A Pyxis Labs pH and ORP probe with Modbus RTU and 4–20 mA outputs.
pH, mV, and temperature in °C — see pH and ORP.
Pyxis sells the ST-712 (P/N 53003) as a combined pH + ORP sensor in its ST-710 series; the ST-710 is pH only and the ST-711 is ORP only.
| pH range | 0–14, automatic temperature compensation, ±0.01 pH precision |
| ORP range | ±1,500 mV, ±1.0 mV precision |
| Response time | 95% within 5 seconds |
| Temperature | Reported over RS-485 Modbus only |
| Output | Modbus RTU over isolated RS-485; two isolated 4–20 mA outputs (pH and ORP) |
| 4–20 mA default scaling | pH: 4 mA = 0, 20 mA = 14. ORP: 4 mA = −1,500 mV, 20 mA = +1,500 mV |
| Wireless | Bluetooth, through a Pyxis MA-WB adapter or PowerPACK (not built into the probe) |
| Supply | 12–36 VDC, about 1 W (data sheet); the quick-start guide gives 22–26 VDC, about 2 W, so use a 24 VDC supply |
| Connector and cable | 7-pin IP67 quick connector on a 1.5 m (4.5 ft) cable, plus a flying-lead adapter cable (MA-1100) |
| Wetted materials | CPVC housing (the quick-start guide says UPVC), flat pH bulb, platinum ORP disk, stainless-steel solution-ground tip |
| Process connection | ST-001 tee (supplied), 3/4 in FNPT; or the MA-102S submersion adapter |
| Pressure and temperature limits | Up to 0.7 MPa (100 psi); 4–49 °C (40–120 °F) operating, −20–60 °C (−4–140 °F) storage |
| Ingress rating | IP67 |
Wire colors:
| Wire | Function |
|---|---|
| Red | 24 V + |
| Black | 24 V power ground and 4–20 mA − |
| White | 4–20 mA + for pH |
| Green | 4–20 mA + for ORP |
| Blue | RS-485 A |
| Yellow | RS-485 B |
| Clear | Shield, solution ground |
Pyxis does not publish the ST-712’s Modbus register map or serial settings; contact service@pyxis-lab.com for them. The registers the InteliHive uses are listed on the Modbus Register Map.
The ST-712 has no replaceable electrode and no KCl to refill. It runs until the end of its life, typically two years or more, and is then replaced.
Wiring and configuration live with each controller: