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Hanna Instruments Canada
Customer Support: (800) 842-6629

Conductivity Process Digital Controller – HI720


In stock

Hanna’s innovative, high-specification 720 series conductivity controllers offer economical, constant monitoring of Electrical Conductivity (EC). HI720 is a PID, PI, proportional or on/off EC/TDS controller with one or two set points.

  • RS485 communication with additional capabilities, such as error log file downloading and cleaning commands.
  • Alarm configuration can be customized: different errors can lead different actions.
  • Mount probes directly or use a digital transmitter for large distances.


Short Messaging Service (SMS)

It is possible to connect the controller to a GSM cellular engine (HI 504900 or HI 504901). This connection enables the instrument to send SMS to one (or two) cellular phone(s) and through this feature the device can be monitored at any moment. Moreover, if an error occurs on the HI 720, it is possible to receive an alarm SMS which immediately advises about the problem.

In-Line Cleaning

The cleaning feature allows an automatic cleaning action of the probe. Simple cleaning, with water only, can be triggered only by a timer (periodical cleaning) or by an error for which a cleaning action can be configured. Advanced cleaning, with water and detergent, it can be triggered by a variety of events.

Continuous Temperature Monitoring

Temperrature is continuously monitored using a temperature sensor (Pt100 or Pt1000 type) with ATC of conductivity. Conductivity temperature compensation parameters are fully customizable: linear or non-linear temperature compensation, reference temperature and temperature coefficient. Users can define the specific curve of temperature compensation.

Programmable Hold System

The hold function allows the user to stop the regulating action of the controller for programmable time periods. It is possible to activate the hold periods in correspondence to programmed operations, such as plant maintenance and cleaning procedures.

Logging Capabilities

The controller logging feature can save the last 100 error, configuration, calibration and cleaning events. This information can be accessed from a PC through RS485 and HI92500 software.

Fail-Safe Alarm System

Hanna’s exclusive Fail Safe Alarm System protects against problems caused by power supply failure or signal interruption, which are typical risks in industrial environments. An alarm condition is indicated by a red LED, located directly on the front panel.

Additional information



EC Accuracy

±2% f.s.

EC Resolution

1 µS/cm (0 to 1999 µS/cm) 0.01 mS/cm (2.00 to 19.99 mS/cm) 0.1 mS/cm (20.0 to 199.9 mS/cm) 1 mS/cm (200 to 2000 mS/cm)

Temperature Accuracy

±0.5°C / ±1°F

Temperature Range

-30 to 130°C / -22 to 266°F


SKU HI720-web
Name Conductivity Process Digital Controller – HI720
EC Range 0 to 2000 mS/cm (auto-ranging)
EC Resolution 1 µS/cm (0 to 1999 µS/cm)
0.01 mS/cm (2.00 to 19.99 mS/cm)
0.1 mS/cm (20.0 to 199.9 mS/cm)
1 mS/cm (200 to 2000 mS/cm)
EC Accuracy ±2% f.s.
EC/TDS Temperature Compensation Automatic or manual, -30 to 130°C
Temperature Range -30 to 130°C / -22 to 266°F
Temperature Resolution 0.1°C / 0.2°F
Temperature Accuracy ±0.5°C / ±1°F
Dosing Terminals 1, 2, 3 or 4 electromechanical relays SPDT; 5A-250 Vac, 5A-30 Vdc (resistive load); fuse protected: 5A, 250 V fuse
Alarm Relay Set Point 1 electromechanical relay SPDT; 5A-250 Vac, 5A-30 Vdc (resistive load); fuse protected: 5A, 250 V fuse
Analog Input Signal 1 or 2 independent outputs; 0-22 mA (configuring as 0-20 mA or 4-20 mA)
Digital Input Signal Digital Transmitter, Hold & Advanced Cleaning inputs
Digital Output Signal 1 digital insulated contact closed upon Hold mode
Power Consumption 10 VA
Max. Oscillation Frequency 8 MHz
Enclosure Single case 1/2 DIN
Power Supply 24 Vdc/ac, or 115 Vac or 230 Vac or 100 Vac ±10%, 50/60 Hz; fuse protected: 400 mA, 250 V fast fuse
Weight Approx. 1.6 kg (3.5 lb.)


Conductivity Process Digital Controller – HI720