Industrial Engineer · phase 2 of 16
AO / Analog Output
Output that sends a continuous command signal such as 4-20 mA or 0-10 V to another device.
The Explain card
- Plain English
- An analog output sends a continuously variable command out of the controller. Instead of on or off it says forty percent, or twelve milliamps, or seven volts.
- Example
- The PID loop for a tank level writes its result to an analog output. That output drives a control valve to whatever opening the loop asks for.
- Why it matters
- Drives, valves and dampers all take their setpoint this way, so a loose analog wire makes a valve drift without any fault appearing. Set the channel's fault state so a lost controller cannot leave the valve at its last command.
- Hook
- The controller's dimmer switch.
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.
