VAF instruments 667 - Speed over Ground (SOG) Via NMEA0183; Speed through Water (STW) Via NMEA0183; Speed through Water (STW) Via Pulse Signal from Speed Log; Density

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7.3.8 Speed over ground (SOG) via NMEA0183
A GPS signal can be connected to the SPU3 through the RS422 port (J4).
The ship’s speed over ground is hidden in the NMEA0183 protocol. The PEM4 + SPU3 system will read
out the $--VTG sentence (“speed over ground”) and the value will be displayed in knots.
No adjustments are needed. ***)
7.3.9 Speed through water (STW) via NMEA0183
A GPS signal can be connected to the SPU3 through the RS422 port (J4).
The ship’s speed through water is hidden in the NMEA0183 protocol. The PEM4 + SPU3 system will
read out the $--VBW sentence (“longitudinal water speed”) and the value will be displayed in knots.
No adjustments are needed. ***)
7.3.10 Speed through water (STW) via pulse signal from speed log
In case the ship’s speed is measured with a (Doppler) speed log, the pulse output signal from the speed
log’s potential free contact is transmitted to the SPU3 through the speed log input (J6).
The ship’s speed range is programmed at VAF location or can be set via the settings menu by VAF
authorised representatives through the PEM4 touch screen.
The default setting is 200 pulses/nautical mile. ***)
***) The speed which is displayed and used for calculations is depending on the settings and
availability of the signal to the input.
STW-NMEA is 1
st
choice, STW-Speed log is 2
nd
choice and SOG-NMEA is 3
rd
choice.
-
For example in the situation that “NMEA”, “NMEA STW” and “Speed log” are selected as “Enable”
in the PEM4 settings menu and their signals are available on the inputs. In this situation the PEM4
+ SPU3 system will use STW to display and use for calculations. In case the STW signal is not
available, the PEM4 + SPU3 system will automatically use speed log.
7.3.11 Density
A maximum of 6 ViscoSense
®
3D systems can be connected to the SPU3 system. The density and
temperature signals are connected to the SPU3 through analogue 4-20mA signals.
Using density the mass flow and mass consumption can be calculated.
7.3.12 Draft
The draft front, middle SB, middle PS and at the back can be connected to the SPU3 through 3 analogue
4-20mA signals.
7.3.13 Inclino
By use of an inclinometer the pitch, roll and yaw can be connected to the SPU3 through 3 analogue 4-
20mA signals.
Note: The maximum number of analogue inputs is 9 inputs, depending on the system
configuration.