (Speed Through Water) knots
7.3 EXPLANATION OF PARAMETERS
7.3.1 Shaft torque
The shaft torque is measured in the T(T)-Sense
®
rotor part and sent wireless to the stator control box.
The shaft torque output of the stator control box is connected to SDB-3 via RS485 Modbus. When a 3
rd
party Torque meter is connected to the SDB-3, the shaft torque output of the Torque meter is connected
to the SDB-3 via a 4-20mA analog connection.
7.3.2 Shaft speed
The shaft speed is measured via a gravity sensor in the T(T)-Sense
®
rotor part and sent wireless to the
stator control box. The shaft speed output of the stator control box is connected to SDB-3 via RS485
Modbus.
When a 3
rd
party Torque meter is connected to the SDB-3, the shaft speed output of the Torque meter is
connected to the SDB-3 via a 4-20mA analog connection. When multiple Torque sensors are connected
to the SDB-3, the shaft speed of Torque meter one displayed in the Bridge Panel PC.
7.3.3 Shaft power
The measured torque and shaft speed are the input values to the power calculation, which is performed
in the T(T)-Sense
®
stator control box. The shaft power output of the stator control box is connected to
SDB-3 via RS485 Modbus.
When a 3
rd
party Torque meter is connected to the SDB-3, the shaft power output of the Torque meter is
connected to the SDB-3 via a 4-20mA analog connection.
When two Power sensors are connected to the SDB-3, the shaft power from engine 1 and the shaft
power of engine 2 are summed together.