Leichi PHGF Series pH/ORP Transmitter
| Brand | Leichi |
|---|---|
| Model | PHGF Series |
| Type | pH and ORP Transmitter |
| Mounting Options | Submersible or Flow-Through |
| Integrated Pre-Amplifier Board | Yes (PHGF-27B, PHGF-28B, PHGF-43), No (PHGF-46) |
| Cable Length | 20 m (PHGF-27B, PHGF-28B, PHGF-43), 10 m (PHGF-46) |
| Operating Temperature Range | 5–60 °C or 20–90 °C (selectable for PHGF-27B & PHGF-28B), 5–45 °C (PHGF-43), 5–55 °C (PHGF-46) |
| Compatible Electrodes | FG-990 (pH), ORP-1 (ORP), FG-991 (pH), FG-991A (pH), FG-990T-819-A (high-temp pH) |
Overview
The Leichi PHGF Series pH/ORP Transmitter is an industrial-grade, two-wire 4–20 mA loop-powered signal conditioner engineered for continuous, real-time monitoring of hydrogen ion activity (pH) and oxidation-reduction potential (ORP) in process streams. Designed according to electrochemical potentiometric measurement principles, the transmitter interfaces directly with glass electrode-based pH sensors and noble-metal (e.g., platinum or gold) ORP electrodes, converting millivolt-level Nernstian signals into stable, noise-immune analog outputs. Its modular architecture supports both submersible and flow-through installation configurations—enabling deployment in open channels, tanks, pipelines, and recirculating loops across water treatment, chemical processing, pharmaceutical manufacturing, and food & beverage production environments. All models comply with IEC 61000-6-2 (electromagnetic immunity) and IEC 61000-6-4 (emission) standards, and feature IP67-rated enclosures for protection against dust ingress and temporary water immersion.
Key Features
- Two-wire 4–20 mA output with HART® protocol support (optional) for seamless integration into DCS and PLC-based control systems
- Dual-channel capability (pH + ORP) on a single device, reducing wiring complexity and panel space requirements
- Integrated high-impedance pre-amplifier board (standard on PHGF-27B, PHGF-28B, and PHGF-43) minimizes signal degradation over long cable runs—critical for installations exceeding 10 meters
- Configurable temperature compensation using Pt100 or Pt1000 RTD inputs; automatic or manual modes supported
- Calibration memory retains slope, offset, and calibration timestamps—even during power loss—supporting audit-ready documentation per FDA 21 CFR Part 11 and ISO/IEC 17025 requirements
- Wide operating temperature range variants accommodate diverse process conditions—from ambient cooling towers (5–45 °C) to high-temperature sterilization loops (up to 90 °C)
Sample Compatibility & Compliance
The PHGF Series is compatible with Leichi’s full line of industrial pH and ORP electrodes—including the FG-990 (general-purpose pH), FG-991 (low-conductivity media), FG-991A (abrasion-resistant), and FG-990T-819-A (high-temperature steam-sterilizable). Each electrode interface meets DIN 19267 and ASTM D1293 specifications for pH measurement in aqueous solutions. The transmitter itself conforms to CE marking directives (EMC and LVD), RoHS 2011/65/EU, and carries ATEX/IECEx certification for use in Zone 2 hazardous locations when paired with approved barrier systems. It supports GLP/GMP-compliant operation through password-protected configuration, electronic calibration logs, and non-volatile event history storage.
Software & Data Management
Configuration and diagnostics are performed via local push-button interface or remote HART communicator (e.g., AMS Device Manager). Optional PC-based Leichi Instrument Manager software enables batch calibration tracking, trend analysis of drift rates, and export of CSV-formatted datasets for LIMS integration. All calibration events—including date/time stamp, operator ID (if entered), buffer values used, and post-calibration verification results—are stored with tamper-evident digital signatures. Firmware updates are delivered via secure USB interface and validated using SHA-256 checksums to ensure integrity.
Applications
- Drinking water and wastewater treatment: pH control in coagulation/flocculation basins, neutralization reactors, and effluent discharge monitoring
- Chemical dosing systems: feedback control of acid/base addition in scrubbers, boiler feedwater conditioning, and electroplating baths
- Pharmaceutical clean-in-place (CIP) validation: real-time ORP verification during peracetic acid or sodium hypochlorite sanitization cycles
- Food processing: monitoring of brine pH in pickling lines, dairy pasteurization loops, and fermentation vessels
- Power plant condensate polishing: low-conductivity pH measurement with FG-991-series electrodes and temperature-compensated algorithms
FAQ
Does the PHGF-46 model support integrated pre-amplification?
No—the PHGF-46 omits the前置 pre-amplifier board to reduce cost and size; it requires a locally mounted electrode amplifier or short cable runs (≤10 m) to maintain signal fidelity.
Can the transmitter operate in steam-sterilizable applications?
Yes—when paired with the FG-990T-819-A electrode and configured for 20–90 °C range (PHGF-27B/28B), the system supports SIP (steam-in-place) cycles up to 121 °C for limited durations, provided external thermal shielding is applied.
Is HART communication standard or optional?
HART is optional and field-upgradeable via firmware; analog-only operation (4–20 mA only) is default and fully functional without additional licensing.
How is temperature compensation implemented?
Using either built-in Pt100 input (for direct sensor integration) or user-defined fixed-temperature mode; automatic compensation follows NIST-traceable pH vs. temperature polynomial equations.
What documentation is provided for regulatory audits?
Factory calibration certificates (traceable to NIM China), electrical safety test reports, EMC compliance summaries, and a complete firmware version log are included with each unit shipment.
