ORP485 - redox probes with RS485 output

sondy pro měření redox potenciálu s RS485 výstupem

  • Basic element for creating RS485 sensor network for dataloggers and on-line IoT systems (Lora, Sigfox, NB, GPRS)
  • Accurate REDOX potential measurement without additional transducers and other electronics
  • Platinum measuring electrode with a diameter of 4 mm and a gel electrolyte with a diaphragm
  • Calibration coefficients stored in the probe
  • Measuring ranges -2000 mV to +2000 mV, -5 to +60° C
  • Lifespan 3 to 5 years with extended recalibration interval
  • Galvanically separated communication and power supply circuits from the measuring electrode
  • Wide supply voltage range from 5 to 24 V DC, low current consumption
  • Low cost
  • Variant design of probes for measuring pH (PH485) and voltage of ion-selective electrodes (ISE485)

Basic description

The ORP485 probe is intended for measuring the redox potential. The mechanical design of the probe combines into one compact unit a platinum measuring electrode, a reference argent chloride electrode separated from the measured solution by a diaphragm and a measuring electronics controlled by a microprocessor.

In order not to influence the measured quantity by the action of earth currents and induced interfering potentials, the measuring circuits, including the electrode itself, are galvanically separated from the communication and power supply cable of the probe.

The self-cleaning design of the used reference electrode ensures a stable and reproducible signal even in the environment of emulsions, suspensions and other adhering impurities of various origins as well as impurities caused by a chemical reaction. The electrode thus largely eliminates, for example, the negative effect of rust, hard water (Ca, Mg compounds in both carbonate and sulfate forms), oil emulsions, adhering organic and inorganic impurities.


The compact ORP485 probe with digital data output represents a modern solution for accurate measurement of the oxidation-reduction potential in many water supply industries and industries:

  • Wastewater treatment plants
  • Chemical and food industry
  • Swimming pools
  • Research and development projects
  • Environmental monitoring, soil measurement

Mechanical design of probes

The ORP485 probe body contains a G 3/4" mounting thread on the electrode side (for mounting the probe in the piping system) and on the cable outlet side (mounting the probe in a holder or sensor).


sondy pro měření redox potenciálu s RS485 výstupem

The cable terminated with an M12 connector on the ORP485-KxM12 probe facilitates the installation of the probe in the TS500 rod sensor (TS1700) and allows quick calibration of the probe or its easy replacement at the end of life.

Modbus RTU on RS485

The probe output signal uses the widely used RS485 bus under the Modbus RTU protocol. Via this bus, the probes can be connected at a distance of up to 500 m directly to the control system, display or data logger. In addition to the magnitude of the measured redox potential on the 1st internal channel, the measured water temperature on channel 2 can also be read from the probe.

The four-core connection and power cable allows easy creation of a sensor network thanks to the possibility of addressing each probe. Thus, more probes of one type or several similar probes for monitoring several quantities can be connected to one RS485 bus - eg PH485 probes for pH measurement or ISE485 type probes for measuring the potential of ion-selective electrodes.

ORP485 probes can also be calibrated using the RS485 communication bus. The calibration coefficients stored in the probe allow the probes to be calibrated in the laboratory, and in the field all you have to do is connect the probe back to the measuring network.


Electrode cap KE145

Plastic electrode cap for ORP485 probes. The cap is made of a hard and smooth POM tube with an outer diameter of 33 mm and has a length of 145 mm. At one end, the cap has a 3/4" female thread.

iontově selektivní elektrody - amoniová, chloridová

TS500 and TS1700 holders

Stainless steel rod holders are designed for mechanical placement of the PH485 probe in the required location. The holder is available in lengths of 500 mm or 1700 mm - a holder of another non-standard length can be supplied on request.

iontově selektivní elektrody - amoniová, chloridová

 Rod holder TS500 equipped with a cable gland and mounted in the holder DE2

At the lower end of the holder there is a G3 / 4" internal thread for screwing on the PH485 probe and at the upper end there is a connector reduction M12 / 4F to M12 / 4M. The lower internal connector inside the M12 / 4F sensor is intended for the connection of a probe of the PH485-K2M12 type (ie a probe with a 2 m long cable terminated with an M12 / 4M connector).

Alternatively, a sensor can be supplied with a simple cable gland at the upper end for routing the cable from the PH485-xM probe (free end of the connecting cable with a length of x).


Holder DE2

An adjustable stainless steel holder DE2 can be ordered for the TS500 or TS1700 holder. It can be fastened to a railing or other vertical structure using brackets. It can also be mounted on a wall or other vertical work surface above the measured object.

The adjustable inclination of the DE2 holder allows, by extending the rod holder, to place the measuring electrode exactly at the required measuring point of the activation tank, the sump or in the open flow profile.

Držák pro snímač ISE485

 DE2 holder designed for mounting the TS500 or TS1700 rod holder


ORP electrode: platinum electrode with gel electrolyte, self-cleaning with increased mechanical resistance

Measuring electrode: platinum target with a diameter of 4 mm

Measuring range ORP (K1): -2000 mV to +2000 mV

Measurement accuracy: ± 2 mV

Measuring range temperature (K2): -5.0° C to +60.0° C

Measurement accuracy: ± 0.7° C

New probe rise time: <15 sec

ORP485-KxM connection: shielded PUR cable 4x0.25 length x m, socket end without connector

ORP485-KxM12 connection: PUR cable x m terminated with M12 / 4M connector; 4 Pins (male)

Interface: RS485, Modbus RTU protocol (FINET), default communication address 7, 19200 Bd

Supply voltage: 5 to 24 V DC / Imax <20 mA; galvanic isolation, Up> 500 V

Service life: 3 to 5 years depending on the composition of the measured medium

Storage temperature: -5° C to +60° C

Maximum working pressure: 1 bar (up to 10 bar in agreement with the manufacturer)

Dimensions: largest diameter 40 mm, length 115 mm (shortened electrodes can also be supplied)

Housing mounting threads: G3/4” on the electrode side, G3/4” on the cable outlet side

Housing material and protection: POM / IP68

Weight including cable: 150 g


Price list