# Constant/Simulated Variables¶

When Digital Twin is created from an hybrid model, the digital twin automatically recognizes the hybrid model dependent variables and creates them for you. Those are the minimum required Constant/Simulated variables needed to be able to run the Hybrid model.

Additionally, user can add as many additional Constant/Simulated variables as needed to implement a desired digital twin.

Important

When adding a new Constant or Simulated variable, name can only be set during creation. If provided name contains spaces or invalid C# variables name characters, those will be automatically filtered. This restriction, only applies for the Variables Name; a friendly Display Name for reports can be set independently (when needed) for all variables.

## Constant Variables¶

Important

Be careful with the amount of Constant variables added and specially its resolution (small resolution steps), as resulting total combinations number can become extremely big quite fast. On one hand this will impact your simulation time, as more simulations need to be performed, but on the other hand, you might run out of RAM memory and Windows might terminate Toolbox application without any notice; losing all unsaved work.

Constant variables, are used to indicate the digital twin that variable will be constant for the whole duration (X-Axis) of each combination simulation.

This type of variables allow user to set different conditions (combinations) where variable should be evaluated (see example).

### Parameters¶

#### Sim. (Min.) [u]¶

Range numeric start value (included).

#### Sim. (Resol.) [u]¶

Range numeric step value.

#### Sim. (Max.) [u]¶

Range numeric stop value (included).

### Example¶

Assume we have 2 constant variables, Temperature and RPM,

Var. Name

Sim. (Min.) [u]

Sim. (Max.) [u]

Sim. (Resol.) [u]

Temperature [C]

30

37

5

RPM

300

500

100

In this case, digital twin is told that should perform simulation for,

• Temperature: 30, 35, 37

• R.P.M: 300, 400, 500, 600

Because of that, 9 total simulations (as many as possible combinations) will be carrier out.

Sim No.

Temperature [C]

R.P.M

1

30

300

2

30

400

3

30

500

4

35

300

5

35

400

6

35

500

7

37

300

8

37

400

9

37

500

## Simulated variables¶

Simulated variables are used as Extended Variables along the custom code and are included in the digital twin report. Therfore, they can be plotted along Constant and Output variables within the report section.

Some/All simulated variables can be considered as outputs depending of each specific use case.