System Input¶

Overview¶

A System Input exposes an internal system value — a quantity produced by the
controller itself rather than measured on a wire. Which value it reads is chosen
by the pin, which acts as a selector. Available values are:

• Battery voltage — the supply/battery voltage at the controller.
• Ignition status — whether ignition is on.
• 5 V measurement — the controller's internal 5 V rail reading.

Use it to bring one of these into your configuration so other IO can reference it
by alias.

Prerequisites & hardware¶

• None to wire. A System Input reads an internal value, so there is no sensor
  and no source input.
• You only need to choose which system value to read — done by the pin/selector
  (see below).

Add it in the app¶

1. Add a new input and choose System Input as the type.
2. Choose the pin / selector — this picks which system value the input reports
   (Battery voltage, Ignition status, or 5 V measurement).
3. Give it a clear alias (e.g. the name of the value you selected).

Settings reference¶

This input has no type-specific settings. Which system value is read is chosen
by the pin / selector, not by any field on the input.

Common settings¶

System Input also uses the shared settings — alias and pin. Here the
pin is the selector that picks the system value. See
Common IO Settings.

Example — low-battery warning¶

1. Type System Input, selector Battery voltage, alias Battery V.
2. Feed Battery V into a Compare Input set to
   LessThan 11500 (mV) to flag a low battery.

Troubleshooting¶

• Reads an unexpected quantity: the selector is set to a different system
  value — reselect Battery voltage / Ignition status / 5 V measurement.
• Other IO don't see it: check they reference the correct alias.

Related¶

• Virtual Input — an externally-written value with no hardware.
• Constant Value Input — a fixed configured value.