Overview
The Rosemount 398VP-10-31-54 pH/ORP sensor is a high-performance analytical instrument designed for accurate and reliable pH and oxidation-reduction potential (ORP) measurement in harsh industrial process streams. Manufactured by Emerson (Rosemount Analytical), this sensor combines chemical-resistant materials with advanced reference junction technology to ensure minimal maintenance and extended sensor life in demanding applications.
This model features the GPHT hemi pH glass electrode for 0–14 pH measurement range, Viton O-ring material for chemical resistance, and Pt-100 RTD (resistance temperature detector) output for direct wiring to Rosemount 56, 1056, 1057, 1066, and 5081 transmitters.
Key Features
- Chemical-resistant construction: Tefzelâ„¢ and titanium wetted materials withstand chlorine dioxide, organic solvents, and oxidizing agents
- TUpH reference junction: Large-area helical reference pathway minimizes poisoning, fouling, and coating issues for extended service intervals
- Viton O-ring material: Superior chemical compatibility for aggressive process environments
- Variopol (VP 6.0) connector: Industry-standard quick-disconnect connector for easy maintenance and cable replacement
- Pt-100 RTD output: Direct compatibility with Rosemount analytical transmitters and temperature-compensated measurements
- Dual-measurement capability: Simultaneous pH (0–14) and ORP (−1500 to +1500 mV) measurement options
Technical Specifications
| Model | 398VP-10-31-54 |
| Sensor Type | pH/ORP (GPHT hemi pH glass electrode) |
| pH Measurement Range | 0 to 14 pH |
| ORP Measurement Range | -1500 to +1500 mV |
| O-ring Material | Viton® |
| Wetted Materials | Titanium, Tefzelâ„¢, glass, platinum (ORP only) |
| Temperature Sensor | Pt-100 RTD (Platinum Resistance Thermometer) |
| Connector Type | Variopol (VP 6.0) — integral to sensor |
| Transmitter Compatibility | Rosemount 56, 1056, 1057, 1066, 5081 |
| Reference Junction Type | TUpH large-area helical design |
| Manufacturer | Emerson Rosemount Analytical |
| Certifications | ATEX, IECEx (Ex ia IIC T4) |
Typical Applications
- Petrochemical: Sour water stripper monitoring and pH control
- Pulp and paper: Chlorine dioxide bleaching tower pH measurement
- Water treatment: Corrosive water streams and advanced oxidation processes
- Chemical processing: Organic solvent environments and aggressive oxidizing conditions
- Power generation: Cooling water and condensate polishing system monitoring
- Environmental monitoring: Effluent pH and ORP trending
Compatibility & Replacements
Compatible With
- Rosemount 56 Transmitter
- Rosemount 1056 Transmitter
- Rosemount 1057 Transmitter
- Rosemount 1066 Transmitter
- Rosemount 5081 Transmitter
- All Pt-100 (IEC 751 Class A/B) RTD-compatible analyzers
Replaces / Drop-In Replacement For
- 398-10-31-54 (non-VP variant with integral cable)
- Other 398 series models with equivalent electrode and O-ring specifications
Works With
- Variopol (VP 6.0) mating connector cables — required accessory
- VP8 quick-disconnect interconnecting cables
- Rosemount Analytical process tees and mounting assemblies
- Pt-100 RTD signal conditioning and transmitter modules
- SCADA, DCS, and PLC systems via Rosemount transmitter interface
