Glossary · Electrical engineering and control panels
Input signal
Also known as: Input
German: Eingangssignal
In control engineering, an input signal is a physical signal fed into a controller, device or system, such as a voltage, current, pulse train or bus telegram, that carries information about a state or value.
- Control panels
In one sentence
An input signal is a physical signal fed into a controller or device that carries information about a state or value.
Example
The encoder's pulse trains are the input signal from which the counter module calculates the conveyor position.
How it applies
- Engineering: Specify each input signal by type, range, timing and fault conditions, so the receiving device can be selected and configured correctly. Interface specifications should describe signals at the same level of detail on both sides.
- Commissioning: Verify signals with a meter or test device at the terminal before blaming the program; this separates wiring faults from logic faults.
- Documentation: In interface descriptions, distinguish the physical signal (for example 4–20 mA) from the Input value the program uses (for example 0–10 bar). Mixing the two causes scaling errors.
Input signal vs. input value
The input signal is physical, at the terminal. The Input value is its digital representation in the controller after conversion and scaling.