IA Irrigation Controllers & Automation 1 — Questions and Answers
Question 1: What is the primary function of an irrigation controller?
- To filter sediment from irrigation water
- To automatically open and close valves according to a programmed schedule (Correct answer)
- To regulate mainline water pressure
- To measure soil nutrient levels
Correct answer: To automatically open and close valves according to a programmed schedule
An irrigation controller (timer) operates solenoid valves on a preset schedule, automating the opening and closing of irrigation zones without manual intervention.
Question 2: A rain sensor on an irrigation controller is designed to:
- Measure soil moisture levels
- Interrupt or delay scheduled irrigation when sufficient rainfall occurs (Correct answer)
- Increase run times during dry weather
- Alert the controller to low-pressure conditions
Correct answer: Interrupt or delay scheduled irrigation when sufficient rainfall occurs
Rain sensors interrupt or postpone irrigation when rainfall exceeds a set threshold, preventing unnecessary watering and saving water.
Question 3: A two-wire decoder irrigation system differs from a conventional controller system because:
- It uses wireless radio signals only
- It runs all field wiring from the controller through a single pair of wires to decoder modules at each valve (Correct answer)
- It requires no controller at all
- It uses higher voltage to power the solenoid valves
Correct answer: It runs all field wiring from the controller through a single pair of wires to decoder modules at each valve
Two-wire decoder systems replace multi-conductor cables with a single two-wire path carrying both power and communication signals to individual decoder modules at each valve.
Question 4: Which controller feature allows a user to temporarily increase or decrease all run times by a percentage without reprogramming each zone?
- Station delay feature
- Seasonal adjust (water budget) percentage (Correct answer)
- Master valve override
- Rain delay setting
Correct answer: Seasonal adjust (water budget) percentage
The seasonal adjust or water budget feature multiplies all station run times by a set percentage, allowing quick seasonal changes without editing each station individually.
Question 5: A master valve (MV) in an irrigation system is installed:
- At each sprinkler head
- On the mainline upstream of all zone valves, and opens only when a station is active (Correct answer)
- Inside the controller cabinet
- At the well pump discharge
Correct answer: On the mainline upstream of all zone valves, and opens only when a station is active
The master valve is a normally-closed valve on the mainline that the controller opens whenever a station runs; it prevents water waste from valve leaks when the system is off.
Question 6: What type of sensor can be wired to a controller's sensor input to automatically suspend irrigation when the soil has sufficient moisture?
- Anemometer
- Soil moisture sensor (tensiometer or capacitance probe) (Correct answer)
- Flow meter
- UV sensor
Correct answer: Soil moisture sensor (tensiometer or capacitance probe)
Soil moisture sensors measure water content or soil water tension and can interrupt scheduled irrigation when the soil is already adequately moist.
IA Irrigation Controllers & Automation 1
What is the primary function of an irrigation controller?