ST-700 Inline pH / ORP / Conductivity Sensor With Embedded Transducers

The Pyxis ST-700 series of pH, ORP, and conductivity probes are designed to simplify installation, calibration, and in-use operation in industrial wastewater and cooling water applications. These probes have an embedded 4~20mA transmitter.

The oversized platinum disk ORP and the flat pH bubble sensing elements increase resistance to contamination. The double salt bridge design with large junction capacity ensures a long sensor life with minimum maintenance.

Typical Applications

Industrial wastewater treatment, cooling water treatment


  • Dual embedded transmitters in sensor housing: 4-20mA and RS-485 supporting MODBUS.
  • Large conjunction capacity (compared to replaceable electrode design) leading to longer service life.
  • Longer maintenance cycles with high contamination resistance. Eliminates the need of pre-amplifier and transfer signal directly in 4~20mA or digital protocol.
  • Enhanced robustness when controller is away from sample point.
  • Specially designed pH/ORP electrodes tolerant to short time frozen during shipment or storage.
  • Stainless steel solution grounding point on sensor to stay away from ground loop problems.


Items Specification
pH 0~14 range with ATC,±0.01 pH unit precision
ORP ±1500mV range,±1mV precision
Conductivity 1~15,000 uS/cm
Temperature 0~65℃(32~149℉)
Response Time 95% within 5 sec
Power Supply 12-36V DC,~1W
Output 4~20mA isolated,RS-485 isolated
Connector Custom IP67 waterproof connector,1.5m(4.5ft)
Operation Pressure Up to 0.7 MPa(100 PSI)at 65℃(149℉)
Installation Custom 3/4inch tee with NPT thread
Storage temperature -20℃~60℃(-4~140℉)
Operational temperature 0℃~40℃(32~104℉)
Typical service life pH/ORP 2 years,Conductivity 5 years
Housing material CPVC
Dimension 172mm long,36.6mm diameter(6.8inch long 1.44inch diameter)
Weight 170g (0.37lbs)
Regulation CE