Prerequisite : This feature is available for users with a functional administrator role.
Consider the following example :
Imagine we have an operation spread across 2 different regions, with 2 sites per region and 1 compressor per site.
Each compressor sends two different metrics: hydrogen flow rate and pressure. These two metrics are associated with a metric template.
For each compressor, we want to know the volume of hydrogen compressed.
To do so, we need to create a formula where we multiply our two metrics:
Volume (calculated metric) = flow (metric 1) * pressure (metric 2) * compression coefficient.
To avoid creating a formula for each compressor, you can create a formula template that will automatically generate a formula for each compressor.
To create a formulas model, connect to Io-base, then go to the Functional Tree menu.
Then, select the desired tree structure.
Go to the Types tab, and select the type of element for which you want to create a generic formula.
At the bottom right of the screen, the section "Associated formulas" is available.
Click on "Add a formula template".
A pop-up window opens to allow you to configure your formula model.
Configuration of the Model
A first section allows you to specify the naming parameters of your formula model :
Generic Name : This is the name of the metric model; in our case, we choose to name it "Volume"
Metadata type : Select a "Metric" type
Display options : This parameter controls how generic metrics are displayed in the tree structure. You can choose to display the metrics using their name, their description, or the generic name of the model.
Metric template
In this section, you need to specify :
the database where you want to store the formulas generated by your model :
the naming of Indaba metrics related to the formula model :
For example :
Note : You have an input assistant available where you can retrieve various properties from your tree structure. To open it, click on the enclosed button below :
In our example, we used the property {CodeCip}, which returns the compressor code, to name our metric.
Formula template
The "Formula Model" section allows you to enter the expression of your model :
To enter the expression of the model, you again have an input assistant available.
Click on the button
.
On the right side of your screen, the input wizard opens :
It allows you to add to your expression:
the properties of the functional tree :
the generic metrics present in the functional tree, represented by the symbol
All the operators from the Formulas menu :
In our example, we will have :
Note : The generic metrics used in the formula expression are enclosed in brackets '[ ]' and the properties of the tree structure in curly braces "{ }".
Formula Configuration
As with the creation of a standard formula, you need to specify parameters for the formulas generated by your model :
the calculation periodicity: the frequency at which the metric values will be calculated
a description (optional), where you can add parameters using the input wizard :
an unit (optional)
data validity in seconds (optional) : this value ensures that calculated values are based on valid data.
For example, if the expression is main@tag>5, and the validity duration is set to 60 seconds. At the time the formula needs to recalculate, it will check the timestamp of the last value in the database for main@tag. If this timestamp is older than 60 seconds, the value is considered unreliable. Therefore, the formula will not recalculate, and no new value will be inserted at that time.
If you want to recalculate a value regardless of this validity check, simply enter 0 in this field.
result type (mandatory) : indicates in which format the calculated values will be stored in the database :
BOOL: boolean
INT: integer
REAL: decimal
timezone (mandatory): specifies the time zone you want to set for your formula.
Note : An input assistance is provided; simply type the beginning of your input, and the available time zones will be displayed.
Once all the parameters are entered, you can save your formula model.
Your model appears correctly in the "Associated Formulas" section.
