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Your first signal - an internal signal

In this tutorial you create your first signal. It is an internal signal: YTCC keeps its value itself, so you need no device or driver. Later tutorials draw it on a screen and change its value.

Before you begin​

  • You have a project, for example Pump Station. See Create your first project.
  • Your user may edit the configuration. With user login off, everybody may.

Steps​

1. Open the configuration editor​

On the home page, right-click the project and choose Configuration editor. The configuration editor opens in a new browser tab, on the Signals list. A new project has no signals yet.

Configuration editor of Pump Station with the empty Signals list.

2. Add a numeric signal​

Click Numeric in the toolbar of the Signals list. A new row appears at the top under New — not applied, with its name selected. Type Level_Setpoint and press Enter.

New Level_Setpoint row of type Float64, role Measurement and source Internal (memory), marked as not applied.

The row shows the type Float64, the role Measurement and the source Internal (memory). The status bar at the bottom says 1 unapplied changes: the signal exists only in the editor so far. A name starts with a letter or _ and contains only letters, digits and _.

3. Apply the change​

Click Apply (1) in the toolbar, or press Ctrl+S. The Validate changes window checks the change on the server and lists it. It says No errors, and under Affected drivers it shows that int, the driver of internal signals, will be reloaded without a restart. Click Apply.

Apply result window with Insert 1, Update 1 and Errors 0, and int — will hot-reload under Affected drivers.

The Apply result window confirms the change. Click OK. The status bar now says Ready and shows the time of the last apply.

4. Check where the value comes from​

Click the signal's row and press Enter to open its Signal properties window. Open the Value source tab:

  • Value source (kind) is Memory — holds a value (operator/script writes): the value is kept by YTCC and changed by an operator, a screen or a script.
  • On startup is Keep last value: after a restart the signal has its last value again. Initial value (0.0) is used when there is no last value yet.
Value source tab with Memory as the value source, Keep last value on startup and initial value 0.0.

Click Cancel to close the window without changes.

Result​

The project has the signal Level_Setpoint, an internal numeric signal with the value 0.0. Its value is visible in the Value column of the Signals list while the project is running.

Next steps​

  • Create signals describes every way to add a signal and every field of the Signal properties window.