Transformation and conversion to Eng Units

Transformation and conversion to Eng Units

---

Configuring an Arithmetic Virtual Stream

An Arithmetic Virtual Stream is used when a data stream's final value requires complex calculations beyond the capabilities of a standard linear stream. It applies an arithmetic formula to the parent stream's Final Values (found in the Samples Table) to generate new Final Values for the virtual stream.

Supported Arithmetic Functions

• Operations: Addition (+), Subtraction (-), Multiplication (*), Division (/), Percentages

• Mathematical Functions:

  • Trigonometric: Sin, Cos, Tan, Asin, Acos, Atan

  • Logarithmic: Log, Log10

  • Power/Roots: Sqrt, Pow

  • Conditional: If

  • Other: Abs, Ceiling, Floor, Round, Max, Min, Trunc

• Constants: pi

Note: Arithmetic expressions are case-sensitive (e.g., abs(x) will fail, but Abs(x) works).

Steps to Configure an Arithmetic Virtual Stream

1. Access Devices:

   • In the left pane, click Devices and select Fleet Management.

2. Select Input Stream:

   • Choose the device and the stream you want to use as input.

3. Create the Virtual Stream:

   • Go to the Configuration & Threshold tab.

   • Click Create Virtual Stream and select Arithmetic Expression as the transformation type.

4. Edit the Arithmetic Expression:

   • Select the newly created virtual stream.

   • In the Convert to Engineering Units section, click the pencil icon.

   • In the Edit Arithmetic Expression window, enter the formula, including x to represent the raw value.

     • Example: 1 + Sqrt(x) * 4x

5. Submit:

   • Click Submit to apply the configuration.

Examples of Arithmetic Expressions

Name	Description	Format	Example	Result
Abs	Absolute value	Abs(x)	Abs(-1)	1
Sqrt	Square root	Sqrt(x)	Sqrt(4)	2
If	Conditional expression	If(condition, a, b)	If(x > 0, 1, 0)	1 (if x > 0)
Pow	Power	Pow(x, y)	Pow(3, 2)	9
Round	Rounds to specified digits	Round(x, decimals)	Round(1.567, 2)	1.57

For the complete list of supported functions and operators, visit NCalc Documentation.

Final Notes

• Ensure your formula uses x to represent raw values from the parent stream.

• The Final Values of the virtual stream are derived directly from the applied arithmetic formula.