Industrial Engineer · phase 2 of 16
AI / Analog Input
Input that measures a continuous electrical signal such as 4-20 mA, 0-10 V, resistance, or thermocouple voltage.
The Explain card
- Plain English
- An analog input measures a signal that varies smoothly rather than switching on and off. Temperature, pressure, level and speed usually arrive this way.
- Example
- A pressure transmitter sends 4 to 20 mA into an analog channel. The card converts it to a number, and the program scales that number to pounds per square inch.
- Why it matters
- Every analog point needs a range, a wiring type and a scaling before it means anything. A channel configured for voltage while the transmitter sends current reads garbage that looks like a valid value.
- Hook
- Discrete says whether, analog says how much.
Where it sits in the deck
Phase 2: PLC I/O and Field Signals
Where the controller meets the machine: discrete and analog signals, the wiring conventions behind them, and the field devices that send them.
