Constant Value Input

Applies to: IOcan · Standalone controller. What this means

Overview

A Constant Value Input reports a single fixed number. It has no source and no sensor, but it is a real input: everything that can reference an input can reference it.

That makes it the tuning handle for the whole configuration. A threshold buried in a Compare Input has to be found and edited in place; the same threshold held in a named constant is edited once, in an obvious place, and every user of it follows.

It also does two structural jobs:

  • Filling a Mux Input's unused slots, which is not optional — all eight must be assigned or the configuration faults.
  • Supplying a fixed operand to a Math Input, where one side of the operation is a number rather than a channel.

A constant is often the limit a Compare Input tests an ECU-provided signal against. The ECU integrations say which signals your ECU actually sends, and which it does not.

Prerequisites

None.

Add it in the app

  1. Add a new input and choose Constant Value Input as the type.
  2. Give it a clear name — name it for what it means, not what it equals. Shift Pressure Limit survives being retuned; Pressure 850 does not.
  3. Enter the value.

Settings reference

Setting Meaning Unit Range / values Notes
Value The number this input reports whatever the consumer expects sint32 May be negative. Integer only — work in tenths or hundredths where you need a fraction.

There is no scaling here. The value is delivered exactly as entered, so it must already be in the units and scale the consumer works in — a percentage read against the 1024 convention needs 512 for 50 %, not 50.

Common settings

Constant Value Input also uses the shared Name setting. See Common IO settings.

Example — a threshold you can retune

  1. Type Constant Value Input, name Low Pressure Limit, value 850.
  2. In a Compare Input, set the source to your measured pressure and the value to 850.

Keep both in step, or better, point everything that cares at the constant so there is a single place to change.

Example — filling a mux

A Mux Input needs all eight data slots assigned even when you use two. One constant named Mux Unused covers the remaining six, and gives an out-of-range mode a defined value instead of a frozen one.

Troubleshooting

  • The value looks wrong at the consumer: it is delivered unscaled. Check which convention the consumer works in — 1024 full scale, volts, tenths.
  • Retuning it changes nothing: the consumer has the number typed in directly rather than referencing this input.
  • A fraction gets lost: everything is integer. Work in tenths and account for it downstream.