This is the first of three short tutorials. You build a model with three blocks, a Sine source, a Gain, and a Scope, then run it and read the result. The model has no feedback and no dynamics, so it is a good way to learn the editor itself: placing blocks, drawing wires, editing parameters, and running a simulation.

Open the editor

Call nflow() from the Nelson command line to open an empty model. The block library is on the left, the diagram canvas is in the center, and the inspector is on the right. Select a block to see its parameters in the inspector, or select nothing to see the Model tab with the simulation settings.

Place the blocks

In the library, open the Source group and drag a Sine block onto the canvas.

Open the Math group and drag a Gain block to the right of the Sine block.

Open the Sinks group and drag a Scope block to the right of the Gain block.

Leave room between the blocks so the wires have space to route.

Connect the blocks

Move the pointer over the output port on the right of the Sine block, then drag to the input port on the left of the Gain block. Release to create the wire.

Draw a second wire the same way, from the Gain output to the Scope input.

When autoRoute is on, the editor keeps the wires orthogonal and clear as you move blocks. See nflow_wire_editing for manual routing, corners, and junctions.

Set the block parameters

Select the Gain block and set Gain to 2 in the inspector. Select the Sine block to set its amplitude and frequency, or keep the defaults. Each change is applied to the block as you type.

Set the run duration

Select nothing to show the Model tab, then open Simulation. Set Runtime (s) to the length of the run, for example 10. Leave Sample Time (s) at its default for this model.

Run the model

Press Run in the toolbar above the diagram, or use the Simulation menu. The Scope fills while the model runs. Stop ends the run and keeps the results already computed. Reset returns time to zero and clears the displayed results.

Read the scope

The Scope shows the amplified sine wave. Select the Scope and use the inspector to set the time and value ranges (t min, t max, y min, y max), to show tick labels, and to set the trace color and axis labels. Leave a range field empty to let the Scope fit the data.

What to try next

Replace the Sine with a Step or a Pulse from the Source group to see how the output follows a different input. Then continue with nflow_tutorial_continuous to add an integrator and choose a solver.

nflownflow_workspacenflow_wire_editingnflow_tutorial_continuousnflow_tutorial_dashboard