Meta Items
Meta items are atomic pieces of data. The heart of each meta-item is its value, which is written to data files or monitored by the Logger during an event.
All Meta Items are updated via an action inside an Action Sequence.
Date Time
A Date Time Meta Item represents a Date and Time. When updated it gets it's value from the SCS Server's local system clock. As with timestamps throughout SCS it's value is in UTC.
The only option to set for a Date Time Meta Item is the Label. Most things in Events are time stamped independent of any Meta Item, however if you want to note the time on the UI when something last occurred this can provide a means of doing so.
See Also: Action Sequences - Meta Item Update
Sensor
A Sensor Meta Item gets it's value from a sensor being acquired by the SCS Acquisition Service. When updated it will get the latest value and store/display it.
The Label for a Sensor Meta Item can be something you type yourself or you can link it to the sensor feed supplying the data by checking the Sync Label to Data Item's Name checkbox.
Click the Select Source button to set the sensor feed you wish to associate with this component
See Also: Action Sequences - Meta Item Update
Manual
A Manual Meta Item must be entered by you from the keyboard during or before an Event. The template editor allows you to define different data types (numbers and strings), place limits on the range of values, or define a drop-down list of values from which the user must choose during run-time.
Numeric
The Restore Previous checkbox tells this Meta Item to use the last value recorded from the last run of the event. For instance if the last time the Event was run this Meta Item was at '15' then the next time the Event is started the Meta Item will continue and start at '15..
The Editable flag determines whether a user can manually change the value of the Meta Item.
The Auto-Increment flag tells the Meta Item to automatically add 1 to it's value for each run of the event.
An optional Internal Label can be displayed inside the input box to help the user understand what they are entering (eg 'seconds' or 'meters', etc)
The Default Value is what the Meta Item will be set to barring any other logic (see above checkboxes) override it.
The Minimum Value is the lowest number the Meta Item can be set to.
The Maximum Value is the highest number the Meta Item can be set to.
If you would prefer the user to choose from a list of numeric options rather than enter their own values you can provide those options here.
See Also: Action Sequences - Meta Item Increment
String
Options for the string variant are very similar to the numeric one, see above for details.
A Maximum Length can be set preventing the user from entering a string value with more than 'x' characters.
Global
A Global Meta Item get's it's value from a set of meta data provided to ALL events at any given moment. While these can be included in any event they can only be changed by users with appropriate rights as they will then impact all events referencing them.
The only real option for a Global Meta Item is to choose which one you want this component to point to. This dropdown is populated from the master list which is managed via the primary
Event Management page.
See Also: Global Meta Item Management
See Also: Action Sequences - Meta Item Update
Summary
A Summary Meta Item is computed automatically by the Event Logger Service at the end of an event. Using the Builder, you define the type of value to be calculated (average, minimum, time duration, etc.), and which sources form the basis of that calculation.
Summary Meta Item - Time Duration
Result is a quantity of time / duration. You can choose between using Meta Items or Outputs as your source.
Meta Item Source
Result is the difference between the LAST recorded value for the Start Meta Item and the LAST recorded value for the End Meta Item
If the same MI is selected for both start/stop then the duration will be the difference between it's first and it's last value when the event concludes.
Output Source
Result is the amount of time between the first and the last 'writes' to the selected Output.
Summary Meta Item - Average Value
Result is an average value of a numeric source. You can choose between using Meta Items , Outputs or a direct sensor feed as your source.
If you choose a direct sensor feed as your source it will average every value from the data field logged by ACQ over the course of the entire event regardless of how or even IF it is being used elsewhere in the event.
Summary Meta Item - Polar Average
Same as normal average above except using a polar coordinate system.
Use this when trying to average 'circle' type values such as COG or Heading.
Summary Meta Item - Minimum Value
Result is the minimum value of a numeric source. You can choose between using Meta Items , Outputs or a direct sensor feed as your source.
If you choose a direct sensor feed as your source it will take the minimum value from the set of every value of the data field logged by ACQ over the course of the entire event regardless of how or even IF it is being used elsewhere in the event.
Summary Meta Item - Maximum Value
Result is the maximum value of a numeric source. You can choose between using Meta Items , Outputs or a direct sensor feed as your source.
If you choose a direct sensor feed as your source it will take the maximum value from the set of every value of the data field logged by ACQ over the course of the entire event regardless of how or even IF it is being used elsewhere in the event.
Summary Meta Item - Rhumbline
Result is the distance between two points Δs, measured along a loxodrome, is simply the absolute value of the secant of the bearing (azimuth) times the north–south distance (except for circles of latitude for which the distance becomes infinite). A rhumbline appears as a straight line on a Mercator projection map.
-Wikipedia!
In other words, this summary calculation will return the distance between a starting point and an ending point as if the ship went 'straight' from one to the other. You must use a starting Lat/Lon Meta Item and an ending Lat/Lon Meta Items as your source.
Summary Meta Item - Trackline Length
Result is the distance traveled over a course of time. You can choose between using Outputs or a direct sensor feed as your source.
If you choose a direct sensor feed as your source it will take the minimum value from the set of every value of the data field logged by ACQ over the course of the entire event regardless of how or even IF it is being used elsewhere in the event.
If you choose to use an Output then the length will be over the course of the Output itself. If the Output doesn't start when the event starts, stops before the event stops, etc, then it will NOT represent the length traveled over the course of the event. If you want a trackline length for the whole event either use a sensor feed or ensure your Output starts and ends at the same time as the event (consider using the two prebuilt Auto Triggers to be safe).
The difference between a Rhumbline and a Trackline is that the trackline takes into account the curves, transects and the zip-zagging of the ship whereas the Rhumbline ignores all the meandering between the start/end coordinates and assumes a straight path.
Icons
When looking at the Meta Items you quickly determine their type by looking at the icon set on the left hand side of each component. Hover your mouse over the icon for feedback on what it represents.
