In case electric power (220 V AC) on site is available (i.e. Greenhouse, many lawn & garden applications) an alternative to the use of an irrigation controller does exist, the direct control, because standard electro valves with solenoid can be directly controlled by switch Tensiometers and Now_SMS units.
In any case the electric voltage is reduced by a transformer to safe 12 or 24 VAC.

Switch units for Mode of Operatiion A with grid power:

MMM switch Tensiometer, Irrometer switch Tensiometer, WS Water Switch 24V AC, WEM Watermark Electronic Module 24V AC, WEM-DC-T with Timer 24V AC, Now_SMS (all models with sensors for soil moisture (e.g. NOS-H2O)

Switch units for Mode of Operatiion B with grid power:

MMM switch Tensiometer, Irrometer switch Tensiometer, Now_SMS (all models with sensors for soil moisture (e.g. NOS-H2O)

Irrigation Controller

X-Core by Hunter

Up to 4 start times per day, with sensor port, pump start relais, integrated transformer, weather proof housing.

I-Core by Hunter

Up to 8 start times per day, with sensor port, pump start relais, integrated transformer, lockable weather proof housing. Can be extended to up to 30 stations.

Electro Valves 24V AC

by Hunter

Plastic, with 24V AC solenoid and flow regulation.

Illustrations on this page by courtesy of

• Automation WITHOUT electric power on site