ITPEC IP October 2023 Question 13
There is an IoT system that automatically opens and closes the sluice gate for a rice field by measuring the water level in the rice field. Which of the following is the appropriate combination of terms to be inserted into blanks A and B in the figure?
Explanation
A: Sensor, B: Actuator — A turns the water level into data, B turns the server's instruction into movement of the gate.
Follow the arrows through the IoT device:
- •Water level → A → communications module → server: A measures a physical quantity and turns it into an electrical signal, which is a sensor
- •Server → communications module → B → sluice gate: B receives the instruction and physically opens or closes the gate, which is an actuator (a motor, for example)
Answer (d)
Why not others:
- •(a) — an actuator does not measure anything, and B drives the gate rather than relaying data
- •(b) — swaps the two: an actuator cannot read the water level, and a sensor cannot move the gate
- •(c) — A is right, but an IoT gateway relays data between devices and a network or server; that job is already done by the communications function module, and a gateway moves no gate
Key rule: In a control loop a sensor converts the physical world into data (input), and an actuator converts a control signal into physical action (output).
Hardware · AI-written, may contain errors
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