TSHD - Dredging Sensor

Dredging Sensor Definition

Prior to defining a dredging system the observations that support the dredging system should be defined (usually part of a dredging sensor system type). For example the dredging status (e.g. dumping/dredging/sailing loaded), current measurement, open/close bay door observation etc.
Note that this is optional, all the values can also be entered/overruled online.

Observations associated with a Dredging Sensor are:

Density (of mixture)
Velocity (of mixture)
Weight (displacement)
Volume
Hopper Level
Dredging Status
Flag (e.g. PMO valve)

In addition to the various predefined drivers provided, the IO Editor may be used to write a driver to decode a currently unsupported data string.

The Dredging Sensor system works in conjunction with

a USBL System to decode drag head positions
an Underwater System driver decoding vessel draft (fore and aft),
a Miscellaneous System to define such observations as Solid Density, Water Density, Trim tank total. This driver also computes TDS
and the Dredging System where the dredger type is selected, density/velocity sensors are enabled, TDS and PMO calculations are enabled, nodes are allocated and observations are assigned.

To define a Dredging Sensor:

Add a new system by selecting “Edit” from the menu bar, and then “New” and “System”, or right click on the item System in the item tree.

The following dialog opens. It is the first page of a wizard that steps you through the system definition process.

Enter an appropriate name that provides instant recognition in Online displays.

Select Dredging Sensor from the drop down list.

From the drop down list select the driver that corresponds to the data message output by the system to which Qinsy is interfaced.

If there is no existing driver, this could also be a driver created with the IO Editor

Note that the interfacing can be either serial or network so make sure to select the correct type.

Enter interface port parameters.

Please refer to A Note on Interfacing Parameters.

Enter the data update parameters. Depending on the driver selected one or other, or both, these parameters are shown:

Updates

Maximum update rate

Enter a value to determine how often data will be decoded by the interface driver. Some equipment is capable of outputting data at high output rates, but it may not be necessary to use each update.
A sensor system may for example output values hundreds of times per second, where five times per second is sufficient. In this case, enter a value of 0.20s. Any data not decoded by the driver is lost and cannot be recovered later.

Latency

Latency is the time between the actual measurement made in the sensor system and the time the data message arrives at the port. The time in Qinsy will thus be the arrival time corrected with the latency.
Modern sensor systems will exhibit no latency, or will have compensated for the latency in the time tag of each data message.

Press Next to advance to the second page of the wizard which will look like this:

Initially the dialog is empty. Select the object upon which the sensor is located. In this case it does not really matter so select the primary object.

Click on the Add button which brings up the Define Observation dialog.

Select the type of observation that is to be read from the sensor. Then enter an observation name.

Select a node at which the sensor observation is made.

Click OK to return to the Observation Definition dialog.

Click on Edit Slot and enter a numeric, alphabetic or alphanumeric identifier.

This slot ID must match the identification associated with the parameter in the data message received from the sensor. In this case 'Density' is the identification used in the data message that differentiates the density data field from all other data fields in the message.
Refer to the Drivers & Interfacing Manual for information on fields decoded and slot identifiers to use.

Repeat the process by clicking on Add to define other observations that will be decoded from the data message received from the sensor.

In many cases the data message will not include all of these observations.

Click Next to advance to the wizard's third page.

Observations add on the previous page of the wizard are listed. Click on each observation in turn and enter values for its associated parameters.

Observation parameters
Name	Enter a descriptive name for the observation.
Unit	Select the appropriate observation unit. In some cases there will only be one choice.
a-priori SD	Enter the SD for each observation in turn.
Fixed C-O	Constant correction to the parameter value.
Variable C-O	Variable correction to the parameter value.
Scale factor	Use scale factor to convert the raw output to units in the Acquisition Software. For example if local output is in centimeters, then enter scale factor 0.01 here to convert to meters.

Click on Finish to complete the sensor definition.

Return to 43507500.

Return to: Trailing Suction Hopper Dredger (TSHD) - System Definitions