A Pulsafeeder ORP probe for use with Pulsafeeder controllers.
Some ratings are not filled in yet. Check the manufacturer’s current datasheet before wiring.
¶ What it measures
Oxidation-reduction potential, in mV — see ORP.
¶ Electrical interface
| Model | From datasheet — to be filled in |
| Output | Electrode signal to a MicroVision EX probe input; ORP sensors are prewired to Probe 3 |
| Controller reading range | −2,000 to +2,000 mV |
| Process connection | From datasheet — to be filled in |
| Pressure and temperature limits | 125 psi (8.6 bar), 50 °C (122 °F) maximum |
| Materials | Polypropylene |
| Flow | 1–5 GPM past the probe |
| Maximum cable length | 30.5 m (100 ft) |
The pressure, temperature, material, flow and cable figures are Pulsafeeder’s specification for the standard ORP probe supplied with the MicroVision EX. Pulsafeeder supplies it already installed in a tee.
¶ Maintenance
Pulsafeeder’s MicroVision EX manual gives this care for the ORP probe supplied with the controller. ORP probes are coated and abraded by the water and can be poisoned by chemicals if the system runs out of control, so test them against standards.
- Test — immerse the probe in 100 mV ORP standard; it should read within ±10 mV. Rinse it well with water and immerse it in 465 mV standard; it should respond quickly. The difference between the two should be about 365 mV.
- If it passes — flush the probe with deionized water and put it back in service.
- If it is off by more than 10 mV — clean it with aqua regia (three volumes hydrochloric acid to one volume concentrated nitric acid) and repeat the test.
- Calibration — most applications do not need an ORP calibration. If needed, calibrate one point from the MicroVision EX Probe Cal screen, with flow across the probe for at least 5 minutes first.
- Storage — keep the tip wet when it is out of the line (standard practice for ORP electrodes).
- Removal — always depressurise the piping before removing the probe.
Aqua regia is highly corrosive. Wear rubber gloves, eye protection and protective clothing, and handle it only if you are trained to.
¶ Using it with a controller
Wiring and configuration live with each controller:
- MicroVision EX — see MicroVision EX. A setup guide is not written yet.