What Is the Difference Between an AI Module and an AO Module?

The Founder's Explanation (Teach Exactly This Way)

"Ear and mouth. Ear only listens — it takes in. Mouth only speaks — it gives out. Same face, two opposite jobs. AI module is the ear — it listens to the sensor. AO module is the mouth — it speaks to the valve. If you talk into your ear, nothing happens. That is why a swapped board never works."

Teaching the Concept

The Ear and the Mouth Your ear only listens; your mouth only speaks. Same face, opposite directions. Talk into your ear and nothing happens. An AI board listens to sensors; an AO board speaks to actuators. Swap them, and the plant goes deaf or mute. The whole difference is direction — in or out. Input Listens, Output Acts ``` AI MODULE (Analog INPUT) signal flows IN from: 4-20mA / 0-10V sensor reads: temperature, %RH, pressure, feedback AO MODULE (Analog OUTPUT) signal flows OUT to: 0-10V actuator / positioner drives: valve, damper, VFD speed reference ``` Never Confuse Them Again ``` Ask: is the device SENSING or MOVING? Sensing -> AI Moving -> AO ``` Input listens, output acts — keep the direction straight and the plant does exactly what the program intends.

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Related Topics

• What are analog and digital signals in BMS? — a range versus an on/off state
• What are 4-20mA and 0-10V signals? — the common analog signal standards
• Browse all IO List & Wiring topics — more from this section of the EnSmart BMS Library