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The D-pHi Series™

4-20 mA Differential ORP Sensor

If you want a user-friendly, low-maintenance ORP monitoring system, then this 4-20 mA ORP (redox) sensor is your answer.

Enjoy hassle-free installation, calibration, and cleaning.  Avoid headaches like ground loops, electrode poisoning, and electrode replacement thanks to the differential electrode.  With all these benefits, a 2-year warranty, and exceptional product support*, this ORP sensor serves up incredible value for your business.

Oh, and it is designed to last 10+ years.

Order now to experience the D-phi difference.

*Support includes comprehensive troubleshooting resources, responsive customer service, and discounted rebuilding or replacement services in the event of damage.


Recommended for process control, wastewater, aquaculture, hydroponics, environmental remediation, and other applications requiring user-friendly and low-maintenance ORP sensors.

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D-phi Series ORP Sensor Features

  • Refillable electrode that never needs replacement
  • Chemical-resistant titanium and Delrin® housing (PVDF available)
  • Built-in 0-50°C temperature sensor (secondary 4-20 mA output)
  • 3/4 or 1 NPT backend (depending on model)
  • Fully submersible to 100 psi and 150°F
  • Dry storage
  • Automatic Temperature Compensation (ATC)
  • 600 VDC electrical isolation
  • 2-wire connection with Reversible Input Protection


The d-phi Series is fully submersible up to 100 psi

Model D-phi-s


Model D-phi-s has a 3/4″ NPT thread for standpipe mounting.

Model D-phi-s


Mount model D-phi-i inline up to 100psi with the built-in 1″ NPT thread.

Model D-phi-i

Additional Resources

pH Sensor Mounting Options

pH Sensor Inline and Standpipe Mounting Guide

ORP Sensor

ORP Range -1000 to +1000 mV
Output 4-20 mA | 2-wire
Electrode Type Differential
Wetted Materials Delrin®, titanium, glass, platinum, Viton™
Operational Temperature Range 32-155°F (0-70°C)
Thread Type 3/4 inch MNPT or 1 inch MNPT
Max Flow Rate 10 ft per second
Pressure Range 0-100 psi
Automatic Temperature Compensation 32-155°F (0-70°C)
Power Supply Voltage 8-40 VDC
Warm-up Time 2 seconds
Response time 95% < 5 seconds
Length 9.25 in (23.5 cm)
Width 1.00 in (2.54 cm) max.
Weight (No cable) 0.50 lbs (0.227 kg)
Linearity ±4 mV*
Accuracy ±4 mV*
Sensitivity 1 mV

*After proper calibration


Cable Material Polyurethane
Type Kevlar® reinforced, water blocked, shielded, twisted-pair wiring
Maximum Distance 3 miles
Resistance per 1000 ft (304.8 m) 26 Ohms

pHionics products comply fully with all applicable EU Directives to bear the CE Mark.

Delrin® and Kevlar® are registered trademarks of DuPont™.

Viton™ is a trademark of Chemours.

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