Sensors

Behavior of tables

The column header is like a search bar, with ...

• Dynamic search on text fields.

• Filtering on selected items.

• Sorting on all columns.

Some more features:

• It has input functionality, depending on given rights.

• You can delete entries, again depending on given rights.

• It’s smart if you want to see more lines, but fast because it does not show all data. It doubles the number of extra entries shown each time the icon in the caption area is clicked.

Virtual and manual sensors

Instruments and sensors will be automatically created on import. In case of virtual or manual sensors, you will want to create these yourself, since there is no data available to import.

New sensors can be created under the SENSORS tab. Make use of the plus sign + at the bottom of the sensor table. An instrument (whether virtual or not) must be entered. Next, fill in the formula of the virtual sensor or set the manual flag to mark the sensor as such.

Transferring sensors

You can easily transfer a sensor to another instrument, using the drop-down list in the first column of the sensors table. This will not be a problem for new sensor data. Vision 42 will remember where the data was coming from. This is visible in the origin column.

Time lag

Per sensor, the average time lag is displayed in the sensors table. Its unit denotes either milliseconds (ms), seconds (s), minutes (min), hours (h), days (D), weeks (W), months (M), or years (Y).

Do-it-yourself profile plot

In case you need a profile plot, but your data does not contain vertex positions, do the following:

• Enter the vertex positions in the sensors table.

• Enter a name for the axis in the instruments and data loggers table.

• (Re)import your data.

Formulas

Introduction

Let's start off with a simple example. Given are two instrument sensors, BH1-level and BH2-level. Create a new sensor difference at the bottom of the sensor table, for example under instrument BH1. For the sensor difference, enter the formula [123]-[345], using the corresponding keys to the right of the sensor table.

In the tooltip of the formula you will find a summary example in terms of syntax:

[key1]>1,2 ? 3.4E-5**6 : log([key2];10)+elevation²-position³

Note that:

• A formula may be split over multiple lines and white space can be added, for readability.

• A leading hash sign ( # ) will disable a formula.

• There is no leading equal sign ( = ), like Microsoft Excel requires.

Numbers

• Both point ( . ) and comma ( , ) may be used as the decimal separator.

• Numbers can be written in exponential notation.

Identifiers

• The lowercase letter x is shorthand for the own sensor [key].

• The words elevation, surface, and position will be replaced by their corresponding values.

• The word null may be used to omit a value.

• These predefined constants can be used.

Operators

• The power operators are **, ^, ², and ³.

• The ternary operator ( ? : ) is allowed and provides if-then-else functionality.

• More operators and their precedence can be found here.

Out-of-band filter example:

-42<x && x<42

? x

: null

Functions

• Function parameters must be separated by a semicolon ( ; ).

• These math functions can be used.

Error handling

Broken formulas will automatically be disabled on calculation, accompanied by a helpful error message. Example:

# Call to undefined function ln()

ln(x)

Additionally, both upload and continuous input will show the error.

Cyclic references will also be detected and disabled.

Calculation

Whenever a source sensor changes, the formula will be calculated. Notable exceptions:

• A (calibration) formula which depends on its own sensor, will only be calculated when itself changes.

• A formula of a manual sensor will only be calculated when a manual source changes.

The calculations can also be done for the past. Re-importing is the trigger for this. Additionally, virtual sensors can be (re)calculated by the press of a button.

You can clone a single sensor using the simple formula [123].

The measurement freshness in formula calculations is asymmetrical:

• 210% of the interval for earlier values, keeping late arrivals in mind.

• 110% of the interval for later values, to allow for small interval variations.

Calibration

Calibrated sensor data can be achieved by adding a calibration formula to a sensor.

In case this formula depends on the own sensor, the original value will be replaced by the calibrated value. Such a formula will only be calculated for the points in time of the original sensor.

Alternatively, a virtual sensor can be used to store the calibrated data alongside the original data.

Air pressure compensation

The automatic air pressure compensation only uses linear interpolation.

Repurpose instruments or data loggers

Administrators can clear an instrument id. On arrival of new data, a new instrument will be created automatically.

Override outages

The automatic detection of outages can be overridden. To do so, fill in the outage field in the instruments and data loggers table, by specifying the desired time lapse in minutes.

Confirm alerts and outages

Vision 42 can repeat alerts and outages every 15 minutes until they have been confirmed. To do so, make use of the confirm flag in the instruments and dataloggers table. The messages will indicate which instruments have to be confirmed:

Subject: [alert] Example project

BH-11: yellow -> green

BH-42: green -> red (level = -1.96 > -2 m & confirm)

https://vision42.net/your-organization/#section=confirmed

https://vision42.net/your-organization/#section=plot&instruments=42

Click or tap that first link to confirm the alert or the outage. A confirmation message will automatically be sent:

Subject: [confirmed] Example project

To: you and relevant colleges

Reply-To: your@address

BH-42 -> Your Name

https://vision42.net/your-organization/

Without project

This table lets you easily manage instruments which are not linked to a project:

• Change their names.

• Set or change their instrument types.

• Link them to a project.

• Completely delete an instrument, its values regardless of validity, its sensors, and its files.