HI 9914 is a wall mounted fertigation controller, designed to meet specific process control requirements in agricultural, horticultural and hydroponics applications. The controller is provided with two measuring channels, one for pH and one for conductivity. The readings are displayed simultaneously on two independent LCDs with backlight.

The conductivity probe is designed with a built-in temperature sensor which allows the controller to automatically compensate for the temperature effect. The differential input and the use of a Matching Pin prevent grounding problems and thus ensure longer life to the pH electrode.

The controller includes two regulators for pH and conductivity, that can be adjusted from the front panel by setting two independent thresholds. The conductivity and pH controls are time separated and a timed operation mode to avoid overdosing of fertilizer or acid. The controller status is indicated by LEDs on the front panel. Moreover, the equipment is provided with a three-level sensor, to control the water level, the alarm condition and irrigation sequences.

The instrument also features an alarm system, which is activated when an unusual working condition occurs. A humidity detector can be used to stop the controller if any leakage is detected. Water nozzle, circulation pump, feeding pump and alarm are equipped with relays.